Bind to methods with ObjectDataProvider

Bind to methods with ObjectDataProvider

Two classes inherit from DataSourceProvider. XmlDataProvider and ObjectDataProvider. ObjectDataProvider wraps an object and allows you to bind to the wrapped object in XAML. The ObjectDataProvider has a ConstructorParameters-Property for creating an object by using a constructor with parameters.

The cool thing is that a Data Binding to the wrapped object of the ObjectDataProvider is not all. With ObjectDataProvider you can even bind to a static method or to an instance method of the wrapped object. I’ll show you an example.

Just think about a really simple ComboBox that allows the user to chose some colors. Between the name of the color a rectangle filled with the color should be displayed (In WPF this is quite easy. You haven’t to create eventhandlers like you would do in Windows Forms. There you consumed the DrawItem-event of the ComboBox and used the Graphics-object to do a little bit of GDI+. In WPF GDI+ is gone). WPF’s Color class doesn’t have a name property. So just create a static class ColorHelper with one static method GetColorNames that returns an IEnumerable<string> and uses reflection to iterate over all public static properties of the Colors class that all contain Color-objects.

The Window in the following XAML contains an ObjectDataProvider that uses the Static GetColorNames-Method of the ColorHelper class. The ItemsSource-Property (Typ: IEnumerable) of the ComboBox is bound to the ObjectDataProvider. The ItemTemplate-Property contains a DataTemplate that specifies the Visual Tree (the "look") of an item. Thanks to TypeConverters, a SolidColorBrush-Object is created for the Fill-Property of each Rectangle specified in the DataTemplate.

The displayed, open ComboBox looks like this:

comboBoxObjectDataProvider

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Comments (7)

  • Ravendarque

    Great article Thomas. One small thing: it may not work ‘as is’ because the following line:

    …xmlns:local=”clr-namespace:SimpleObjectDataProvider”>

    refers to the namespace ‘SimpleObjectDataProvider’ in your project. It needs to be changed to the namespace used in the readers’ own projects.

    April 3, 2008 at 3:43 pm
  • hubethom

    Hi Ravendarque.

    Thanks for the hint. Yes, of course, the namespace in the XAML-File must be changed to the one used in your project.

    Thomas

    April 4, 2008 at 12:14 pm
  • Slobodan

    You rock man :)
    tnx for great code

    February 3, 2009 at 2:22 pm
  • Mario

    wow, thanks for this code,
    have u any idea how can i set the parameter directly in the binding

    this worky correctly ObjectDataProvider.MethodParameters

    but i need example like this:
    Text=”{Binding Source={StaticResource TranslateCustomer, Parameter=string1, Parameter=string2}}”

    July 30, 2009 at 4:48 pm
  • nadun

    hi,

    thanks for the code. helped me to know how to set the itemssource to an objectdataprovider :)

    July 21, 2010 at 4:19 pm
  • Bergfall

    Learning WPF has been surprisingly tricky, due to the many different new “aspects” of it in comparison to ASP.NET or WinForms.

    You just taught me ObjectDataSource, one down, dozens to go;
    Thanks!

    October 15, 2011 at 4:11 pm
  • Luis Perez

    Great article Thomas. I actually found myself wanting to bind to methods a lot myself. In my case I ended up creating something that let me do this: {BindTo SaveObject()}. You can find it here: http://www.simplygoodcode.com/2012/08/simpler-wpf-binding.html

    Thanks and happy blogging.

    September 28, 2013 at 1:22 am

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