to convert string into TextBox control type
<p>to convert string in to TextBox type
i used following code</p>

<pre><code>protected void txtNumber_TextChanged(object sender, EventArgs e)
{
    int num = Convert.ToInt16(txtNumber.Text);
    for (int i = 1; i &lt;= num; i++)
    {
        String a = System.String.Concat("TextBox", i);

        TextBox dt1 =(TextBox)(this.FindControl(a);


    }
}
</code></pre>

<p>but in dt1 value remains null instead of 'a'.</p>
