How do I get the ToggleButton from ComboBox Control

Question

I was checking control template of ComboBox(http://msdn.microsoft.com/en-us/library/ms752094(v=vs.110).aspx), where they have used Toggle Button to toggle the Popup. Is there a way I could get the toggle button from code behind?

I had tried this, but to no avail :-(

var uiElement = (ComboBox)sender;
var toggleButton = uiElement.FindResource(typeof(ToggleButton)) as ToggleButton;

This will help you: [WPF ways to find controls](http://stackoverflow.com/questions/636383/wpf-ways-to-find-controls) — Valera Scherbakov, Jan 22 '14 at 12:49
This can take a performance hit for me to traverse the Visual Tree, any other suggestions? — Arun Selva Kumar, Jan 22 '14 at 12:53
You have to traverse VisualTree to get child. And why this will be a performance hit? — Rohit Vats, Jan 22 '14 at 13:13

score 1 · Answer 1 · answered Jan 22 '14 at 13:35

If you now the name of the ToggleButton then you can use following code:

var uiElement = (ComboBox)sender;
var toggleButton = uiElement.Template.FindName("<Your ToggleButton Name Here>",uiElement) as ToggleButton;

if(toggleButton!=null)
{
     // Your code goes here.
}

If you don't know the name of the ToggleButton then in that case the only option is to travers through visual tree and find an element of type toggle button. Sample code below:

    internal static List<T> FindVisualChild<T>(this DependencyObject depObj) where T : DependencyObject
    {
        if (depObj != null)
        {
            List<T> childItems = null;
            for (int i = 0; i < VisualTreeHelper.GetChildrenCount(depObj); i++)
            {

                if (childItems == null)
                    childItems = new List<T>();

                DependencyObject child = VisualTreeHelper.GetChild(depObj, i);
                if (child != null && child is T)
                {
                    childItems.Add((T)child);
                }

                var recursiveChildItems = FindVisualChild<T>(child);
                if (recursiveChildItems != null && recursiveChildItems.Count > 0)
                    childItems.AddRange(recursiveChildItems);
            }
            return childItems;
        }
        return null;
    }

Above method is an extension to DependencyObject and will return all the elements of the specified type from the visual tree. If you want only first element of specified type then you can make slight changes in the method and can break the loop when you get the first element of the specified type and return it.

+1 for correct and expanded answer. You gave a correct answer, but topic starter not appreciate it (( — Valera Scherbakov, Jan 27 '14 at 22:36
I needed this as well, tried the FindVisualChild method on a combobox, but didn't return any togglebutton :( — WtFudgE, Dec 23 '14 at 12:41

score 0 · Accepted Answer · answered Jan 22 '14 at 17:14

0

This thing got me answer.

var uiElement = (ComboBox)sender;
var toggleButton = uiElement.FindName("ToggleButton") as ToggleButton;

answered Jan 22 '14 at 17:14

Arun Selva Kumar

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How do I get the ToggleButton from ComboBox Control

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