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dotnet windows forms databinding : INotifyPropertyChanged Bug ?
I'm not sure if i'm misunderstanding how INotifyPropertyChanged should work but it's not working as I expected. I have a sample program with a very simple 'Customer' class with three properties code, name & address. All these are bound to a form via a BindingSource and fire the PropertyChanged event when the property is modified. I change one of these properties in code and find that all of the properties are fetched and rebound to the form. Is this correct ? What's the point of specifying a property name in the PropertyChangedEventArgs if all the controls are rebound anyway. Any help would be much appreciated John If it's any help my code is below using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Text; using System.Windows.Forms; namespace NotifyChange { public partial class Form1 : Form { private Customer _customer; public Form1() { InitializeComponent(); _customer = new Customer(); _customer.Code = "G001"; _customer.Name = "Greenwood Enterpises Ltd"; _customer.Address = "128 Smithey Road"; customerBindingSource.DataSource = _customer; } private void button1_Click(object sender, EventArgs e) { Console.WriteLine("<-- Change Code --"); _customer.Code = "F001"; Console.WriteLine("-- Change Code -->"); } private void button2_Click(object sender, EventArgs e) { Console.WriteLine("<-- Change Name --"); _customer.Name = "Fletcher Business Services Ltd"; Console.WriteLine("-- Change Name -->"); } } public class Customer : INotifyPropertyChanged { private string _code = ""; private string _name = ""; private string _address = ""; public string Code { get { Console.WriteLine("Got 'Code' at {0}", DateTime.Now); return _code; } set { if (_code != value) { _code = value; NotifyPropertyChanged(" Code"); } } } public string Name { get { Console.WriteLine("Got 'Name' at {0}", DateTime.Now); return _name; } set { if (_name != value) { _name = value; NotifyPropertyChanged("Name"); } } } public string Address { get { Console.WriteLine("Got 'Address' at {0}", DateTime.Now); return _address; } set { _address = value; } } private void NotifyPropertyChanged(string Name) { if (PropertyChanged != null) { PropertyChanged(this, new PropertyChangedEventArgs(Name)); } } #region INotifyPropertyChanged Members public event PropertyChangedEventHandler PropertyChanged; #endregion
Hi,
[quoted text, click to view] "John Greenwood" <john.greenwood@bhpit.co.uk> wrote in message news:1j1er252pmquk9pi3786qocb32ahkqf38f@4ax.com... > Hi, > > I'm not sure if i'm misunderstanding how INotifyPropertyChanged should > work but it's not working as I expected. > > I have a sample program with a very simple 'Customer' class with three > properties code, name & address. All these are bound to a form via a > BindingSource and fire the PropertyChanged event when the property is > modified. > > I change one of these properties in code and find that all of the > properties are fetched and rebound to the form. Is this correct ? Yes it is. Any property changed event will result in BindingManagerBase.PushData which causes a PushData on *all* its Bindings. [quoted text, click to view] > What's the point of specifying a property name in the When it comes to WinForms databinding there is no point afaik. But remember that INotifyPropertyChanged can be used elsewhere too, eg. for the PropertyGrid (dunno if it refreshes all properties on change there) and also for WPF (where it doesn't refresh all properties on change). HTH, Greetings [quoted text, click to view] > PropertyChangedEventArgs if all the controls are rebound anyway. > > Any help would be much appreciated > > John > > If it's any help my code is below > > using System; > using System.Collections.Generic; > using System.ComponentModel; > using System.Data; > using System.Drawing; > using System.Text; > using System.Windows.Forms; > > namespace NotifyChange > { > public partial class Form1 : Form > { > private Customer _customer; > > public Form1() > { > InitializeComponent(); > _customer = new Customer(); > _customer.Code = "G001"; > _customer.Name = "Greenwood Enterpises Ltd"; > _customer.Address = "128 Smithey Road"; > customerBindingSource.DataSource = _customer; > } > > private void button1_Click(object sender, EventArgs e) > { > Console.WriteLine("<-- Change Code --"); > > _customer.Code = "F001"; > > Console.WriteLine("-- Change Code -->"); > } > > private void button2_Click(object sender, EventArgs e) > { > Console.WriteLine("<-- Change Name --"); > > _customer.Name = "Fletcher Business Services Ltd"; > > Console.WriteLine("-- Change Name -->"); > } > > } > > public class Customer : INotifyPropertyChanged > { > > private string _code = ""; > private string _name = ""; > private string _address = ""; > > public string Code > { > get > { > Console.WriteLine("Got 'Code' at {0}", DateTime.Now); > return _code; > } > set > { > if (_code != value) > { > _code = value; > > NotifyPropertyChanged(" Code"); > } > } > } > > public string Name > { > get > { > Console.WriteLine("Got 'Name' at {0}", DateTime.Now); > return _name; > } > set > { > if (_name != value) > { > _name = value; > > NotifyPropertyChanged("Name"); > } > } > } > > public string Address > { > get > { > Console.WriteLine("Got 'Address' at {0}", > DateTime.Now); > return _address; > } > set > { > _address = value; > } > } > > private void NotifyPropertyChanged(string Name) > { > > if (PropertyChanged != null) > { > PropertyChanged(this, new > PropertyChangedEventArgs(Name)); > } > } > #region INotifyPropertyChanged Members > > public event PropertyChangedEventHandler PropertyChanged; > > #endregion > }
