Clear Textbox Controls on Window

Question

I need to somehow loop through all controls on a UWP project's MainWindow. My first thought was that it would be a simple foreach on my window.Controls, but this doesn't exist in UWP.

I've browsed around and found a similar question here but this code didn't seem to work either when I tried it out. It looped successfully through the entire Window, only to find out that the objects found were none at all even though I could clearly see it going through the Grid and such.

Is there a way to do this in UWP using C#? I've tried to look for a VisualTreeHelper to do it, but no success on that either. Any help appreciated!

How do you create the Textboxes? Are they named? Do you have a ViewModel? By "clear" you mean "Clear the Text in the TextBoxes", not "Clear the window of TextBoxes"(remove them), right? How do you access them, and why don't you use the same mechanism to set the Text? — Manfred Radlwimmer, Nov 18 '16 at 10:29
I have the Textboxes declared in the xaml of my project. I named each and every single one of them and the intention is to clear out the text property. The problem is that I haven't accessed them before from the code behind, seeing as how all the textboxes get their content from a xmlDeserializer. — K.Warrens, Nov 18 '16 at 11:27

score 2 · Accepted Answer · answered Nov 18 '16 at 10:43

You can use the following method from the MSDN documentation to get all your textboxes from the page:

internal static void FindChildren<T>(List<T> results, DependencyObject startNode)
  where T : DependencyObject
{
    int count = VisualTreeHelper.GetChildrenCount(startNode);
    for (int i = 0; i < count; i++)
    {
        DependencyObject current = VisualTreeHelper.GetChild(startNode, i);
        if ((current.GetType()).Equals(typeof(T)) || (current.GetType().GetTypeInfo().IsSubclassOf(typeof(T))))
        {
            T asType = (T)current;
            results.Add(asType);
        }
        FindChildren<T>(results, current);
    }
}

It basically recursively get the children for the current item and add any item matching the requested type to the provided list.

Then, you just have to do the following somewhere in you page/button handler/...:

var allTextBoxes    = new List<TextBox>();
FindChildren(allTextBoxes, this);

foreach(var t in allTextBoxes)
{
    t.Text = "Updated!";
}

That worked perfectly! I had forgotten that the VisualTreeHelper StartNode would be of the DependencyObject type. Thank a ton! — K.Warrens, Nov 18 '16 at 11:31

score 0 · Answer 2 · answered Nov 18 '16 at 10:31

0

Simple way is just TextBox.Text = String.Empty; for every TextBox in View.

answered Nov 18 '16 at 10:31

Kuba

226
1
9

score 0 · Answer 3 · answered Dec 12 '16 at 12:05

You can use below code to find control.

 public static T FindChild<T>(DependencyObject depObj, string childName)
       where T : DependencyObject
    {
        // Confirm parent and childName are valid. 
        if (depObj == null) return null;

        // success case
        if (depObj is T && ((FrameworkElement)depObj).Name == childName)
            return depObj as T;

        for (int i = 0; i < VisualTreeHelper.GetChildrenCount(depObj); i++)
        {
            DependencyObject child = VisualTreeHelper.GetChild(depObj, i);

            //DFS
            T obj = FindChild<T>(child, childName);

            if (obj != null)
                return obj;
        }

        return null;
    }

and can clear text box.

  TextBox txtBox1= FindChild<TextBox>(this, "txtBox1");
        if (txtBox1!= null)
            txtBox1.Text= String.Empty;

Clear Textbox Controls on Window

3 Answers3