ASP.Net: why is my button's click/command events not binding/firing in a repeater?

Question

Here's the code from the ascx that has the repeater:

<asp:Repeater ID="ListOfEmails" runat="server" >
    <HeaderTemplate><h3>A sub-header:</h3></HeaderTemplate>
    <ItemTemplate>
        [Some other stuff is here]
        <asp:Button ID="removeEmail" runat="server" Text="X" ToolTip="remove" />
    </ItemTemplate>
</asp:Repeater>

And in the codebehind for the repeater's databound and events:

Protected Sub ListOfEmails_ItemDataBound(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.RepeaterItemEventArgs) Handles ListOfEmails.ItemDataBound
    If (e.Item.ItemType = ListItemType.Item) Or (e.Item.ItemType = ListItemType.AlternatingItem) Then
        Dim removeEmail As Button = CType(e.Item.FindControl("removeEmail"), Button)
        removeEmail.CommandArgument = e.Item.ItemIndex.ToString()

        AddHandler removeEmail.Click, AddressOf removeEmail_Click
        AddHandler removeEmail.Command, AddressOf removeEmail_Command
    End If
End Sub

Sub removeEmail_Click(ByVal sender As Object, ByVal e As System.EventArgs)
    Response.Write("<h1>click</h1>")
End Sub

Sub removeEmail_Command(ByVal sender As Object, ByVal e As CommandEventArgs)
    Response.Write("<h1>command</h1>")
End Sub

Neither the click or command is getting called, what am I doing wrong?

Answer 1

Controls nested inside of Repeaters do not intercept events. Instead you need to bind to the Repeater.ItemCommand Event.

ItemCommand contains RepeaterCommandEventArgs which has two important fields:

• CommandName
• CommandArgument

So, a trivial example:

void rptr_ItemDataBound(object sender, RepeaterItemEventArgs e)
{
    if (e.Item.ItemType == ListItemType.AlternatingItem || e.Item.ItemType == ListItemType.Item)
    {
        // Stuff to databind
        Button myButton = (Button)e.Item.FindControl("myButton");

        myButton.CommandName = "Add";
        myButton.CommandArgument = "Some Identifying Argument";
    }
}

void rptr_ItemCommand(object source, RepeaterCommandEventArgs e)
{
    if (e.CommandName == "Add")
    {
        // Do your event
    }
}

Answer 2

You need to handle the ItemCommand event on your Repeater. Here's an example.

Then, your button clicks will be handled by the ListOfEmails_ItemCommand method. I don't think wiring up the Click or Command event (of the button) in ItemDataBound will work.

Answer 3

If you're planning to use ItemCommand event, make sure you register to ItemCommand event in Page_Init not in Page_Load.

protected void Page_Init(object sender, EventArgs e)
{
    // rptr is your repeater's name
    rptr.ItemCommand += new RepeaterCommandEventHandler(rptr_ItemCommand);
}

I am not sure why it wasn't working for me with this event registered in Page_Load but moving it to Page_Init helped.

Answer 4

Here's an experiment for you to try:

Set a breakpoint on ListOfEmails_ItemDataBound and see if it's being called for postbacks.

Answer 5

You know what's frustrating about this?

If you specify an OnClick in that asp:Button tag, the build will verify that the named method exists in the codebehind class, and report an error if it doesn't... even though that method will never get called.