Adding EventHandler to DropDownList programically

  • Thread starter Thread starter dtarczynski
  • Start date Start date
D

dtarczynski

Hello.
Im trying to add new EventHandler to DropDownList programically. Im
doing something like this:

DropDownList ddlCate = new DropDownList();
ddlCate.ID = String.Format("ddlCategory{0}", i++);
ddlCate.DataSource = tblSub1;
ddlCate.DataTextField =
tblSub1.Columns["categories_name"].ColumnName;
ddlCate.DataValueField =
tblSub1.Columns["categories_id"].ColumnName;
Panel1.Controls.Add(ddlCate);
ddlCate.DataBind();
ddlCate.AutoPostBack = true;
ddlCate.SelectedIndexChanged += new
System.EventHandler(BindCategories);

This is BindCategories function:

void BindCategories(object sender, EventArgs e)
{
Response.Write("Event raised!");

}

but when Im changing value in ddlCate BindCategories are not raised.
Any help?

thanks in advandce
Darek
 
My guess s that you have your code in a if (!Page.IsPostBack){}

since events happen on postback, they need to be setup during postback.
Normally you'd just place the hook during init...

onInit(object source, EventArgs e)
{
ddlCate.SelectedIndexChanged +=....
}

since it's dynamic, simply put it out side the !Page.IsPostback

Karl
 
Thanks for respose, but mayby you can answer me in more detail. Look
Karl. I have one DropDownList ddlCategories (I create it with
designer), then I have added code for SelectedItemIndexChanged. I have
to create another DropDownList when ddlCategories
SelectedItemIndexChanged is raised. All my code looks like this:

protected void Page_Load(object sender, EventArgs e)
{


}

protected void ddlCategories_SelectedIndexChanged(object sender,
EventArgs e)
{

if (...)
{
int i = 0;
DropDownList ddlCate = new DropDownList();
ddlCate.ID = String.Format("ddlCategory{0}", i++);
ddlCate.DataSource = tblSub1;
ddlCate.DataTextField =
tblSub1.Columns["categories_name"].ColumnName;
ddlCate.DataValueField =
tblSub1.Columns["categories_id"].ColumnName;
pnlCat.Controls.Add(ddlCate);
ddlCate.DataBind();
ddlCate.AutoPostBack = true;
ddlCate.SelectedIndexChanged += new
System.EventHandler(BindCategories);
}


}

void BindCategories(object sender, EventArgs e)
{
Response.Write("Event raised!");

}

Can you answer me, how to properly add this event handler please?

Karl Seguin [MVP] napisal(a):
 
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