Filter enum values in ObjectDataProvider ?

Question

Hello,

Using a ObjectDataProvider like this, http://blog.davidsandor.com/post/WPF-How-to-bind-to-an-enum-in-XAML.aspx, is there a way to filter the enum values so that only a subset of the enumeration, specifically all but the first and last value, are returned?

Thanks,

Per

Answer 1

Hi Per,

You can generate any object data you want by implementing the methed you call in the ObjectDataProvider. The ObjectDatProvider will take any return value of that method as the datasource.

Here is a simple sample code which did what you want. Hope it helps.

MainWindow.xaml

<Window x:Class="BindingTOEnum.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:system="clr-namespace:System;assembly=mscorlib"
    xmlns:local="clr-namespace:BindingTOEnum"
    Title="MainWindow" Height="350" Width="525">
  <Window.Resources>
    <ObjectDataProvider x:Key="MidValues" ObjectType="{x:Type local:EnumDataProvider}" MethodName="GetMidValues">
      <ObjectDataProvider.MethodParameters>
        <x:Type TypeName="HorizontalAlignment"/>
      </ObjectDataProvider.MethodParameters>
    </ObjectDataProvider>
    <ObjectDataProvider x:Key="AllValues" ObjectType="{x:Type system:Enum}" MethodName="GetValues">
      <ObjectDataProvider.MethodParameters>
        <x:Type TypeName="HorizontalAlignment"/>
      </ObjectDataProvider.MethodParameters>
    </ObjectDataProvider>
  </Window.Resources>
  <Grid>
    <StackPanel>
      <TextBlock>AllValues:</TextBlock>
      <ListBox ItemsSource="{Binding Source={StaticResource AllValues}}"/>
      <TextBlock>MidValues:</TextBlock>
      <ListBox ItemsSource="{Binding Source={StaticResource MidValues}}"/>
    </StackPanel>
  </Grid>
</Window>

C#

public class EnumDataProvider
  {
    public Array GetMidValues(Type enumType)
    {
      Array allValues = Enum.GetValues(enumType);
      int arrayLength = allValues.Length - 2;
      if (arrayLength < 0)
      {
        arrayLength = 0;
      }

      Object[] midValues = new Object[arrayLength];
      for (int i = 0; i < arrayLength; i++)
      {
        midValues[i] = allValues.GetValue(i + 1);
      }
      return midValues;
    }
  }

If you still have any doubts or concerns about this issue, please feel free to let me know.

Best regards,

Min

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Answer 2

Thanks, this is very similar to the solution came up with myself after a good nights sleep ;P Late-night programming doesn't pay off :)