No button property is changed when a button is clicked: you get an event (the Button.Click event) so that you can do your thing when it happens.
Highlight your button, and look in the Properties pane of VS. Press the "lightning flash" button to show the available events, then double click on "Click" to add a handler.
The same thing happens with dynamic buttons, but you have to add the handler manually when you create them. VS can help: type your button creation code then type myButton.Click +=
Button myButton = new Button();
myButton.Click +=
Press [TAB] twice and it will be filled in for you.
"if the buttons are created by a dynamic button array,how can we identify a clicked button,among the other dynamic buttons in an array?"
Easy - it is handed to the Event handler as the "sender" parameter:
private void myButton_Click(object sender, EventArgs e)
{
Button pressed = sender as Button;
if (pressed != null)
{
}
}
The only reason to check for null is that it is possible to call event handlers directly: not advisable, but possible. If this happens (or the event is hooked to a different control type) then it will not throw an exception.