Hi,

if you declare a public event on the control (e.g raise it from the
control). Page is capable to react to that event. E.g that happens on Page
level (Page and controls go the same request processing cycle and also are
in the somewhat spame phase when going through events related to request
processing, like On Init, Load, OnPrerender...)

For example you have

**
Public Event MyEvent As EventHandler
**
declared on control and you raise it by calling "RaiseEvent
MyEvent(Me,EventArgs.Empty)"

Page is capable to deal with it for example

**
Protected Sub MyControl_MyEvent(sender As Object, e As EventArgs) Handles
MyControl.MyEvent
....
End Sub
**
where MyControl would be the ID of your custom control.

--
Teemu Keiski
ASP.NET MVP, AspInsider
Finland, EU
http://blogs.aspadvice.com/joteke


[quoted text, click to view]

Using the Page property of the control to access Page level elements would be
a problem. For one I would have to use FindControl to access any of the
controls of the Page and even If I do that the scope context won't allow me
to change any properties of the control. Believe me I tried it! To add to the
problems any variables of the Page would not be recognized within the
webcontrol at compile time. As far as getting the Response object I know I
can use the System.Web.HttpContext.Current to get to it. But the main reason
I should the error was to demonstrate that the scope context of the event
call is still within the webcontrol. If I call a public method of the
webcontrol that then calls the delegate event that references the Page level
event handler all controls and variables are accessible.

Here is a sample of code of the webcontrol, there is much more but I think
you'll get an idea as to what is happening:

[System.Security.Permissions.PermissionSet(System.Security.Permissions.SecurityAction.Demand, Name="FullTrust"), DefaultProperty(""),
ToolboxData("<{0}:SelectsDisplay runat=server></{0}:SelectsDisplay>")]
public class SelectsDisplay : System.Web.UI.WebControls.WebControl,
IPostBackEventHandler, IPostBackDataHandler
{
private string pageName;
private string connStr;
public string diag = "";
private bool depthasfired = false;
protected System.Web.UI.WebControls.DropDownList lstProjects;
protected System.Web.UI.WebControls.DropDownList lstDepartments;
protected System.Web.UI.WebControls.DropDownList lstCompanies;
protected System.Web.UI.HtmlControls.HtmlTable BarDisplay;
protected System.Web.UI.WebControls.DropDownList lstTeams;
protected System.Web.UI.WebControls.DropDownList lstLocations;
public event oBarDropEventHandler proSelect;
public event oBarDropEventHandler deptSelect;
public event oBarDropEventHandler compSelect;
public event oBarDropEventHandler locSelect;
public event oBarDropEventHandler teamSelect;

protected override void
Render(HtmlTextWriter output)
{
BarDisplay.RenderControl(output);

}

public void InitializeComponent()
{
lstProjects = new
DropDownList();
this.Controls.Add(lstProjects);
lstDepartments = new DropDownList();
this.Controls.Add(lstDepartments);
lstCompanies = new DropDownList();
this.Controls.Add(lstCompanies);
BarDisplay = new HtmlTable();
this.Controls.Add(BarDisplay);
lstTeams = new DropDownList();
this.Controls.Add(lstTeams);
lstLocations = new DropDownList();
this.Controls.Add(lstLocations);

this.lstLocations.SelectedIndexChanged += new
System.EventHandler(this.lstLocations_SelectedIndexChanged);
this.lstCompanies.SelectedIndexChanged += new
System.EventHandler(this.lstCompanies_SelectedIndexChanged);
this.lstDepartments.SelectedIndexChanged += new
System.EventHandler(this.lstDepartments_SelectedIndexChanged);
this.lstProjects.SelectedIndexChanged += new
System.EventHandler(this.lstProjects_SelectedIndexChanged);
this.lstTeams.SelectedIndexChanged += new
System.EventHandler(this.lstTeams_SelectedIndexChanged);
this.Load += new System.EventHandler(this.loadDisplay);
}

//Local event handler in webcontrol
private void
lstLocations_SelectedIndexChanged(object sender, System.EventArgs e)
{

if(lstLocations.SelectedIndex != 0)
lstCompanies.Enabled = true;
else
lstCompanies.Enabled = false;
getCompanies();
oBarSelectEventArgs E = new
oBarSelectEventArgs(lstLocations.SelectedValue);
//fires delegate event to Page
if(locSelect != null)
locSelect(this,E);

}

}

//Custom EventArgs class
public class oBarSelectEventArgs : EventArgs
{
private string SelectedValue = "";
// Constructor.
public oBarSelectEventArgs(string selectedValue) {SelectedValue =
selectedValue;}
// Properties.
public string SelectItem{ get { return SelectedValue;}}
}


public delegate void oBarDropEventHandler(object sender,
oBarSelectEventArgs e);


[quoted text, click to view]