Event handler not fired for dynamically created controls

Event handling is done by ASP.NET by matching up control's ID & the request parameters. In your case, the TextBox created during txtTextChanged() will have an auto ID because you don't specify any explicit ID. That ID will be posted back during the text changed event.

After page load event, ASP.NET will try to find a control with such ID to fire the event for it. Obviously ASP.NET won't be able to find the match because the TextBox created during Page_Load() is different and would have different ID.

To solve this: specify an explicit ID for your textbox:

TextBox txt = new TextBox();txt.Text = myText;txt.ID = "txtBox";

Try creating the controls in the Page_Init() method ...

for a postback event to fire, the control that should fire the event needs to be available with the same id and the same data on the postback lifecycle.

If you have static controls (defined in your aspx/ascx/master) and viewstate turned on, then they will be recreated automagically.

If you don't want to use viewstate, or use dynamic controls, you need to databind controls on each page_load, so that the controls are up and running in time for events to fire (happens after Page_load)

if you change the ID of a parent control, or page, you might accidentally throw off the viewstate autobind, as the control IDs contains ancestors IDs. I think you should be safe doing that, so long as you do it in Page_Init (before viewstate is set up)