Problem binding data to controls in dynamically created wpf TabItem

0
votes

I am having problem putting data into controls on wpf TabItem. I have defined several DataTemplates in xaml. Here is one of them:

<Window.Resources>
...
<DataTemplate x:Key="memoTab">
<TextBox Name="memoTextBox" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" AcceptsReturn="True" />
</DataTemplate>
...
</Window.Resources>

I then create new tab in code behind as follows:

TabItem tab = new TabItem();
tab.Header = "Memo";
tab.ContentTemplate = (DataTemplate)FindResource("memoTab");
tab.ApplyTemplate();
System.Windows.Controls.TextBox tb = (System.Windows.Controls.TextBox)tab.Template.FindName("memoTextBox", tab);
if (tb != null) tb.DataContext = memo; //string memo is created earlier as linq query
tabControl.Items.Add(tab); //tabControl is xaml defined

The problem is that tb is always null, and therefore no data appears in the text box (the text box itself shows up in the tab and it is functional)

I do not use xaml to create tabs in tabControl (except the first one, which is not using DataTemplate and is fine) because they are meant to be added and removed by the user at run time.

Any ideas?

1
wpftabitemdatatemplate

1 Answers

0
votes

You may need to get the ContentPresenter of the TabItem. You can reference the MSDN for this.

// Getting the ContentPresenter of tab
ContentPresenter myContentPresenter = FindVisualChild<ContentPresenter>(tab);

// Finding textBox from the DataTemplate that is set on that ContentPresenter
DataTemplate myDataTemplate = myContentPresenter.ContentTemplate;
TextBox myTextBox = (TextBox)myDataTemplate.FindName("memoTextbox", myContentPresenter);

The method FindVisualChild...

private childItem FindVisualChild<childItem>(DependencyObject obj)
    where childItem : DependencyObject
{
    for (int i = 0; i < VisualTreeHelper.GetChildrenCount(obj); i++)
    {
        DependencyObject child = VisualTreeHelper.GetChild(obj, i);
        if (child != null && child is childItem)
            return (childItem)child;
        else
        {
            childItem childOfChild = FindVisualChild<childItem>(child);
            if (childOfChild != null)
                return childOfChild;
        }
    }
    return null;
}