Looping Through Controls in ASP.NET

In my recent development I have badly needed to read all the controls from asp.net page. After searching I have found lots of solution. Now I want share with you one of these solution. In this solution we read all the control from asp.net page with out using master page.

**Remember to add namespace  System.Collections.Generic
Code: C#

private static Control FindControlIterative 
(Control root, string id)
            Control ctl = root;
            LinkedList ctls = new LinkedList();

            while (ctl != null)
                if (ctl.ID == id)
                    return ctl;
                foreach (Control child in ctl.Controls)
                    if (child.ID == id)
                        return child;
                    if (child.HasControls())
                ctl = ctls.First.Value;
            return null;

 Code: VB.net
Private Shared Function FindControlIterative
(ByVal root As Control, _
ByVal id As String) As Control

  Dim ctl As Control = root
  Dim ctls As LinkedList(Of Control) = 
                  New LinkedList(Of Control)

  Do While (ctl IsNot Nothing)
   If ctl.ID = id Then
    Return ctl
   End If
   For Each child As Control In ctl.Controls
    If child.ID = id Then
     Return child
    End If
    If child.HasControls() Then
    End If
   ctl = ctls.First.Value

  Return Nothing

 End Function

 Read Control when use Master Page:

And this is where things get a bit tricky with MasterPages. The problem is that when you use MasterPages the page hierarchy drastically changes. Where a simple this.FindControl() used to give you a control instance you now have to drill into the container hierarchy pretty deeply just to get to the content container.


public static Control FindControlRecursive(Control Root, string Id)
if (Root.ID == Id)
return Root;

foreach (Control Ctl in Root.Controls)
Control FoundCtl = FindControlRecursive(Ctl, Id);
if (FoundCtl != null)
return FoundCtl;
return null;

You can use this method this way..

this.lblError = FindControlRecursive(this.Master,"lblError") as Label;


dotNetFollower said…
Nice post! My own FindControlRecursive helped me out many times. Especially, when I deal with MasterPages. For example, one of such usage is shown in my post here – http://dotnetfollower.com/wordpress/2010/12/sharepoint-add-onchange-attribute-to-dropdownchoicefield/.
Thank you!
Anonymous said…
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