TextBox遍历

 foreach (Control control in this.form1.Controls)
        {
            if (control.GetType().Name == "TextBox")
            {
                ((TextBox)control).Text = "KKK";
            }
        }
 foreach (object control in this.form1.Controls)
        {
            if (control is TextBox)
            {
                TextBox tb = (TextBox)control;
                tb.Text = "KKK";
            }
        }