|
|
You're in the
asp.net building controls
group:Templated data-bound server control design question
asp.net building controls:
which you use for instantiating (presentation layer) templates. -- John Saunders Internet Engineer john.saunders@surfcontrol.com [quoted text, click to view] "joe_s" <dontmail@localhost> wrote in message news:uFVc1TjUDHA.1012@TK2MSFTNGP11.phx.gbl... > Hello, > I am working on an n-tier .NET application. The presentation is through aspx > pages and custom data-bound server controls which use templates to separate > interface from content. > > In all the samples I've seen regarding such controls, the templates are > instantiated in a class which inherits [Web]Control and implements > INamingContainer (here's the QuickStart source which demonstrates this: > http://samples.gotdotnet.com/quickstart/util/srcview.aspx?path=/quickstart/a > spplus/samples/webforms/ctrlauth/templates/Repeater2.src&file=CS\Repeater2.c > s&font=3). This class has all the properties which will eventually be shown > on the page. What I want to know is if there is a way to accomplish the same > thing without this class. > > This might seem strange, but the reason I'd like to do this, is that I've > already got a class with the same properties in my business logic layer, and > I don't want to create another almost identical class. It would make > maintenance a nightmare. I can't use this class directly in the > ITemplate.InstantiateIn() method because it does not inherit Control, or > implement any interface, and it shouldn't. > > I hope I made myself clear. If you have any suggestions or questions, please > do not hesitate to reply. > > Thank you, > Joe > > > >
Joe, simply have your CarItem class hold a reference to a Car instead of
duplicating all the properties: foreach(Car car in cc) { if (ItemTemplate != null) { CarItem ci = new CarItem(car); ItemTemplate.InstantiateIn(ci); } } ... class CarItem : Control, INamingContainer { private Car m_Car; public CarItem(Car car) { m_Car = car; } public Car DataItem { get {return m_Car;} } } .... Your templates can then reference DataBinder.Evan(Container.DataItem, "Manufacturer"); BTW, I'd separate the database access from the control. Give the control a DataSource property of type CarCollection and let the page developer decide what sort of car collection is wanted. You might even make the DataSource property of type IEnumerable and let the control check at runtime whether the enumerated items happen to be of type Car (or some derived class thereof). That would allow you to use other collection types in the future - a HashTable of cars, keyed on Owner, for instance. -- John Saunders Internet Engineer john.saunders@surfcontrol.com [quoted text, click to view] "joe_s" <dontmail@localhost> wrote in message news:uP5EsojUDHA.2312@TK2MSFTNGP12.phx.gbl... > I am not using that class, I can't because it doesn't inherit Control and > implement INamingContainer, and I know I shouldn't. > > If you check out that link, you'll see that there is a class > (RepeaterItem.cs) which defines a data item with the data that will be > displayed on the page. If I implement my control in this way, I would need > to create such a class, but it would be virtually identical to my BL class, > except for the inheritance. Just to illustrate, here's an example: > > // BL layer > class Car > { > int id; > string manufacturer; > string model; > > // get/set properties here > } > > public class CarCollection : ArrayList > { > public CarCollection() : base() {} > public CarCollection(ICollection c) : base(c) {} > } > > class DBProcs > { > public CarCollection GetCarsFromDB() > { > CarCollection cc = new CarCollection(); > // get data from db and fill the collection with Car objects // > return cc; > } > } > > Let's say I want to display these items in by using a server control as I > explained in the original post. I would need to create the following class > in the presentation layer > > // presentation > class CarItem : Control, INamingContainer > { > // everything's same as in the Car class above > // bad for maintenance > } > > class MyServerControl : Control, INamingContainer > { > ... > protected override void OnDataBinding(EventArgs e) > { > CarCollection cc = new CarCollection(); > cc = GetCarsFromDB(); > ... > foreach(Car car in cc) > { > // I want to avoid the following > CarItem ci = new CarItem(); > ci.Model = car.Model; > ci.Manufacturer = car.Manufacturer; > > ItemTemplate.InstantiateIn(ci); > ... > } > ... > } > ... > } > > The syntax