How can I add a resource to a silverlight custom control? - silverlight

Question

I am trying to trim the selected value of a silverlight custom control combobox. I have found that using the IValueConverter class should be the way to go. So I create this in my library
public class StringTrimmer : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
return value.ToString().Trim();
}
public object ConvertBack(object value, Type targetType, object parameter,
System.Globalization.CultureInfo culture)
{
throw new NotImplementedException();
}
}
this is the xaml for the combobox
<UserControl x:Class="SilverlightControlLibrary.SilverlightComboBoxControl"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d" Height="25" Width="122">
<ComboBox Height="23" HorizontalAlignment="Left" VerticalAlignment="Top" Width="120"
Margin="0,0,0,0" Name="ModuleIDFilterCB"
ItemsSource="{Binding Path=Screen.LicenseModuleIDs, Mode=TwoWay}"
DisplayMemberPath="LicenseModuleName"
SelectedItem="{Binding Screen.bufferProp, Converter={StaticResource StringTrimmer},Mode=TwoWay}"
/>
</UserControl>
Except that the resource "StringTrimmer" for the SelectedItem can't be resolved. I tried adding this reference to the xaml and it still didnt work.
xmlns:c="clr-namespace:SilverlightControlLibrary"
EDIT: I also tried this
xmlns:custom="clr-namespace:SilverlightControlLibrary"
along with
SelectedItem="{Binding Screen.bufferProp, Converter= {StaticResource custom:StringTrimmer}, Mode=TwoWay}"
to no avail..
This http://msdn.microsoft.com/en-us/library/cc189061%28v=vs.95%29.aspx is what microsof has to say about XAML namespaces
and this http://msdn.microsoft.com/en-us/library/system.windows.data.ivalueconverter.convert.aspx is for the IValueConverter
Where am I going wrong?

Answer 1

You have to add static resource (UserControl.Resources section) to reference your converter e.g.:
<UserControl
x:Class="SilverlightControlLibrary.SilverlightComboBoxControl"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
Height="25"
Width="122"
xmlns:custom="clr-namespace:SilverlightControlLibrary">
<UserControl.Resources>
<custom:StringTrimmer x:Key="StringTrimmer" />
</UserControl.Resources>
<ComboBox Height="23"
HorizontalAlignment="Left"
VerticalAlignment="Top"
Width="120"
Margin="0,0,0,0"
Name="ModuleIDFilterCB"
ItemsSource="{Binding Path=Screen.LicenseModuleIDs, Mode=TwoWay}"
DisplayMemberPath="LicenseModuleName"
SelectedItem="{Binding Screen.bufferProp, Converter={StaticResource StringTrimmer}, Mode=TwoWay}" />
</UserControl>
For XAML reference you can use any name in x:Key attribute, not only "StringTrimmer".