WPF: How do I loop through the all controls in a window?

Question

How do I loop through the all controls in a window in WPF?

Answer 1

I've used the following to get all controls.

    public static IList<Control> GetControls(this DependencyObject parent)
    {            
        var result = new List<Control>();
        for (int x = 0; x < VisualTreeHelper.GetChildrenCount(parent); x++)
        {
            DependencyObject child = VisualTreeHelper.GetChild(parent, x);
            var instance = child as Control;

            if (null != instance)
                result.Add(instance);

            result.AddRange(child.GetControls());
        } 
        return result;
    }

Answer 2

Class to get a list of all the children's components of a control:

class Utility
    {
        private static StringBuilder sbListControls;

        public static StringBuilder GetVisualTreeInfo(Visual element)
        {
            if (element == null)
            {
                throw new ArgumentNullException(String.Format("Element {0} is null !", element.ToString()));
            }

            sbListControls = new StringBuilder();

            GetControlsList(element, 0);

            return sbListControls;
        }

        private static void GetControlsList(Visual control, int level)
        {
            const int indent = 4;
            int ChildNumber = VisualTreeHelper.GetChildrenCount(control);

            for (int i = 0; i <= ChildNumber - 1; i++)
            {
                Visual v = (Visual)VisualTreeHelper.GetChild(control, i);

                sbListControls.Append(new string(' ', level * indent));
                sbListControls.Append(v.GetType());
                sbListControls.Append(Environment.NewLine);

                if (VisualTreeHelper.GetChildrenCount(v) > 0)
                {
                    GetControlsList(v, level + 1);
                }
            }
        }
    } 

Answer 3

I found this in the MSDN documenation so it helps.

// Enumerate all the descendants of the visual object.
static public void EnumVisual(Visual myVisual)
{
    for (int i = 0; i < VisualTreeHelper.GetChildrenCount(myVisual); i++)
    {
        // Retrieve child visual at specified index value.
        Visual childVisual = (Visual)VisualTreeHelper.GetChild(myVisual, i);

        // Do processing of the child visual object.

        // Enumerate children of the child visual object.
        EnumVisual(childVisual);
    }
}

Looks simpler to me. I used it to find textboxes in a form and clear their data.

Answer 4

A slight variation on the MSDN answer ... just pass in an empty List of Visual objects into it and your collection will be populated with all the child visuals:

/// <summary>
/// Enumerate all the descendants (children) of a visual object.
/// </summary>
/// <param name="parent">Starting visual (parent).</param>
/// <param name="collection">Collection, into which is placed all of the descendant visuals.</param>
public static void EnumVisual(Visual parent, List<Visual> collection)
{
    for (int i = 0; i < VisualTreeHelper.GetChildrenCount(parent); i++)
    {
        // Get the child visual at specified index value.
        Visual childVisual = (Visual)VisualTreeHelper.GetChild(parent, i);

        // Add the child visual object to the collection.
        collection.Add(childVisual);

        // Recursively enumerate children of the child visual object.
        EnumVisual(childVisual, collection);
    }
}

Answer 5

This way is superior to the MSDN method, in that it's reusable, and it allows early aborting of the loop (i.e. via, break;, etc.) -- it optimizes the for loop in that it saves a method call for each iteration -- and it also lets you use regular for loops to loop through a Visual's children, or even recurse it's children and it's grand children -- so it's much simpler to consume.

To consume it, you can just write a regular foreach loop (or even use LINQ):

foreach (var ctrl in myWindow.GetChildren())
{
    // Process children here!
}

Or if you don't want to recurse:

foreach (var ctrl in myWindow.GetChildren(false))
{
    // Process children here!
}

To make it work, you just need put this extension method into any static class, and then you'll be able to write code like the above anytime you like:

public static IEnumerable<Visual> GetChildren(this Visual parent, bool recurse = true)
{
    if (parent != null)
    {
        int count = VisualTreeHelper.GetChildrenCount(parent);
        for (int i = 0; i < count; i++)
        {
            // Retrieve child visual at specified index value.
            var child = VisualTreeHelper.GetChild(parent, i) as Visual;

            if (child != null)
            {
                yield return child;

                if (recurse)
                {
                    foreach (var grandChild in child.GetChildren(true))
                    {
                        yield return grandChild;
                    }
                }
            }
        }
    }
}

Also, if you don't like recursion being on by default, you can change the extension method's declaration to have recurse = false be the default behavior.