I have a WPF application (.Net 4.5.1) where I create the items in a combo box dynamically, I bind to the ItemSource with an observable collection. But when I do this i get two binding errors, one for VeticalContentAlignment and one for HorizontalContentAlignment, for each item that I add.
System.Windows.Data Error: 4 :
Cannot find source for binding with reference 'RelativeSource FindAncestor, AncestorType='System.Windows.Controls.ItemsControl', AncestorLevel='1''.
BindingExpression:Path=VerticalContentAlignment; DataItem=null; target element is 'ComboBoxItem' (Name='PhoneItem');
target property is 'VerticalContentAlignment' (type 'VerticalAlignment')
I have googled and found some pointers that did not help , eg adding a global style
<Style TargetType="{x:Type ComboBoxItem}">
<Setter Property="HorizontalContentAlignment" Value="Stretch" />
<Setter Property="VerticalContentAlignment" Value="Center" />
</Style>
or defining an inline container style in the combo box.
<ComboBox.ItemContainerStyle>
<Style TargetType="ComboBoxItem">
<Setter Property="HorizontalContentAlignment" Value="Left" />
<Setter Property="VerticalContentAlignment" Value="Center" />
</Style>
</ComboBox.ItemContainerStyle>
I can reproduce this in a clean project where I have no styling and only a combo box bound to an observable collection if anyone is interested in having a look at my stripped code.
Update 1 - My XAML and code behind
<Window x:Class="WpfApplicationDynamicComboBox.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525">
<Grid>
<StackPanel>
<Button Click="ButtonBase_OnClick" Margin="5">Load Combobox</Button>
<ComboBox Name="DynamicComboBox"
ItemsSource="{Binding MyItems}"
Width="400"/>
</StackPanel>
</Grid>
</Window>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
DataContext = this;
MyItems = new ObservableCollection<ComboBoxItem>();
MyItems.Add( new ComboBoxItem {Content = string.Format( "Phone: {0}", "123" ), Name = "PhoneItem_" + DateTime.Now.Second} );
}
public ObservableCollection<ComboBoxItem> MyItems { get; set; }
private void ButtonBase_OnClick( object sender, RoutedEventArgs e )
{
MyItems.Add( new ComboBoxItem {Content = string.Format( "Phone: {0}", "123" ), Name = "PhoneItem_" + DateTime.Now.Second} );
}
}
Update 2 - Link to sample project http://bit.ly/1fwvgkZ
Any help getting rid of these errors are greatly appreciated!
Okay fixed your error. Just replace your code behind with
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
DataContext = this;
MyItems = new ObservableCollection<ComboBoxItem>();
MyItems.Add(new ComboBoxItem
{
Name = "PhoneItem_" + DateTime.Now.Second,
Content = string.Format("Phone: {0}", "123"),
HorizontalContentAlignment = HorizontalAlignment.Left,
VerticalContentAlignment = VerticalAlignment.Center
});
}
public ObservableCollection<ComboBoxItem> MyItems { get; set; }
private void ButtonBase_OnClick(object sender, RoutedEventArgs e)
{
MyItems.Add(new ComboBoxItem
{
Name = "PhoneItem_" + DateTime.Now.Second,
Content = string.Format("Phone: {0}", "123"),
HorizontalContentAlignment = HorizontalAlignment.Left,
VerticalContentAlignment = VerticalAlignment.Center
});
}
}
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