Enable/Disable controls on ComboBox selection in Xaml - wpf

Question

How to enable /disable controls like textbox,label,textblock if combobox is selected/not-selected? e.g. If selected index is greater than zero, enable controls else disable.How to bind IsEnabled properties of the control with combobox selection?

Answer 1

You can bind IsEnabled to the SelectedIndex property of the ComboBox and use a IValueConverter to convert it to Boolean. For instance, in your XAML (showing enabling a Button):
<ComboBox x:Name="cmbBox" ItemsSource="{Binding Source={StaticResource DataList}}"/>
<Button Grid.Column="1" IsEnabled="{Binding ElementName=cmbBox, Path=SelectedIndex, Converter={StaticResource IndexToBoolConverter}}"/>
Then you need a converter as well, such as:
public class IndexToBoolConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
if ((int)value > 0)
{
return true;
}
else
{
return false;
}
}
public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
throw new NotImplementedException();
}
}
You'll also have declare the Converter as a resource, such as in your Window.
<local:IndexToBoolConverter x:Key="IndexToBoolConverter"/>

Answer 2

I would probably just do something like this.
<Grid>
<Grid.Resources>
<Style TargetType="{x:Type Button}">
<Style.Triggers>
<DataTrigger Binding="{Binding Path=SelectedItem,
ElementName=TheCombo}"
Value="{x:Null}">
<Setter Property="IsEnabled" Value="False" />
</DataTrigger>
</Style.Triggers>
</Style>
</Grid.Resources>
<StackPanel HorizontalAlignment="Center" VerticalAlignment="Center">
<ComboBox x:Name="TheCombo" Width="100">
<ComboBoxItem>Blah</ComboBoxItem>
<ComboBoxItem>Blah</ComboBoxItem>
<ComboBoxItem>Blah</ComboBoxItem>
</ComboBox>
<Button Content="Click Me" Margin="0,10"/>
</StackPanel>
</Grid>
Hope this helps, cheers!

Answer 3

Try with this
Dispatcher.BeginInvoke(new Action(() =>
{
ToggleButton dropDownButton = GetFirstChildOfType<ToggleButton>(cboMedicos);
if (dropDownButton != null)
{
dropDownButton.IsEnabled = false;
}
}), System.Windows.Threading.DispatcherPriority.Render);
public static T GetFirstChildOfType<T>(DependencyObject dependencyObject) where T : DependencyObject
{
if (dependencyObject == null)
{
return null;
}
for (var i = 0; i < VisualTreeHelper.GetChildrenCount(dependencyObject); i++)
{
var child = VisualTreeHelper.GetChild(dependencyObject, i);
var result = (child as T) ?? GetFirstChildOfType<T>(child);
if (result != null)
{
return result;
}
}
return null;
}