Highlighting all user controls in an ASP.NET page - asp.net-2.0

Question

I want to highlight all user controls used in a page by adding a border around it. We are doing this to facilitate debugging. I could override RenderControl method in user control base class to do that easily but we have lot of user controls(legacy) that are not using base class.
I then took a different approach. I tried traversing page controls in PreRender method of page base class, which is used by all pages, and add a div with border to all user controls. But I found that it is not possible to add or remove from control collection if it contains code blocks (i.e. <% ... %>).
Any suggestions?
thanks

Answer 1

Here is how you can highlight an active input control that has the focus. You need to handle the onfocus and onblur client-side events of the input controls.and apply or remove the css style to the control by setting the controls className attribute
Add this to your css file:
.highlight
{
background-color: #fefbd2; /*highlight with yellow*/
color: #000080; /*make text blue*/
}
In your App_Code directory create a helper class like
public static class Helpers
{
/// <summary>
/// Adds the onfocus and onblur attributes to all input controls found in the specified parent,
/// to change their apperance with the control has the focus
/// </summary>
public static void SetInputControlsHighlight(Control container, string className, bool onlyTextBoxes)
{
foreach (Control ctl in container.Controls)
{
if ((onlyTextBoxes && ctl is TextBox) ||
(!onlyTextBoxes && (ctl is TextBox || ctl is DropDownList ||
ctl is ListBox || ctl is CheckBox || ctl is RadioButton ||
ctl is RadioButtonList || ctl is CheckBoxList)))
{
WebControl wctl = ctl as WebControl;
wctl.Attributes.Add("onfocus", string.Format("this.className = '{0}';", className));
wctl.Attributes.Add("onblur", "this.className = '';");
}
else
{
if (ctl.Controls.Count > 0)
SetInputControlsHighlight(ctl, className, onlyTextBoxes);
}
}
}
}
Then just override the OnLoad method of any page.
protected override void OnLoad(EventArgs e)
{
Helpers.SetInputControlsHighlight(this, "highlight", false);
base.OnLoad(e);
}