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TextElement.FontSize Property

Gets or sets the font size for the content of the element. This is a dependency property.

Namespace:  System.Windows.Documents
Assembly:  PresentationFramework (in PresentationFramework.dll)

public double FontSize { get; set; }
<object FontSize="double"/>
- or -
<object FontSize="qualifiedDouble"/>

XAML Values



String representation of a Double value equal to or greater than 0.0 but smaller than PositiveInfinity. An unqualified value is measured in device independent pixels. Strings need not explicitly include decimal points.


A double value as described above, followed by one of the following unit specifiers: px, in, cm, pt.

px (default) is device-independent units (1/96th inch per unit)

in is inches; 1in==96px

cm is centimeters; 1cm==(96/2.54) px

pt is points; 1pt==(96/72) px

Property Value

Type: System.Double
The desired font size to use in device independent pixels, greater than 0.001 and less than or equal to 35791. The default depends on current system settings and depends on the SystemFonts.MessageFontSize value.


FontSize is set to a value greater than 35791 or less than or equal to 0.001.

This dependency property also has an attached property usage. In XAML, the usage is <object TextElement.FontSize="value".../>, where object is an object element (typically a flow element) contained within a TextElement, and value is one of the string-format values as explained in XAML Values. In code, the attached property usage is supported by the GetFontSize and SetFontSize methods. The attached property usage is not common, because most elements that can be contained in a TextElement support an analogous nonattached FontSize property, which the content host uses for rendering.

The following example shows how to set the FontSize attribute, using Paragraph as the example element.

  FontFamily="Century Gothic, Courier New"  
    This text will use the Century Gothic font (if available), with fallback to Courier New.  It 
    will render with a font size of 16 points in ultra-expanded demi-bold italic.

The following figure shows how the preceding example renders.

Screenshot: Text with text properties set

The following example shows how to set the FontSize property programmatically.

Run run = new Run(
    "This text will use the Century Gothic font (if available), with fallback to Courier New."
    + "It will render with a font size of 16 pixels in ultra-expanded demi-bold italic.");
Paragraph par = new Paragraph(run);

par.FontFamily = new FontFamily("Century Gothic, Courier New");
par.FontSize = 16;
par.FontStretch = FontStretches.UltraExpanded;
par.FontStyle = FontStyles.Italic;
par.FontWeight = FontWeights.DemiBold;

Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0