Finding control on SharePoint page - sharepoint

Question

Im trying to locate an SPDataSource control located on my SharePoint page. I found the following code which probably works fine, I just don't know what to pass into it.
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;
}
I don't know how to have it search the whole page or at the very least the ContentPlaceHolder that the control is in.
edit
Looks like I have a more rudimentary issue here. Not sure how to explain but I'm not opening up the page before running my code. I'm opening the site via the following:
using (SPWeb web = thisSite.Site.OpenWeb("/siteurl/,true))
So when I try to find the page below I'm getting Object reference not set to instance of object.
var page = HttpContext.Current.Handler as Page;
Perhaps I'm going about this the wrong way, I'm in my infancy here so I'm just kind of stumbling along figuring stuff out!

Answer 1

What you got is actually not SharePoint specific, it's c# asp.net.
Anyway, you could call it like this
var page = HttpContext.Current.Handler as Page;
var control = page; // or put the element you know exist that omit (is a parent) of the element you want to find
var myElement = FindControlRecursive(control, "yourelement");
Most likely you'll need to cast the return as well
var myElement = (TextBox)FindControlRecursive(control, "yourelement");
// or
var myElement = FindControlRecursive(control, "yourelement") as TextBox;
There are however more efficient ways to write such a method, here is one simple example
public static Control FindControlRecursive(string id)
{
var page = HttpContext.Current.Handler as Page;
return FindControlRecursive(page, id);
}
public static Control FindControlRecursive(Control root, string id)
{
return root.ID == id ? root : (from Control c in root.Controls select FindControlRecursive(c, id)).FirstOrDefault(t => t != null);
}
Call it the same way as I suggested earlier.
If you are handling larger pages the methods above might be a bit slow, what you should do is aim for a method using generics instead. They are way faster than traditional methods.
Try this one
public static T FindControlRecursive<T>(Control control, string controlID) where T : Control
{
// Find the control.
if (control != null)
{
Control foundControl = control.FindControl(controlID);
if (foundControl != null)
{
// Return the Control
return foundControl as T;
}
// Continue the search
foreach (Control c in control.Controls)
{
foundControl = FindControlRecursive<T>(c, controlID);
if (foundControl != null)
{
// Return the Control
return foundControl as T;
}
}
}
return null;
}
You call it like this
var mytextBox = FindControlRecursive<TextBox>(Page, "mytextBox");