Hi Bart,
Some of the properties on my class were totals built dynamically every time they were accessed and so of course were being rebuilt every time another property from the same class issued the change event. At least now I know and I can avoid similar situations in the future. Cheers John On Wed, 24 Jan 2007 15:28:43 GMT, "Bart Mermuys" [quoted text, click to view] <bmermuys.nospam@hotmail.com> wrote:
>Hi, > >"John Greenwood" <john.greenwood@bhpit.co.uk> wrote in message >news:1j1er252pmquk9pi3786qocb32ahkqf38f@4ax.com... >> Hi, >> >> I'm not sure if i'm misunderstanding how INotifyPropertyChanged should >> work but it's not working as I expected. >> >> I have a sample program with a very simple 'Customer' class with three >> properties code, name & address. All these are bound to a form via a >> BindingSource and fire the PropertyChanged event when the property is >> modified. >> >> I change one of these properties in code and find that all of the >> properties are fetched and rebound to the form. Is this correct ? > >Yes it is. Any property changed event will result in >BindingManagerBase.PushData which causes a PushData on *all* its Bindings. > >> What's the point of specifying a property name in the > >When it comes to WinForms databinding there is no point afaik. But >remember that INotifyPropertyChanged can be used elsewhere too, eg. for the >PropertyGrid (dunno if it refreshes all properties on change there) and also >for WPF (where it doesn't refresh all properties on change). > >HTH, >Greetings > > >> PropertyChangedEventArgs if all the controls are rebound anyway. >> >> Any help would be much appreciated >> >> John >> >> If it's any help my code is below >> >> using System; >> using System.Collections.Generic; >> using System.ComponentModel; >> using System.Data; >> using System.Drawing; >> using System.Text; >> using System.Windows.Forms; >> >> namespace NotifyChange >> { >> public partial class Form1 : Form >> { >> private Customer _customer; >> >> public Form1() >> { >> InitializeComponent(); >> _customer = new Customer(); >> _customer.Code = "G001"; >> _customer.Name = "Greenwood Enterpises Ltd"; >> _customer.Address = "128 Smithey Road"; >> customerBindingSource.DataSource = _customer; >> } >> >> private void button1_Click(object sender, EventArgs e) >> { >> Console.WriteLine("<-- Change Code --"); >> >> _customer.Code = "F001"; >> >> Console.WriteLine("-- Change Code -->"); >> } >> >> private void button2_Click(object sender, EventArgs e) >> { >> Console.WriteLine("<-- Change Name --"); >> >> _customer.Name = "Fletcher Business Services Ltd"; >> >> Console.WriteLine("-- Change Name -->"); >> } >> >> } >> >> public class Customer : INotifyPropertyChanged >> { >> >> private string _code = ""; >> private string _name = ""; >> private string _address = ""; >> >> public string Code >> { >> get >> { >> Console.WriteLine("Got 'Code' at {0}", DateTime.Now); >> return _code; >> } >> set >> { >> if (_code != value) >> { >> _code = value; >> >> NotifyPropertyChanged(" Code"); >> } >> } >> } >> >> public string Name >> { >> get >> { >> Console.WriteLine("Got 'Name' at {0}", DateTime.Now); >> return _name; >> } >> set >> { >> if (_name != value) >> { >> _name = value; >> >> NotifyPropertyChanged("Name"); >> } >> } >> } >> >> public string Address >> { >> get >> { >> Console.WriteLine("Got 'Address' at {0}", >> DateTime.Now); >> return _address; >> } >> set >> { >> _address = value; >> } >> } >> >> private void NotifyPropertyChanged(string Name) >> { >> >> if (PropertyChanged != null) >> { >> PropertyChanged(this, new >> PropertyChangedEventArgs(Name)); >> } >> } >> #region INotifyPropertyChanged Members >> >> public event PropertyChangedEventHandler PropertyChanged; >> >> #endregion >> } >
[quoted text, click to view]
John Greenwood wrote: I am also having problems with this. The objects in my BindingList > Hi Bart, > > Some of the properties on my class were totals built dynamically every > time they were accessed and so of course were being rebuilt every > time another property from the same class issued the change event. > > At least now I know and I can avoid similar situations in the future. > > Cheers > > John > > > On Wed, 24 Jan 2007 15:28:43 GMT, "Bart Mermuys" > <bmermuys.nospam@hotmail.com> wrote: > >> Hi, >> >> "John Greenwood" <john.greenwood@bhpit.co.uk> wrote in message >> news:1j1er252pmquk9pi3786qocb32ahkqf38f@4ax.com... >>> Hi, >>> >>> I'm not sure if i'm misunderstanding how INotifyPropertyChanged should >>> work but it's not working as I expected. >>> >>> I have a sample program with a very simple 'Customer' class with three >>> properties code, name & address. All these are bound to a form via a >>> BindingSource and fire the PropertyChanged event when the property is >>> modified. >>> >>> I change one of these properties in code and find that all of the >>> properties are fetched and rebound to the form. Is this correct ? >> Yes it is. Any property changed event will result in >> BindingManagerBase.PushData which causes a PushData on *all* its Bindings. >> >>> What's the point of specifying a property name in the >> When