MVVM- How can I bind to a property, which is not a DependancyProperty?
- by highone
I have found this question http://stackoverflow.com/questions/2245928/mvvm-and-the-textboxs-selectedtext-property. However, I am having trouble getting the solution given to work. This is my non-working code:
View:
SelectedText and Text are just string properties from my ViewModel.
<TextBox Text="{Binding Path=Text, UpdateSourceTrigger=PropertyChanged}" Height="155" HorizontalAlignment="Left" Margin="68,31,0,0" Name="textBox1" VerticalAlignment="Top" Width="264" AcceptsReturn="True" AcceptsTab="True" local:TextBoxHelper.SelectedText="{Binding SelectedText, UpdateSourceTrigger=PropertyChanged}" />
<TextBox Text="{Binding SelectedText, Mode=OneWay, UpdateSourceTrigger=PropertyChanged}" Height="154" HorizontalAlignment="Left" Margin="82,287,0,0" Name="textBox2" VerticalAlignment="Top" Width="239" />
TextBoxHelper
public static class TextBoxHelper
{
#region "Selected Text"
public static string GetSelectedText(DependencyObject obj)
{
return (string)obj.GetValue(SelectedTextProperty);
}
public static void SetSelectedText(DependencyObject obj, string value)
{
obj.SetValue(SelectedTextProperty, value);
}
// Using a DependencyProperty as the backing store for SelectedText. This enables animation, styling, binding, etc...
public static readonly DependencyProperty SelectedTextProperty =
DependencyProperty.RegisterAttached(
"SelectedText",
typeof(string),
typeof(TextBoxHelper),
new FrameworkPropertyMetadata(null, FrameworkPropertyMetadataOptions.BindsTwoWayByDefault, SelectedTextChanged));
private static void SelectedTextChanged(DependencyObject obj, DependencyPropertyChangedEventArgs e)
{
TextBox tb = obj as TextBox;
if (tb != null)
{
if (e.OldValue == null && e.NewValue != null)
{
tb.SelectionChanged += tb_SelectionChanged;
}
else if (e.OldValue != null && e.NewValue == null)
{
tb.SelectionChanged -= tb_SelectionChanged;
}
string newValue = e.NewValue as string;
if (newValue != null && newValue != tb.SelectedText)
{
tb.SelectedText = newValue as string;
}
}
}
static void tb_SelectionChanged(object sender, RoutedEventArgs e)
{
TextBox tb = sender as TextBox;
if (tb != null)
{
SetSelectedText(tb, tb.SelectedText);
}
}
#endregion
}
What am I doing wrong?
