Question

I have a Web content form and need to access a control inside the content panel. I know of two ways to access the control:

1. TextBox txt = (TextBox)Page.Controls[0].Controls[3].Controls[48].Controls[6]
2. By writing a recursive function that searches through all controls.

Is there any other easier way, since Page.FindControl doesn’t work in this instance. The reason I am asking is it feels to me like the Page object or the Content Panel object should have a method to find a child control, but can’t find anything like it.

Answer 1

The issue is that FindControl() does not traverse certain control children such as a templated control. If the control you are after lives in a template, it won’t be found.

So we added the following extension methods to deal with this. If you are not using 3.5 or want to avoid the extension methods, you could make a general purpose library out of these.

You can now get the control you are after by coding:

var button = Page.GetControl('MyButton') as Button; 

The extension methods do the recursive work for you. Hope this helps!

public static IEnumerable<Control> Flatten(this ControlCollection controls) {     List<Control> list = new List<Control>();     controls.Traverse(c => list.Add(c));     return list; }  public static IEnumerable<Control> Flatten(this ControlCollection controls,          Func<Control, bool> predicate) {     List<Control> list = new List<Control>();     controls.Traverse(c => { if (predicate(c)) list.Add(c); });     return list; }  public static void Traverse(this ControlCollection controls, Action<Control> action) {     foreach (Control control in controls)     {         action(control);         if (control.HasControls())         {             control.Controls.Traverse(action);         }     } }  public static Control GetControl(this Control control, string id) {     return control.Controls.Flatten(c => c.ID == id).SingleOrDefault(); }  public static IEnumerable<Control> GetControls(this Control control) {     return control.Controls.Flatten(); }