may not be 100% correct, but I hope you understand my problem > now. > > "John Saunders" <john.saunders@surfcontrol.com> wrote in message > news:Ov$sEbjUDHA.2568@tk2msftngp13.phx.gbl... > > Perhaps you should explain why you have a class in your business logic > layer > > which you use for instantiating (presentation layer) templates. > > > > -- > > John Saunders > > Internet Engineer > > john.saunders@surfcontrol.com > > > > > > "joe_s" <dontmail@localhost> wrote in message > > news:uFVc1TjUDHA.1012@TK2MSFTNGP11.phx.gbl... > > > Hello, > > > I am working on an n-tier .NET application. The presentation is through > > aspx > > > pages and custom data-bound server controls which use templates to > > separate > > > interface from content. > > > > > > In all the samples I've seen regarding such controls, the templates are > > > instantiated in a class which inherits [Web]Control and implements > > > INamingContainer (here's the QuickStart source which demonstrates this: > > > > > > http://samples.gotdotnet.com/quickstart/util/srcview.aspx?path=/quickstart/a > > > > > > spplus/samples/webforms/ctrlauth/templates/Repeater2.src&file=CS\Repeater2.c > > > s&font=3). This class has all the properties which will eventually be > > shown > > > on the page. What I want to know is if there is a way to accomplish the > > same > > > thing without this class. > > > > > > This might seem strange, but the reason I'd like to do this, is that > I've > > > already got a class with the same properties in my business logic layer, > > and > > > I don't want to create another almost identical class. It would make > > > maintenance a nightmare. I can't use this class directly in the > > > ITemplate.InstantiateIn() method because it does not inherit Control, or > > > implement any interface, and it shouldn't. > > > > > > I hope I made myself clear. If you have any suggestions or questions, > > please > > > do not hesitate to reply. > > > > > > Thank you, > > > Joe > > > > > > > > > > > > > > > > > >
Hello,
I am working on an n-tier .NET application. The presentation is through aspx pages and custom data-bound server controls which use templates to separate interface from content. In all the samples I've seen regarding such controls, the templates are instantiated in a class which inherits [Web]Control and implements INamingContainer (here's the QuickStart source which demonstrates this: http://samples.gotdotnet.com/quickstart/util/srcview.aspx?path=/quickstart/a spplus/samples/webforms/ctrlauth/templates/Repeater2.src&file=CS\Repeater2.c s&font=3). This class has all the properties which will eventually be shown on the page. What I want to know is if there is a way to accomplish the same thing without this class. This might seem strange, but the reason I'd like to do this, is that I've already got a class with the same properties in my business logic layer, and I don't want to create another almost identical class. It would make maintenance a nightmare. I can't use this class directly in the ITemplate.InstantiateIn() method because it does not inherit Control, or implement any interface, and it shouldn't. I hope I made myself clear. If you have any suggestions or questions, please do not hesitate to reply. Thank you, Joe
I am not using that class, I can't because it doesn't inherit Control and
implement INamingContainer, and I know I shouldn't. If you check out that link, you'll see that there is a class (RepeaterItem.cs) which defines a data item with the data that will be displayed on the page. If I implement my control in this way, I would need to create such a class, but it would be virtually identical to my BL class, except for the inheritance. Just to illustrate, here's an example: // BL layer class Car { int id; string manufacturer; string model; // get/set properties here } public class CarCollection : ArrayList { public CarCollection() : base() {} public CarCollection(ICollection c) : base(c) {} } class DBProcs { public CarCollection GetCarsFromDB() { CarCollection cc = new CarCollection(); // get data from db and fill the collection with Car objects // return cc; } } Let's say I want to display these items in by using a server control as I explained in the original post. I would need to create the following class in the presentation layer // presentation class CarItem : Control, INamingContainer { // everything's same as in the Car class above // bad for maintenance } class MyServerControl : Control, INamingContainer { ... protected override void OnDataBinding(EventArgs