ASP.NET EventHandling

Question

Hi,

I create a servercontrol for ASP.Net. For being short and precise I just list the things I do:

(1) Call EnsureChildControls in OnInit

(2) Create a dynamic table in CreateChildControls:

Table aTable = new Table();
aTable.ID = this.ID + "$" + T;
TableRow aRow = new TableRow();
aRow.ID = aTable.ID + "$R" + <COUNTER>.ToString();
TableCell aCell = new TableCell();

createLinkButton(row, col, caption, aCell, aRow.ID);

this.Controls.Add(aTable);

(3) Have a function like:

void aLinkButton_Command(object sender, CommandEventArgs e)
{
    // Some stuff
    return;
}

(4) Have a function like:

void createLinkButton(int row, int col, string caption, TableCell aCell, string baseID) {
    LinkButton lb = new LinkButton();
    lb.ID = baseID + "$" + row.ToString() + col.ToString();
    lb.Command += new CommandEventHandler(aLinkButton_Command);
    lb.Text = caption;
    lb.CommandName = "<command>";
    aCell.Controls.Add(lb);
    return;
}

But: The event is never called. The href is redered for postback, but the wired event never gets triggered.

No ideas anymore :(

Any ideas

Answer 1

Are you adding you table to the server controls .Controls collection, e.g.

this.Controls.Add(aTable);

Doesn't look like it from your code sample, so I expect this might be the problem

Answer 2

You will need to recreate the dynamically created LinkButton on Postback for it's associated EventHander to fire. Rather than explain the whole thing, I would highly recommend that you read Scott Mitchell's classic article on the subject.

Answer 3

I think implementing IPostBackEventHandler interface may help.

In your case you can implement Interface and in RisePostBackEvent you can call your event handler method.

Hope this helps !

Answer 4

Look at the page (.aspx file) where you are using the server control. Make sure that you are adding the control to the page's control tree on both initial requests and postback requests. All events are handled on postback requests and if the control that generated an event is not present during the postback, the event handler will never fire.