How to handle custom Events?

[LochDhu]

Members,

Default.aspx has an HTML Button that opens Page2.aspx in a new frame, I need the user to set some params and then have Default.aspx post back and do something with the params. I am using window.opener to get Default.aspx to postback. The problem is creating my own Events to capture. I *think* I need to create a class that inherits from Control - I won't have a visual appearance to my control, I just need to define my own Events with my own EventArgs - and I need to learn how to specify which one of my events to handle on PostBack.

Are their tutorials on this? I have a few books but they do not go into details on this. I'm sure this has been done before.

Any comments greatly appreciated.

Scott

 

[BoulderBum]

This should get you started:

http://msdn.microsoft.com/library/d...y/en-us/cpguide/html/cpconeventsdelegates.asp

 

[BoulderBum]

If you have questions, let me know.

 

[cappmgr]

Scott how you making it on this? I though the post interesting so I wrote a stub to envoke my own event with it's own EventArgs. i'd be interested how you solved your issue. This uses a button click event to fire the control which will envoke the event.
BoulderBum or anyone else any thoughts appreciated.
Marty
The control.

using System;
using System.Web;	
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;

namespace ControlLibrary1
{
	/// <summary>
	/// Summary description for MessageControl.
	/// </summary>
	public class MessageControl : Control, INamingContainer
	{

		Label lblSendMessage;

		public delegate void SendMessageEventHandler(object sender, MessageEventArgs e);

		public event SendMessageEventHandler SendMessage;

		public void OnSetAndSendMessage(Object sender, EventArgs e)
		{
			lblSendMessage.Text = "You pressed the button which fires the event.";
			MessageEventArgs messageArgs = new MessageEventArgs();
			messageArgs.Message = "This message is from the SendMessage Event in the Control that has just been fired.";
			messageArgs.ShowMessage = true;
			//envoke our EventHandler
			SendMessage(this, messageArgs);
		}

		public void Page_Load(object src, EventArgs e)
		{
			EnsureChildControls();
		}

		protected override void CreateChildControls()
		{
			Button btnSend = new Button();
			btnSend.Text = "Fire Event";
			btnSend.Click += new EventHandler(this.OnSetAndSendMessage);
			Controls.Add(btnSend);
			Controls.Add(new LiteralControl("<br/>"));
			lblSendMessage = new Label();
			Controls.Add(lblSendMessage);

		}	
	}
//	This is a class derived from EventArgs that should be encapsulated but we left it 
//  in here as this is a proof of concept.
//  The EventArgs that are used in the Custom Event SendMessage
	public class MessageEventArgs : System.EventArgs
	{
		private string sMessage;
		public String Message
		{
			get { return(sMessage);	}
			set	{ sMessage = value; }
		}  
		
		private bool bShowMessage;
		public bool ShowMessage
		{
			get { return(bShowMessage);	}
			set	{ bShowMessage = value; }
		}  
	}
}

The aspx.cs that uses the control

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;

namespace CSTestWebForms
{
	/// <summary>
	/// Summary description for TestMessageEventArgs.
	/// </summary>
	public class TestMessageEventArgs : System.Web.UI.Page
	{
		protected ControlLibrary1.MessageControl MyCtrl;
		protected System.Web.UI.WebControls.Label Label1;
	
		private void Page_Load(object sender, System.EventArgs e)
		{
			// Put user code to initialize the page here
		}

		public void MyCtrl_OnSendMessage(object sender, ControlLibrary1.MessageEventArgs e)
		{
			if (e.ShowMessage)
			{
				Label1.Text = e.Message;
			}
			else
			{
				Label1.Text = "Control did not send a message";
			}
		}
		#region Web Form Designer generated code
		override protected void OnInit(EventArgs e)
		{
			//
			// CODEGEN: This call is required by the ASP.NET Web Form Designer.
			//
			InitializeComponent();
			base.OnInit(e);
		}
		
		/// <summary>
		/// Required method for Designer support - do not modify
		/// the contents of this method with the code editor.
		/// </summary>
		private void InitializeComponent()
		{    
			this.Load += new System.EventHandler(this.Page_Load);
			MyCtrl.SendMessage += new ControlLibrary1.MessageControl.SendMessageEventHandler(this.MyCtrl_OnSendMessage);
		}
		#endregion
	}
}

the aspx

<%@ Register TagPrefix="cc1" Namespace="ControlLibrary1" Assembly="ControlLibrary1" %>
<%@ Page language="c#" Codebehind="TestMessageEventArgs.aspx.cs" AutoEventWireup="false" Inherits="CSTestWebForms.TestMessageEventArgs" %>
<HTML>
	<HEAD>
	</HEAD>
	<body>
		<form id="Form1" runat="server">
			<CC1:MESSAGECONTROL id="MyCtrl" runat="server"></CC1:MESSAGECONTROL>
			<br>
			<asp:label id="Label1" runat="server">Label1</asp:label>
		</form>
	</body>
</HTML>

 

[LochDhu]

Thanks for the sample code. I have made some progress and actually got it to work. Here is the code for my Control:

Imports System.ComponentModel
Imports System.Web.UI
Imports System
Imports System.Web.UI.Control


<ToolboxData("<{0}:DWSDGeocode runat=server></{0}:DWSDGeocode>")> Public Class DWSDGeocode
    Inherits System.Web.UI.Control
    Implements IPostBackEventHandler
    Implements INamingContainer

    Public Event MapLocation As EventHandler

    Protected Overridable Sub OnMapLocation(ByVal e As GeocodeEventArgs)
        RaiseEvent MapLocation(Me, e)
    End Sub

    Public Overridable Sub RaisePostBackEvent(ByVal eventArgument As String) _
      Implements IPostBackEventHandler.RaisePostBackEvent
        OnMapLocation(New GeocodeEventArgs(eventArgument))
    End Sub



    Public Class GeocodeEventArgs
        Inherits EventArgs
        Private _Coordinates As String
        Private _XCoordinate As Double
        Private _YCoordinate As Double

        Public GeocodeEventArgs()

        Public Property Coordinates() As String
            Get
                Return _Coordinates
            End Get
            Set(ByVal Value As String)
                _Coordinates = Value.ToString
            End Set
        End Property

        Public Property XCoordinate() As Double
            Get
                Return _XCoordinate
            End Get
            Set(ByVal Value As Double)
                _XCoordinate = Value
            End Set
        End Property

        Public Property YCoordinate() As Double
            Get
                Return _YCoordinate
            End Get
            Set(ByVal Value As Double)
                _YCoordinate = Value
            End Set
        End Property

        Public Sub New(ByVal Coords As String)
            _Coordinates = Coords
            'ParseCoordinates()
        End Sub

        Private Sub ParseCoordinates()
            Dim split As String() = Nothing
            split = _Coordinates.Split(",")
            _XCoordinate = CType(split(0), Double)
            _YCoordinate = CType(split(1), Double)
        End Sub

    End Class

End Class

I'm still trying to learn all the caveats of this, I didn't realize how much work it was.