e) { CarCollection cc = new CarCollection(); cc = GetCarsFromDB(); ... foreach(Car car in cc) { // I want to avoid the following CarItem ci = new CarItem(); ci.Model = car.Model; ci.Manufacturer = car.Manufacturer; ItemTemplate.InstantiateIn(ci); ... } ... } ... } The syntax may not be 100% correct, but I hope you understand my problem now. [quoted text, click to view] "John Saunders" <john.saunders@surfcontrol.com> wrote in message news:Ov$sEbjUDHA.2568@tk2msftngp13.phx.gbl... > Perhaps you should explain why you have a class in your business logic layer > which you use for instantiating (presentation layer) templates. > > -- > John Saunders > Internet Engineer > john.saunders@surfcontrol.com > > > "joe_s" <dontmail@localhost> wrote in message > news:uFVc1TjUDHA.1012@TK2MSFTNGP11.phx.gbl... > > Hello, > > I am working on an n-tier .NET application. The presentation is through > aspx > > pages and custom data-bound server controls which use templates to > separate > > interface from content. > > > > In all the samples I've seen regarding such controls, the templates are > > instantiated in a class which inherits [Web]Control and implements > > INamingContainer (here's the QuickStart source which demonstrates this: > > > http://samples.gotdotnet.com/quickstart/util/srcview.aspx?path=/quickstart/a > > > spplus/samples/webforms/ctrlauth/templates/Repeater2.src&file=CS\Repeater2.c > > s&font=3). This class has all the properties which will eventually be > shown > > on the page. What I want to know is if there is a way to accomplish the > same > > thing without this class. > > > > This might seem strange, but the reason I'd like to do this, is that I've > > already got a class with the same properties in my business logic layer, > and > > I don't want to create another almost identical class. It would make > > maintenance a nightmare. I can't use this class directly in the > > ITemplate.InstantiateIn() method because it does not inherit Control, or > > implement any interface, and it shouldn't. > > > > I hope I made myself clear. If you have any suggestions or questions, > please > > do not hesitate to reply. > > > > Thank you, > > Joe > > > > > > > > > >
Wow, that's very simple. I don't know what I was thinking.
As for separating database access, that's exactly what I've done, the code below was just quickly put together to illustrate the problem. Thank you very much for your help, John. [quoted text, click to view] "John Saunders" <john.saunders@surfcontrol.com> wrote in message news:uHyJIyjUDHA.2368@TK2MSFTNGP09.phx.gbl... > Joe, simply have your CarItem class hold a reference to a Car instead of > duplicating all the properties: > > foreach(Car car in cc) > { > if (ItemTemplate != null) > { > CarItem ci = new CarItem(car); > ItemTemplate.InstantiateIn(ci); > } > } > .. > > class CarItem : Control, INamingContainer > { > private Car m_Car; > > public CarItem(Car car) > { > m_Car = car; > } > > public Car DataItem > { > get {return m_Car;} > } > } > ... > > Your templates can then reference DataBinder.Evan(Container.DataItem, > "Manufacturer"); > > > BTW, I'd separate the database access from the control. Give the control a > DataSource property of type CarCollection and let the page developer decide > what sort of car collection is wanted. You might even make the DataSource > property of type IEnumerable and let the control check at runtime whether > the enumerated items happen to be of type Car (or some derived class > thereof). That would allow you to use other collection types in the future - > a HashTable of cars, keyed on Owner, for instance. > -- > John Saunders > Internet Engineer > john.saunders@surfcontrol.com
Don't see what you're looking for? Try a search.
|
June 2003
July 2003
August 2003
September 2003
October 2003
November 2003
December 2003
January 2004
February 2004
March 2004
April 2004
May 2004
June 2004
July 2004
August 2004
September 2004
October 2004
November 2004
December 2004
January 2005
February 2005
March 2005
April 2005
May 2005
June 2005
July 2005
August 2005
September 2005
October 2005
November 2005
December 2005
January 2006
February 2006
March 2006
April 2006
May 2006
June 2006
July 2006
August 2006
September 2006
October 2006
November 2006
December 2006
January 2007
February 2007
March 2007
April 2007
May 2007
June 2007
July 2007
August 2007
September 2007
October 2007
November 2007
December 2007
January 2008
February 2008
March 2008
April 2008
May 2008
June 2008
| home · blog · groups | Questions? Comments? Contact the dn |