在Page_Load 中判断是哪个控件触发了postback(Detect in Page_Load which control caused a postback)

Private   Function  DidControlCausePostBack( ByVal  uniqueID  As   String )  As   Boolean

         Dim  bool  As   Boolean   =   False

        bool  =  ( Not  Request.Form(uniqueID)  Is   Nothing )  OrElse  ( Not  Request.Form( " __EVENTTARGET " )  Is   Nothing   AndAlso  Request.Form( " __EVENTTARGET " ).Equals(uniqueID))  OrElse  (( Not  Request.Form(uniqueID  &   " .x " )  Is   Nothing )  AndAlso  ( Not  Request.Form(uniqueID  &   " .y " )  Is   Nothing ))

         Return  bool

     End Function

private   bool  DidControlCausePostBack( string  uniqueID)
{

  return  ( ! (Request.Form[uniqueID]  ==   null ))  ||  ( ! (Request.Form[ " __EVENTTARGET " ]  ==   null )  &&  Request.Form[ " __EVENTTARGET " ].Equals(uniqueID))  ||  (( ! (Request.Form[uniqueID  +   " .x " ]  ==   null ))  &&  ( ! (Request.Form[uniqueID  +   " .y " ]  ==   null )));
}

Protected   WithEvents  LinkButton1  As  System.Web.UI.WebControls.LinkButton
Protected   WithEvents  ImageButton1  As  System.Web.UI.WebControls.ImageButton
Protected   WithEvents  Button1  As  System.Web.UI.WebControls.Button

     Private   Sub  Page_Load( ByVal  sender  As  System.Object,  ByVal  e  As  System.EventArgs)  Handles   MyBase .Load

         If  DidControlCausePostBack(Button1.UniqueID)  Then
            Response.Write( " Button1 " )
         End   If

         If  DidControlCausePostBack(LinkButton1.UniqueID)  Then
            Response.Write( " LinkButton1 " )
         End   If

         If  DidControlCausePostBack(ImageButton1.UniqueID)  Then
            Response.Write( " ImageButton1 " )
         End   If

     End Sub

该方法仅对Buttons, LinkButtons and ImageButtons有效
From: http://aspadvice.com/blogs/joteke/archive/2004/08/05/2288.aspx