it comes to WinForms databinding there is no point afaik. But >> remember that INotifyPropertyChanged can be used elsewhere too, eg. for the >> PropertyGrid (dunno if it refreshes all properties on change there) and also >> for WPF (where it doesn't refresh all properties on change). >> >> HTH, >> Greetings >> >> >>> PropertyChangedEventArgs if all the controls are rebound anyway. >>> >>> Any help would be much appreciated >>> >>> John >>> >>> If it's any help my code is below >>> >>> using System; >>> using System.Collections.Generic; >>> using System.ComponentModel; >>> using System.Data; >>> using System.Drawing; >>> using System.Text; >>> using System.Windows.Forms; >>> >>> namespace NotifyChange >>> { >>> public partial class Form1 : Form >>> { >>> private Customer _customer; >>> >>> public Form1() >>> { >>> InitializeComponent(); >>> _customer = new Customer(); >>> _customer.Code = "G001"; >>> _customer.Name = "Greenwood Enterpises Ltd"; >>> _customer.Address = "128 Smithey Road"; >>> customerBindingSource.DataSource = _customer; >>> } >>> >>> private void button1_Click(object sender, EventArgs e) >>> { >>> Console.WriteLine("<-- Change Code --"); >>> >>> _customer.Code = "F001"; >>> >>> Console.WriteLine("-- Change Code -->"); >>> } >>> >>> private void button2_Click(object sender, EventArgs e) >>> { >>> Console.WriteLine("<-- Change Name --"); >>> >>> _customer.Name = "Fletcher Business Services Ltd"; >>> >>> Console.WriteLine("-- Change Name -->"); >>> } >>> >>> } >>> >>> public class Customer : INotifyPropertyChanged >>> { >>> >>> private string _code = ""; >>> private string _name = ""; >>> private string _address = ""; >>> >>> public string Code >>> { >>> get >>> { >>> Console.WriteLine("Got 'Code' at {0}", DateTime.Now); >>> return _code; >>> } >>> set >>> { >>> if (_code != value) >>> { >>> _code = value; >>> >>> NotifyPropertyChanged(" Code"); >>> } >>> } >>> } >>> >>> public string Name >>> { >>> get >>> { >>> Console.WriteLine("Got 'Name' at {0}", DateTime.Now); >>> return _name; >>> } >>> set >>> { >>> if (_name != value) >>> { >>> _name = value; >>> >>> NotifyPropertyChanged("Name"); >>> } >>> } >>> } >>> >>> public string Address >>> { >>> get >>> { >>> Console.WriteLine("Got 'Address' at {0}", >>> DateTime.Now); >>> return _address; >>> } >>> set >>> { >>> _address = value; >>> } >>> } >>> >>> private void NotifyPropertyChanged(string Name) >>> { >>> >>> if (PropertyChanged != null) >>> { >>> PropertyChanged(this, new >>> PropertyChangedEventArgs(Name)); >>> } >>> } >>> #region INotifyPropertyChanged Members >>> >>> public event PropertyChangedEventHandler PropertyChanged; >>> >>> #endregion >>> } > implement INotifyPropertyChange. If I use the Windows Forms designer to layout the BindingSource as a DataGridView things look pretty good. If my objects change I see the changes in the grid. But If I start editing a cell I must complete the edit very quickly or I risk having the BindingManagerBase.PushData() reset my edit to the previous value. Is there anyway to prevent the BindingSource from reseting a DataGridView cell while I am in the middle of editing when a different property triggers a BindingManagerBase.PushData()? Thanks,
I'm assuming when you say you implemented INotifyPropertyChanged, you
implemented it on the Customer Class. Did you also implement IEditableObject, and put in the code to save the original values, then populate them if the insert/udpate was cancelled? I have a DGV bound to a list of business objects and I'm not having any of these problems with it. Robin S. Ts'i mahnu uterna ot twan ot geifur hingts uto. ----------------------------------------------- [quoted text, click to view] "Doug Crawford" <webmail@nospam.com> wrote in message news:eiHC9buWHHA.4384@TK2MSFTNGP02.phx.gbl... > John Greenwood wrote: >> Hi Bart, >> >> Some of the properties on my class were totals built dynamically every >> time they were accessed and so of course were being rebuilt every >> time another property from the same class issued the change event. >> >> At least now I know and I can avoid similar situations in the future. >> >> Cheers >> >> John >> >> >> On Wed, 24 Jan 2007 15:28:43 GMT, "Bart Mermuys" >> <bmermuys.nospam@hotmail.com> wrote: >> >>> Hi, >>> >>> "John Greenwood" <john.greenwood@bhpit.co.uk> wrote in message >>> news:1j1er252pmquk9pi3786qocb32ahkqf38f@4ax.com... >>>> Hi, >>>> >>>> I'm not sure if i'm misunderstanding how INotifyPropertyChanged should >>>> work but it's not working as I expected. >>>> >>>> I have a sample program with a very simple 'Customer' class with three >>>> properties code, name & address. All these are bound to a form via a >>>> BindingSource and fire the PropertyChanged event when the property is >>>> modified. >>>> >>>> I change one of these properties in code and find that all of the >>>> properties are fetched and rebound to the form. Is this correct ? >>> Yes it is. Any property changed event will result in >>> BindingManagerBase.PushData which causes a PushData on *all* its >>> Bindings. >>> >>>> What's the point of specifying a property name in the >>> When it comes to WinForms databinding there is no point afaik. But >>> remember that INotifyPropertyChanged can be used elsewhere too, eg. for >>> the PropertyGrid (dunno if it refreshes all properties on change there) >>> and also for WPF (where it doesn't refresh all properties on change). >>> >>> HTH, >>> Greetings >>> >>> >>>> PropertyChangedEventArgs if all the controls are rebound anyway. >>>> >>>> Any help would be much appreciated >>>> >>>> John >>>> >>>> If it's any help my code is below >>>> >>>> using System; >>>> using System.Collections.Generic; >>>> using System.ComponentModel; >>>> using System.Data; >>>> using System.Drawing; >>>> using System.Text; >>>> using System.Windows.Forms; >>>> >>>> namespace NotifyChange >>>> { >>>> public partial class Form1 : Form >>>> { >>>> private Customer _customer; >>>> >>>> public Form1() >>>> { >>>> InitializeComponent(); >>>> _customer = new Customer(); >>>> _customer.Code = "G001"; >>>> _customer.Name = "Greenwood Enterpises Ltd"; >>>> _customer.Address = "128 Smithey Road"; >>>> customerBindingSource.DataSource = _customer; >>>> } >>>> >>>> private void button1_Click(object sender, EventArgs e) >>>> { >>>> Console.WriteLine("<-- Change Code --"); >>>> >>>> _customer.Code = "F001"; >>>> >>>> Console.WriteLine("-- Change Code -->"); >>>> } >>>> >>>> private void button2_Click(object sender, EventArgs e) >>>> { >>>> Console.WriteLine("<-- Change Name --"); >>>> >>>> _customer.Name = "Fletcher Business Services Ltd"; >>>> >>>> Console.WriteLine("-- Change Name -->"); >>>> } >>>> >>>> } >>>> >>>> public class Customer : INotifyPropertyChanged >>>> { >>>> >>>> private string _code = ""; >>>> private string _name = ""; >>>> private string _address = ""; >>>> >>>> public string Code >>>> { >>>> get >>>> { >>>> Console.WriteLine("Got 'Code' at {0}", DateTime.Now); >>>> return _code; >>>> } >>>> set >>>> { >>>> if (_code != value) >>>> { >>>> _code = value; >>>> >>>> NotifyPropertyChanged(" Code"); >>>> } >>>> } >>>> } >>>> >>>> public string Name >>>> { >>>> get >>>> { >>>> Console.WriteLine("Got 'Name' at {0}", DateTime.Now); >>>> return _name; >>>> } >>>> set >>>> { >>>> if (_name != value) >>>> { >>>> _name = value; >>>> >>>> NotifyPropertyChanged("Name"); >>>> } >>>> } >>>> } >>>> >>>> public string Address >>>> { >>>> get >>>> { >>>> Console.WriteLine("Got 'Address' at {0}", >>>> DateTime.Now); >>>> return _address; >>>> } >>>> set >>>> { >>>> _address = value; >>>> } >>>> } >>>> >>>> private void NotifyPropertyChanged(string Name) >>>> { >>>> >>>> if (PropertyChanged != null) >>>> { >>>> PropertyChanged(this, new >>>> PropertyChangedEventArgs(Name)); >>>> } >>>> } >>>> #region INotifyPropertyChanged Members >>>> >>>> public event PropertyChangedEventHandler PropertyChanged; >>>> >>>> #endregion >>>> } >> > I am also having problems with this. The objects in my BindingList > implement INotifyPropertyChange. If I use the Windows Forms designer to > layout the BindingSource as a DataGridView things look pretty good. If > my objects change I see the changes in the grid. But If I start editing > a cell I must complete the edit very quickly or I risk having the > BindingManagerBase.PushData() reset my edit to the previous value. Is > there anyway to prevent the BindingSource from reseting a DataGridView > cell while I am in the middle of editing when a different property > triggers a BindingManagerBase.PushData()? > > Thanks, > Doug
Yes, if we follow the example in this thread I implemented
INotifyPropertyChanged on the Customer class. I did not implement IEditableObject, but I am not sure that is going to help. My main problem is that any change to an individual property in the Customer class causes the binding mechanism to globally push all of the Customer Properties to the Form controls (The property string name in the PropertyChangedEventArgs appears to be ignored). So lets say you are editing Customer.Name in the DataGridView and while you are editing something else changes Cusomter.Code in the data source. I was hoping to just see the cell under the Code column change, but actually all of the columns in the selected record are updated including the cell I am currently editing. Maybe I should be implementing IEditableObject and prevent the Customer class from triggering the PropertyChanged event until the edit is complete. Will my Customer.BeginEdit() method be called when a user starts editing a TextBox that is databound to a Customer property, or does this mechanism only work with the DataGridView? Doug [quoted text, click to view] RobinS wrote:
> I'm assuming when you say you implemented INotifyPropertyChanged, you > implemented it on the Customer Class. Did you also implement > IEditableObject, and put in the code to save the original values, then > populate them if the insert/udpate was cancelled? > > I have a DGV bound to a list of business objects and I'm not having any of > these problems with it. > > Robin S. > Ts'i mahnu uterna ot twan ot geifur hingts uto. > ----------------------------------------------- > "Doug Crawford" <webmail@nospam.com> wrote in message > news:eiHC9buWHHA.4384@TK2MSFTNGP02.phx.gbl... >> John Greenwood wrote: >>> Hi Bart, >>> >>> Some of the properties on my class were totals built dynamically every >>> time they were accessed and so of course were being rebuilt every >>> time another property from the same class issued the change event. >>> >>> At least now I know and I can avoid similar situations in the future. >>> >>> Cheers >>> >>> John >>> >>> >>> On Wed, 24 Jan 2007 15:28:43 GMT, "Bart Mermuys" >>> <bmermuys.nospam@hotmail.com> wrote: >>> >>>> Hi, >>>> >>>> "John Greenwood" <john.greenwood@bhpit.co.uk> wrote in message >>>> news:1j1er252pmquk9pi3786qocb32ahkqf38f@4ax.com... >>>>> Hi, >>>>> >>>>> I'm not sure if i'm misunderstanding how INotifyPropertyChanged should >>>>> work but it's not working as I expected. >>>>> >>>>> I have a sample program with a very simple 'Customer' class with three >>>>> properties code, name & address. All these are bound to a form via a >>>>> BindingSource and fire the PropertyChanged event when the property is >>>>> modified. >>>>> >>>>> I change one of these properties in code and find that all of the >>>>> properties are fetched and rebound to the form. Is this correct ? >>>> Yes it is. Any property changed event will result in >>>> BindingManagerBase.PushData which causes a PushData on *all* its >>>> Bindings. >>>> >>>>> What's the point of specifying a property name in the >>>> When it comes to WinForms databinding there is no point afaik. But >>>> remember that INotifyPropertyChanged can be used elsewhere too, eg. for >>>> the PropertyGrid (dunno if it refreshes all properties on change there) >>>> and also for WPF (where it doesn't refresh all properties on change). >>>> >>>> HTH, >>>> Greetings >>>> >>>> >>>>> PropertyChangedEventArgs if all the controls are rebound anyway. >>>>> >>>>> Any help would be much appreciated >>>>> >>>>> John >>>>> >>>>> If it's any help my code is below >>>>> >>>>> using System; >>>>> using System.Collections.Generic; >>>>> using System.ComponentModel; >>>>> using System.Data; >>>>> using System.Drawing; >>>>> using System.Text; >>>>> using System.Windows.Forms; >>>>> >>>>> namespace NotifyChange >>>>> { >>>>> public partial class Form1 : Form >>>>> { >>>>> private Customer _customer; >>>>> >>>>> public Form1() >>>>> { >>>>> InitializeComponent(); >>>>> _customer = new Customer(); >>>>> _customer.Code = "G001"; >>>>> _customer.Name = "Greenwood Enterpises Ltd"; >>>>> _customer.Address = "128 Smithey Road"; >>>>> customerBindingSource.DataSource = _customer; >>>>> } >>>>> >>>>> private void button1_Click(object sender, EventArgs e) >>>>> { >>>>> Console.WriteLine("<-- Change Code --"); >>>>> >>>>> _customer.Code = "F001"; >>>>> >>>>> Console.WriteLine("-- Change Code -->"); >>>>> } >>>>> >>>>> private void button2_Click(object sender, EventArgs e) >>>>> { >>>>> Console.WriteLine("<-- Change Name --"); >>>>> >>>>> _customer.Name = "Fletcher Business Services Ltd"; >>>>> >>>>> Console.WriteLine("-- Change Name -->"); >>>>> } >>>>> >>>>> } >>>>> >>>>> public class Customer : INotifyPropertyChanged >>>>> { >>>>> >>>>> private string _code = ""; >>>>> private string _name = ""; >>>>> private string _address = ""; >>>>> >>>>> public string Code >>>>> { >>>>> get >>>>> { >>>>> Console.WriteLine("Got 'Code' at {0}", DateTime.Now); >>>>> return _code; >>>>> } >>>>> set >>>>> { >>>>> if (_code != value) >>>>> { >>>>> _code = value; >>>>> >>>>> NotifyPropertyChanged(" Code"); >>>>> } >>>>> } >>>>> } >>>>> >>>>> public string Name >>>>> { >>>>> get >>>>> { >>>>> Console.WriteLine("Got 'Name' at {0}", DateTime.Now); >>>>> return _name; >>>>> } >>>>> set >>>>> { >>>>> if (_name != value) >>>>> { >>>>> _name = value; >>>>> >>>>> NotifyPropertyChanged("Name"); >>>>> } >>>>> } >>>>> } >>>>> >>>>> public string Address >>>>> { >>>>> get >>>>> { >>>>> Console.WriteLine("Got 'Address' at {0}", >>>>> DateTime.Now); >>>>> return _address; >>>>> } >>>>> set >>>>> { >>>>> _address = value; >>>>> } >>>>> } >>>>> >>>>> private void NotifyPropertyChanged(string Name) >>>>> { >>>>> >>>>> if (PropertyChanged != null) >>>>> { >>>>> PropertyChanged(this, new >>>>> PropertyChangedEventArgs(Name)); >>>>> } >>>>> } >>>>> #region INotifyPropertyChanged Members >>>>>
I think the BeginEdit/EndEdit/CancelEdit methods could help you. I think
BeginEdit applies to any control, not just to a DGV. What else is changing your data source? Is it the same user, or some other user? How are they changing your business object? You could also un-implement INotifyPropertyChanged; I don't know what other ramifications this would have, though. Robin S. --------------------------------------------- [quoted text, click to view] "Doug Crawford" <webmail@nospam.com> wrote in message
news:us92M44WHHA.1180@TK2MSFTNGP05.phx.gbl... > Yes, if we follow the example in this thread I implemented > INotifyPropertyChanged on the Customer class. I did not implement > IEditableObject, but I am not sure that is going to help. My main > problem is that any change to an individual property in the Customer > class causes the binding mechanism to globally push all of the Customer > Properties to the Form controls (The property string name in the > PropertyChangedEventArgs appears to be ignored). > > So lets say you are editing Customer.Name in the DataGridView and while > you are editing something else changes Cusomter.Code in the data source. > I was hoping to just see the cell under the Code column change, but > actually all of the columns in the selected record are updated including > the cell I am currently editing. > > Maybe I should be implementing IEditableObject and prevent the Customer > class from triggering the PropertyChanged event until the edit is > complete. > > Will my Customer.BeginEdit() method be called when a user starts editing > a TextBox that is databound to a Customer property, or does this > mechanism only work with the DataGridView? > > Doug > > > > RobinS wrote: >> I'm assuming when you say you implemented INotifyPropertyChanged, you >> implemented it on the Customer Class. Did you also implement >> IEditableObject, and put in the code to save the original values, then >> populate them if the insert/udpate was cancelled? >> >> I have a DGV bound to a list of business objects and I'm not having any >> of these problems with it. >> >> Robin S. >> Ts'i mahnu uterna ot twan ot geifur hingts uto. >> ----------------------------------------------- >> "Doug Crawford" <webmail@nospam.com> wrote in message >> news:eiHC9buWHHA.4384@TK2MSFTNGP02.phx.gbl... >>> John Greenwood wrote: >>>> Hi Bart, >>>> >>>> Some of the properties on my class were totals built dynamically every >>>> time they were accessed and so of course were being rebuilt every >>>> time another property from the same class issued the change event. >>>> >>>> At least now I know and I can avoid similar situations in the future. >>>> >>>> Cheers >>>> >>>> John >>>> >>>> >>>> On Wed, 24 Jan 2007 15:28:43 GMT, "Bart Mermuys" >>>> <bmermuys.nospam@hotmail.com> wrote: >>>> >>>>> Hi, >>>>> >>>>> "John Greenwood" <john.greenwood@bhpit.co.uk> wrote in message >>>>> news:1j1er252pmquk9pi3786qocb32ahkqf38f@4ax.com... >>>>>> Hi, >>>>>> >>>>>> I'm not sure if i'm misunderstanding how INotifyPropertyChanged >>>>>> should >>>>>> work but it's not working as I expected. >>>>>> >>>>>> I have a sample program with a very simple 'Customer' class with >>>>>> three >>>>>> properties code, name & address. All these are bound to a form via a >>>>>> BindingSource and fire the PropertyChanged event when the property >>>>>> is >>>>>> modified. >>>>>> >>>>>> I change one of these properties in code and find that all of the >>>>>> properties are fetched and rebound to the form. Is this correct ? >>>>> Yes it is. Any property changed event will result in >>>>> BindingManagerBase.PushData which causes a PushData on *all* its >>>>> Bindings. >>>>> >>>>>> What's the point of specifying a property name in the >>>>> When it comes to WinForms databinding there is no point afaik. But >>>>> remember that INotifyPropertyChanged can be used elsewhere too, eg. >>>>> for the PropertyGrid (dunno if it refreshes all properties on change >>>>> there) and also for WPF (where it doesn't refresh all properties on >>>>> change). >>>>> >>>>> HTH, >>>>> Greetings >>>>> >>>>> >>>>>> PropertyChangedEventArgs if all the controls are rebound anyway. >>>>>> >>>>>> Any help would be much appreciated >>>>>> >>>>>> John >>>>>> >>>>>> If it's any help my code is below >>>>>> >>>>>> using System; >>>>>> using System.Collections.Generic; >>>>>> using System.ComponentModel; >>>>>> using System.Data; >>>>>> using System.Drawing; >>>>>> using System.Text; >>>>>> using System.Windows.Forms; >>>>>> >>>>>> namespace NotifyChange >>>>>> { >>>>>> public partial class Form1 : Form >>>>>> { >>>>>> private Customer _customer; >>>>>> >>>>>> public Form1() >>>>>> { >>>>>> InitializeComponent(); >>>>>> _customer = new Customer(); >>>>>> _customer.Code = "G001"; >>>>>> _customer.Name = "Greenwood Enterpises Ltd"; >>>>>> _customer.Address = "128 Smithey Road"; >>>>>> customerBindingSource.DataSource = _customer; >>>>>> } >>>>>> >>>>>> private void button1_Click(object sender, EventArgs e) >>>>>> { >>>>>> Console.WriteLine("<-- Change Code --"); >>>>>> >>>>>> _customer.Code = "F001"; >>>>>> >>>>>> Console.WriteLine("-- Change Code -->"); >>>>>> } >>>>>> >>>>>> private void button2_Click(object sender, EventArgs e) >>>>>> { >>>>>> Console.WriteLine("<-- Change Name --"); >>>>>> >>>>>> _customer.Name = "Fletcher Business Services Ltd"; >>>>>> >>>>>> Console.WriteLine("-- Change Name -->"); >>>>>> } >>>>>> >>>>>> } >>>>>> >>>>>> public class Customer : INotifyPropertyChanged >>>>>> { >>>>>> >>>>>> private string _code = ""; >>>>>> private string _name = ""; >>>>>> private string _address = ""; >>>>>> >>>>>> public string Code >>>>>> { >>>>>> get >>>>>> { >>>>>> Console.WriteLine("Got 'Code' at {0}", DateTime.Now); >>>>>> return _code; >>>>>> } >>>>>> set >>>>>> { >>>>>> if (_code != value) >>>>>> { >>>>>> _code = value; >>>>>> >>>>>> NotifyPropertyChanged(" Code"); >>>>>> } >>>>>> } >>>>>> } >>>>>> >>>>>> public string Name >>>>>> { >>>>>> get >>>>>> { >>>>>> Console.WriteLine("Got 'Name' at {0}", DateTime.Now); >>>>>> return _name; >>>>>> } >>>>>> set >>>>>> { >>>>>> if (_name != value) >>>>>> { >>>>>> _name = value; >>>>>> >>>>>> NotifyPropertyChanged("Name");
My "business object" is not really the traditional use case of a
Customer row in a database. It is more analogous to real time status data with just one editable property. I did discover that if I toggle the value of the RaiseListChangedEvents property on the BindingSource I can temporarily suppress change notifications, so I think this approach will work. Doug [quoted text, click to view] RobinS wrote:
> I think the BeginEdit/EndEdit/CancelEdit methods could help you. I think > BeginEdit applies to any control, not just to a DGV. > > What else is changing your data source? Is it the same user, or some other > user? How are they changing your business object? > > You could also un-implement INotifyPropertyChanged; I don't know what other > ramifications this would have, though. > > Robin S. > --------------------------------------------- > "Doug Crawford" <webmail@nospam.com> wrote in message > news:us92M44WHHA.1180@TK2MSFTNGP05.phx.gbl... >> Yes, if we follow the example in this thread I implemented >> INotifyPropertyChanged on the Customer class. I did not implement >> IEditableObject, but I am not sure that is going to help. My main >> problem is that any change to an individual property in the Customer >> class causes the binding mechanism to globally push all of the Customer >> Properties to the Form controls (The property string name in the >> PropertyChangedEventArgs appears to be ignored). >> >> So lets say you are editing Customer.Name in the DataGridView and while >> you are editing something else changes Cusomter.Code in the data source. >> I was hoping to just see the cell under the Code column change, but >> actually all of the columns in the selected record are updated including >> the cell I am currently editing. >> >> Maybe I should be implementing IEditableObject and prevent the Customer >> class from triggering the PropertyChanged event until the edit is >> complete. >> >> Will my Customer.BeginEdit() method be called when a user starts editing >> a TextBox that is databound to a Customer property, or does this >> mechanism only work with the DataGridView? >> >> Doug >> >> >> >> RobinS wrote: >>> I'm assuming when you say you implemented INotifyPropertyChanged, you >>> implemented it on the Customer Class. Did you also implement >>> IEditableObject, and put in the code to save the original values, then >>> populate them if the insert/udpate was cancelled? >>> >>> I have a DGV bound to a list of business objects and I'm not having any >>> of these problems with it. >>> >>> Robin S. >>> Ts'i mahnu uterna ot twan ot geifur hingts uto. >>> ----------------------------------------------- >>> "Doug Crawford" <webmail@nospam.com> wrote in message >>> news:eiHC9buWHHA.4384@TK2MSFTNGP02.phx.gbl... >>>> John Greenwood wrote: >>>>> Hi Bart, >>>>> >>>>> Some of the properties on my class were totals built dynamically every >>>>> time they were accessed and so of course were being rebuilt every >>>>> time another property from the same class issued the change event. >>>>> >>>>> At least now I know and I can avoid similar situations in the future. >>>>> >>>>> Cheers >>>>> >>>>> John >>>>> >>>>> >>>>> On Wed, 24 Jan 2007 15:28:43 GMT, "Bart Mermuys" >>>>> <bmermuys.nospam@hotmail.com> wrote: >>>>> >>>>>> Hi, >>>>>> >>>>>> "John Greenwood" <john.greenwood@bhpit.co.uk> wrote in message >>>>>> news:1j1er252pmquk9pi3786qocb32ahkqf38f@4ax.com... >>>>>>> Hi, >>>>>>> >>>>>>> I'm not sure if i'm misunderstanding how INotifyPropertyChanged >>>>>>> should >>>>>>> work but it's not working as I expected. >>>>>>> >>>>>>> I have a sample program with a very simple 'Customer' class with >>>>>>> three >>>>>>> properties code, name & address. All these are bound to a form via a >>>>>>> BindingSource and fire the PropertyChanged event when the property >>>>>>> is >>>>>>> modified. >>>>>>> >>>>>>> I change one of these properties in code and find that all of the >>>>>>> properties are fetched and rebound to the form. Is this correct ? >>>>>> Yes it is. Any property changed event will result in >>>>>> BindingManagerBase.PushData which causes a PushData on *all* its >>>>>> Bindings. >>>>>> >>>>>>> What's the point of specifying a property name in the >>>>>> When it comes to WinForms databinding there is no point afaik. But >>>>>> remember that INotifyPropertyChanged can be used elsewhere too, eg. >>>>>> for the PropertyGrid (dunno if it refreshes all properties on change >>>>>> there) and also for WPF (where it doesn't refresh all properties on >>>>>> change). >>>>>> >>>>>> HTH, >>>>>> Greetings >>>>>> >>>>>> >>>>>>> PropertyChangedEventArgs if all the controls are rebound anyway. >>>>>>> >>>>>>> Any help would be much appreciated >>>>>>> >>>>>>> John >>>>>>> >>>>>>> If it's any help my code is below >>>>>>> >>>>>>> using System; >>>>>>> using System.Collections.Generic; >>>>>>> using System.ComponentModel; >>>>>>> using System.Data; >>>>>>> using System.Drawing; >>>>>>> using System.Text; >>>>>>> using System.Windows.Forms; >>>>>>> >>>>>>> namespace NotifyChange >>>>>>> { >>>>>>> public partial class Form1 : Form >>>>>>> { >>>>>>> private Customer _customer; >>>>>>> >>>>>>> public Form1() >>>>>>> { >>>>>>> InitializeComponent(); >>>>>>> _customer = new Customer(); >>>>>>> _customer.Code = "G001"; >>>>>>> _customer.Name = "Greenwood Enterpises Ltd"; >>>>>>> _customer.Address = "128 Smithey Road"; >>>>>>> customerBindingSource.DataSource = _customer; >>>>>>> } >>>>>>> >>>>>>> private void button1_Click(object sender, EventArgs e) >>>>>>> { >>>>>>> Console.WriteLine("<-- Change Code --"); >>>>>>> >>>>>>> _customer.Code = "F001"; >>>>>>> >>>>>>> Console.WriteLine("-- Change Code -->"); >>>>>>> } >>>>>>> >>>>>>> private void button2_Click(object sender, EventArgs e) >>>>>>> { >>>>>>> Console.WriteLine("<-- Change Name --"); >>>>>>> >>>>>>> _customer.Name = "Fletcher Business Services Ltd"; >>>>>>> >>>>>>> Console.WriteLine("-- Change Name -->"); >>>>>>> } >>>>>>> >>>>>>> } >>>>>>> >>>>>>> public class Customer : INotifyPropertyChanged >>>>>>> { >>>>>>> >>>>>>> private string _code = ""; >>>>>>> private string _name = ""; >>>>>>> private string _address = ""; >>>>>>> >>>>>>> public string Code >>>>>>> { >>>>>>> get >>>>>>> { >>>>>>> Console.WriteLine("Got 'Code' at {0}", DateTime.Now); >>>>>>> return _code; >>>>>>> } >>>>>>> set >>>>>>> { >>>>>>> if (_code != value) >>>>>>> { >>>>>>> _code = value;
Cool. I'm glad you found a way to get it to work.
