The problem could appear if you use other validation controls and one of them is not verified. It is difficult to say what could be the issue, so can run your code in debbuger to figure out where the problems is. You could give a try to something like this in the code behind. I had a similar problem when did not use Page.IsValid
| protected void button1_Click1(object sender, EventArgs e)
| //Gets a value indicating whether page validation succeeded.
| if (this.Page.IsValid)
| //do something
| Label1.Text = textbox1.Text;
If you want you could share your code and approach with us.
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