Binding.Source Property

Microsoft Silverlight will reach end of support after October 2021. Learn more.

Gets or sets the data source for the binding.

Namespace:  System.Windows.Data
Assembly:  System.Windows (in System.Windows.dll)


Public Property Source As Object
public Object Source { get; set; }
<Binding Source="sourceReference"/>

XAML Values

  • sourceReference
    A reference to an existing object that serves as the data source. Typically the object is created in a ResourceDictionary and given a key, then referenced by using the StaticResource markup extension. For instance: <Binding Source="{StaticResource customDataSourceObject}" .../>

Property Value

Type: System.Object
The source object that contains the data for the binding.


Exception Condition

The Binding has already been attached to a target element, and cannot be modified.


The ElementName or RelativeSource property has already been set.


The Source property is optional on a Binding object. If the Source property is set on a Binding object, the data source applies only to the target properties that use that Binding object.

To create a data source that is inherited by all the child elements in the tree, instead set the DataContext property on the parent element. Then the parent element and all its children look to the DataContext as the source of their bindings. If the Source is set for a child element, it will override the DataContext inheritance in that instance.

The target can bind directly to the Source object if the path is empty or to a property of the Source object as defined by the path. The path is set either in XAML with the binding syntax or when the Binding object is created.

XAML Usage Notes

See Binding Markup Extension to learn how Source can be set as a binding property through the Binding markup extension, which enables specifying an entire Binding as an attribute string.

Property element syntax to create an object element that fills a Binding.Source property element is possible, but uncommon.

Source, RelativeSource, and ElementName are mutually exclusive in a binding. If you have set one of these attributes, then setting either of the other two in a binding (through XAML or through code) will cause an exception.


'Create the source string 
Dim s As String = "Hello"

'Create the binding description 
Dim b As New Binding("")
b.Mode = BindingMode.OneTime
b.Source = s

'Attach the binding to the target 
MyText.SetBinding(TextBlock.TextProperty, b)
//Create the source string
string s = "Hello";

//Create the binding description
Binding b = new Binding("");
b.Mode = BindingMode.OneTime;
b.Source = s;

//Attach the binding to the target
MyText.SetBinding(TextBlock.TextProperty, b);

Version Information


Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0


For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.