Robin S. --------------------------- [quoted text, click to view] "Doug Crawford" <webmail@nospam.com> wrote in message
news:uVQMyJCXHHA.2212@TK2MSFTNGP02.phx.gbl... > My "business object" is not really the traditional use case of a Customer > row in a database. It is more analogous to real time status data with > just one editable property. > > I did discover that if I toggle the value of the RaiseListChangedEvents > property on the BindingSource I can temporarily suppress change > notifications, so I think this approach will work. > > Doug > > RobinS wrote: >> I think the BeginEdit/EndEdit/CancelEdit methods could help you. I think >> BeginEdit applies to any control, not just to a DGV. >> >> What else is changing your data source? Is it the same user, or some >> other user? How are they changing your business object? >> >> You could also un-implement INotifyPropertyChanged; I don't know what >> other ramifications this would have, though. >> >> Robin S. >> --------------------------------------------- >> "Doug Crawford" <webmail@nospam.com> wrote in message >> news:us92M44WHHA.1180@TK2MSFTNGP05.phx.gbl... >>> Yes, if we follow the example in this thread I implemented >>> INotifyPropertyChanged on the Customer class. I did not implement >>> IEditableObject, but I am not sure that is going to help. My main >>> problem is that any change to an individual property in the Customer >>> class causes the binding mechanism to globally push all of the Customer >>> Properties to the Form controls (The property string name in the >>> PropertyChangedEventArgs appears to be ignored). >>> >>> So lets say you are editing Customer.Name in the DataGridView and while >>> you are editing something else changes Cusomter.Code in the data >>> source. I was hoping to just see the cell under the Code column change, >>> but actually all of the columns in the selected record are updated >>> including the cell I am currently editing. >>> >>> Maybe I should be implementing IEditableObject and prevent the Customer >>> class from triggering the PropertyChanged event until the edit is >>> complete. >>> >>> Will my Customer.BeginEdit() method be called when a user starts >>> editing a TextBox that is databound to a Customer property, or does >>> this mechanism only work with the DataGridView? >>> >>> Doug >>> >>> >>> >>> RobinS wrote: >>>> I'm assuming when you say you implemented INotifyPropertyChanged, you >>>> implemented it on the Customer Class. Did you also implement >>>> IEditableObject, and put in the code to save the original values, then >>>> populate them if the insert/udpate was cancelled? >>>> >>>> I have a DGV bound to a list of business objects and I'm not having >>>> any of these problems with it. >>>> >>>> Robin S. >>>> Ts'i mahnu uterna ot twan ot geifur hingts uto. >>>> ----------------------------------------------- >>>> "Doug Crawford" <webmail@nospam.com> wrote in message >>>> news:eiHC9buWHHA.4384@TK2MSFTNGP02.phx.gbl... >>>>> John Greenwood wrote: >>>>>> Hi Bart, >>>>>> >>>>>> Some of the properties on my class were totals built dynamically >>>>>> every >>>>>> time they were accessed and so of course were being rebuilt every >>>>>> time another property from the same class issued the change event. >>>>>> >>>>>> At least now I know and I can avoid similar situations in the >>>>>> future. >>>>>> >>>>>> Cheers >>>>>> >>>>>> John >>>>>> >>>>>> >>>>>> On Wed, 24 Jan 2007 15:28:43 GMT, "Bart Mermuys" >>>>>> <bmermuys.nospam@hotmail.com> wrote: >>>>>> >>>>>>> Hi, >>>>>>> >>>>>>> "John Greenwood" <john.greenwood@bhpit.co.uk> wrote in message >>>>>>> news:1j1er252pmquk9pi3786qocb32ahkqf38f@4ax.com... >>>>>>>> Hi, >>>>>>>> >>>>>>>> I'm not sure if i'm misunderstanding how INotifyPropertyChanged >>>>>>>> should >>>>>>>> work but it's not working as I expected. >>>>>>>> >>>>>>>> I have a sample program with a very simple 'Customer' class with >>>>>>>> three >>>>>>>> properties code, name & address. All these are bound to a form via >>>>>>>> a >>>>>>>> BindingSource and fire the PropertyChanged event when the >>>>>>>> property is >>>>>>>> modified. >>>>>>>> >>>>>>>> I change one of these properties in code and find that all of the >>>>>>>> properties are fetched and rebound to the form. Is this correct ? >>>>>>> Yes it is. Any property changed event will result in >>>>>>> BindingManagerBase.PushData which causes a PushData on *all* its >>>>>>> Bindings. >>>>>>> >>>>>>>> What's the point of specifying a property name in the >>>>>>> When it comes to WinForms databinding there is no point afaik. >>>>>>> But remember that INotifyPropertyChanged can be used elsewhere too, >>>>>>> eg. for the PropertyGrid (dunno if it refreshes all properties on >>>>>>> change there) and also for WPF (where it doesn't refresh all >>>>>>> properties on change). >>>>>>> >>>>>>> HTH, >>>>>>> Greetings >>>>>>> >>>>>>> >>>>>>>> PropertyChangedEventArgs if all the controls are rebound anyway. >>>>>>>> >>>>>>>> Any help would be much appreciated >>>>>>>> >>>>>>>> John >>>>>>>> >>>>>>>> If it's any help my code is below >>>>>>>> >>>>>>>> using System; >>>>>>>> using System.Collections.Generic; >>>>>>>> using System.ComponentModel; >>>>>>>> using System.Data; >>>>>>>> using System.Drawing; >>>>>>>> using System.Text; >>>>>>>> using System.Windows.Forms; >>>>>>>> >>>>>>>> namespace NotifyChange >>>>>>>> { >>>>>>>> public partial class Form1 : Form >>>>>>>> { >>>>>>>> private Customer _customer; >>>>>>>> >>>>>>>> public Form1() >>>>>>>> { >>>>>>>> InitializeComponent(); >>>>>>>> _customer = new Customer(); >>>>>>>> _customer.Code = "G001"; >>>>>>>> _customer.Name = "Greenwood Enterpises Ltd"; >>>>>>>> _customer.Address = "128 Smithey Road"; >>>>>>>> customerBindingSource.DataSource = _customer; >>>>>>>> } >>>>>>>> >>>>>>>> private void button1_Click(object sender, EventArgs e) >>>>>>>> { >>>>>>>> Console.WriteLine("<-- Change Code --"); >>>>>>>> >>>>>>>> _customer.Code = "F001"; >>>>>>>> >>>>>>>> Console.WriteLine("-- Change Code -->"); >>>>>>>> } >>>>>>>> >>>>>>>> private void button2_Click(object sender, EventArgs e) >>>>>>>> { >>>>>>>> Console.WriteLine("<-- Change Name --"); >>>>>>>> >>>>>>>> _customer.Name = "Fletcher Business Services Ltd"; >>>>>>>> >>>>>>>> Console.WriteLine("-- Change Name -->"); >>>>>>>> } >>>>>>>> >>>>>>>> } >>>>>>>> >>>>>>>> public class Customer : INotifyPropertyChanged >>>>>>>> { >>>>>>>> >>>>>>>> private string _code = ""; >>>>>>>> private string _name = ""; >>>>>>>> private string _address = ""; >>>>>>>>
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