ASP.NET Tutorial/Custom Controls/PostBack

Adding PostBack capabilities to a server control (C#)

   <source lang="csharp">

using System.ruponentModel; using System.Text; using System.Web.UI; using System.Web.UI.WebControls; namespace WebControlLibrary1 {

   [DefaultProperty("Text")]
   [ToolboxData("<{0}:WebCustomControl3 runat=server></{0}:WebCustomControl3>")]
   public class WebCustomControl3 : WebControl
   {
       protected override void Render(HtmlTextWriter output)
       {
           PostBackOptions p = new PostBackOptions(this);
           output.AddAttribute(HtmlTextWriterAttribute.Onclick,
               Page.ClientScript.GetPostBackEventReference(p));
           output.AddAttribute(HtmlTextWriterAttribute.Value, "My Button");
           output.AddAttribute(HtmlTextWriterAttribute.Id, this.ClientID);
           output.AddAttribute(HtmlTextWriterAttribute.Name, this.ClientID);
           output.RenderBeginTag(HtmlTextWriterTag.Button);
           output.RenderEndTag();
       }
   }

}</source>

Adding PostBack capabilities to a server control (VB)

   <source lang="csharp">

Imports System.ruponentModel Imports System.Web.UI <DefaultProperty("Text")> _ <ToolboxData("<{0}:WebCustomControl3 runat=server></{0}:WebCustomControl3>")> _ Public Class WebCustomControl3

   Inherits System.Web.UI.WebControls.WebControl
   Protected Overrides Sub Render(ByVal output As System.Web.UI.HtmlTextWriter)
       Dim p As New PostBackOptions(Me)
       output.AddAttribute(HtmlTextWriterAttribute.Onclick, _
           Page.ClientScript.GetPostBackEventReference(p))
       output.AddAttribute(HtmlTextWriterAttribute.Value, "My Button")
       output.AddAttribute(HtmlTextWriterAttribute.Id, Me.ClientID)
       output.AddAttribute(HtmlTextWriterAttribute.Name, Me.ClientID)
       output.RenderBeginTag(HtmlTextWriterTag.Button)
       output.RenderEndTag()
   End Sub

End Class</source>

Handling postback events in a server control (C#)

   <source lang="csharp">

using System.ruponentModel; using System.Text; using System.Web.UI; using System.Web.UI.WebControls; namespace WebControlLibrary1 {

   [DefaultProperty("Text")]
   [ToolboxData("<{0}:WebCustomControl3 runat=server></{0}:WebCustomControl3>")]
   public class WebCustomControl3 : WebControl, IPostBackEventHandler
   {
       protected override void Render(HtmlTextWriter output)
       {
           PostBackOptions p = new PostBackOptions(this);
           output.AddAttribute(HtmlTextWriterAttribute.Onclick,Page.ClientScript.GetPostBackEventReference(p));
           output.AddAttribute(HtmlTextWriterAttribute.Value, "My Button");
           output.AddAttribute(HtmlTextWriterAttribute.Id, this.ClientID);
           output.AddAttribute(HtmlTextWriterAttribute.Name, this.ClientID);
           output.RenderBeginTag(HtmlTextWriterTag.Button);
           output.RenderEndTag();
       }
       #region IPostBackEventHandler Members
       public event EventHandler Click;
       public virtual void OnClick(EventArgs e)
       {
           if (Click != null)
           {
               Click(this, e);
           }
       }
       public void RaisePostBackEvent(string eventArgument)
       {
           OnClick(EventArgs.Empty);
       }
       #endregion
   
   }

}</source>

Handling postback events in a server control (VB)

   <source lang="csharp">

Imports System.ruponentModel Imports System.Web.UI <DefaultProperty("Text")> _ <ToolboxData("<{0}:WebCustomControl3 runat=server></{0}:WebCustomControl3>")> _ Public Class WebCustomControl3

   Inherits System.Web.UI.WebControls.WebControl
   Implements IPostBackEventHandler
   Protected Overrides Sub Render(ByVal output As System.Web.UI.HtmlTextWriter)
       Dim p As New PostBackOptions(Me)
       output.AddAttribute(HtmlTextWriterAttribute.Onclick, _
           Page.ClientScript.GetPostBackEventReference(p))
       output.AddAttribute(HtmlTextWriterAttribute.Value, "My Button")
       output.AddAttribute(HtmlTextWriterAttribute.Id, Me.ClientID)
       output.AddAttribute(HtmlTextWriterAttribute.Name, Me.ClientID)
       output.RenderBeginTag(HtmlTextWriterTag.Button)
       output.RenderEndTag()
   End Sub
   Public Event Click()
   Public Sub OnClick(ByVal args As EventArgs)
       RaiseEvent Click()
   End Sub
   Public Sub RaisePostBackEvent(ByVal eventArgument As String) Implements System.Web.UI.IPostBackEventHandler.RaisePostBackEvent
       OnClick(EventArgs.Empty)
   End Sub

End Class</source>