TextBlock.FontWeight Property

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

Gets or sets the top-level font weight for the TextBlock.

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


Public Property FontWeight As FontWeight
public FontWeight FontWeight { get; set; }
<TextBlock FontWeight="fontWeightsValue"/>

XAML Values

  • fontWeightsValue
    A FontWeights property name, such as Light, Normal, or UltraBold.

Property Value

Type: System.Windows.FontWeight
The requested font weight, which is a FontWeight that is obtained from one of the FontWeights property values. The default is Normal.


Dependency property identifier field: FontWeightProperty

This property can select only from fonts that exist in a font family. It does not programmatically create alternative weights, with one exception: if a font family contains a regular weight and no bold weight, and you specify a bold weight. In this case, Silverlight will simulate a bold weight by increasing the width of strokes by using a 2D graphic algorithm. Font fallback behavior does not change the property value, the property will remain as the value you set it to despite whatever visual behavior results due to font fallback.

The FontWeights values correspond to the usWeightClass definition in the OpenType specification. The usWeightClass represents an integer value between 1 and 999. Lower values indicate lighter weights, and higher values indicate heavier weights.

FontWeight settings for Run child elements override the settings on the containing TextBlock.

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.