CODEWITHSUNDEEP
c#wpftextbox
user1151923
user1151923

Reputation: 1872

force TextBox to refresh

I have a normal wpf TextBox control bound to a string property. I need the displayed text to be updated immediately after the binding or the .Text property is updated. I have tried 

((TextBox)sender).GetBindingExpression(TextBox.TextProperty).UpdateSource();
((TextBox)sender).GetBindingExpression(TextBox.TextProperty).UpdateTarget();

in the TextChanged event handler.

I've tried UpdateSourceTrigger=Explicit on the binding. I've tried

Application.Current.Dispatcher.BeginInvoke(
    DispatcherPriority.Input,
     new Action(() =>
     {
         statusTextBox.Text = "newValue";
     }));

and many different combinations of these. But the text displayed changes only once the method I update the textbox from exits.

XAML:

<TextBox x:Name="txBox" Height="150" Margin="0,0,0,0" VerticalAlignment="Top" TextWrapping="Wrap" VerticalScrollBarVisibility="Auto" AcceptsReturn="True"  VerticalContentAlignment="Top" Text="{Binding TextProperty}"Width="200" />

Upvotes: 5

Views: 25128

Answers (3)

Croko
Croko

Reputation: 97

Try the following code sequence, it worked for me-

Textblock1.Text = "ABC";
System.Windows.Forms.Application.DoEvents();
MainWindow.InvalidateVisual();
System.Threading.Thread.Sleep(40);

Upvotes: -1

recurzive
recurzive

Reputation: 9

You need to use TwoWay binding instead of changing the TextBox's value expicitly and you need to implement the INotifyPropertyChanged on the binded data's class.

Upvotes: 0

denis morozov
denis morozov

Reputation: 6316

your method if it's doing alot of work is probably holding the UI thread () the order of execution). Whatever you are doing in that method - do it in the background thread.

private void SomeMethod()
{
   Task.Factory.StartNew(() =>
        {
                       /// do all your logic here

                       //Update Text on the UI thread 
                       Application.Current.Dispatcher.BeginInvoke( DispatcherPriority.Input,
                      new Action(() => { statusTextBox.Text = "newValue";}));

                       //continue with the rest of the logic that take a long time
                    });

Just make sure that if in that method you are touching any UI elements, you do it on the UI thread, otherwise you will get a crash. Another, possibly better way to let UI thread know is to RaisePropertyChanged that you want the binding to know about, instead of directly manipulating the UI element.

Upvotes: 6

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