title: The name 'TextBox1' does not exist in the current context
body: <p>I get this error: <code>the name 'textbox1' does not exist in the current context</code></p>
  
  <p>My code:</p>
  
  <pre><code>namespace WebApplication19
  {
      public partial class Default:System.Web.UI.Page
  
      {
          protected void TextBox1_TextChanged(object sender, EventArgs e)
          {
              if (TextBox1.Text == "msc")
              {
                  RadioButton2.Visible = false;
                  DropDownList2.Visible = false;
              }
              else
              {
                  RadioButton1.Visible = false;
                  DropDownList1.Visible = false;
              }               
          }
      }
  }
  </code></pre>