title: How to change the readonly property false of textboxes in winform?
body: <p>How can we change the ReadOnly property of all textBoxes in a winform that is true to false i'm trying using this code but this prompt me object null reference error...</p>
  
  <pre><code>    private void TextBoxesReadOnlyTrue(Control.ControlCollection cc)
      {
          foreach (Control ctrl in cc)
          {
              TextBox tb = ctrl as TextBox;
              if (tb.ReadOnly)
               {
                  tb.ReadOnly = false;
               }
  
          }
      } 
  </code></pre>