`PlaceHolder` control forgets everything that it had on each postback (Stateless behavior). You have to `remember` it instead. Following code works: Int32 TextBoxCount { get { if (ViewState["TextBoxCount"] == n...

It can be done by adding a handler to following events: UIElement.KeyUpEvent UIElement.KeyDownEvent UIElement.MouseLeftButtonDownEvent UIElement.MouseLeftButtonUpEvent UIElement.MouseWheelEvent UIElement.TextInputEvent ...

Closures at work here. Simply creating a local copy of "var c" **inside** the loop will solve the issue. public sealed class SomeType { public event EventHandler Triggered; public void Trigger() { // u...