Friday, April 3, 2009

Find Post back Control ID

Find Post back Control in the Asp.net Page c#

This is a simple code to retrive the control id to identify which control is causing the postback.

Infact from
* Page.Request.Params["__EVENTTARGET"] and
* Page.Request.Params["__EVENTARGUMENT"] we can identify the arguments too.




public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (IsPostBack)
Response.Write(getPostBackControlName());
}






private string getPostBackControlName()
{
Control control = null;
//first we will check the "__EVENTTARGET" because if post back made by the controls
//which used "_doPostBack" function also available in Request.Form collection.
string ctrlname = Page.Request.Params["__EVENTTARGET"];
if (ctrlname != null && ctrlname != String.Empty)
{
control = Page.FindControl(ctrlname);
}
// if __EVENTTARGET is null, the control is a button type and we need to
// iterate over the form collection to find it
else
{
string ctrlStr = String.Empty;
Control c = null;
foreach (string ctl in Page.Request.Form)
{
//handle ImageButton they having an additional "quasi-property" in their Id which identifies
//mouse x and y coordinates
if (ctl.EndsWith(".x") || ctl.EndsWith(".y"))
{
ctrlStr = ctl.Substring(0, ctl.Length - 2);
c = Page.FindControl(ctrlStr);
}
else
{
c = Page.FindControl(ctl);
}
if (c is System.Web.UI.WebControls.Button ||
c is System.Web.UI.WebControls.ImageButton)
{
control = c;
break;
}
}
}
if(control!=null)
// return control.ID; // for simple page without any masterpage.
return control.UniqueID; // where its a contentpage and if master page is there
else
return "";


}
}



Source :
http://geekswithblogs.net/mahesh/archive/2006/06/27/83264.aspx