FontSize Property

Control.FontSize Property


Gets or sets the font size.

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

public double FontSize { get; set; }

Property Value

Type: System.Double

The size of the text in the Control. The default is SystemFonts.MessageFontSize. The font size must be a positive number.

This property only affects a control whose template uses the FontSize property as a parameter. On other controls, this property has no impact.

<object FontSize="double"/>
- or –
<object FontSize ="qualifiedDouble"/>



A string representation of a Double value. This is interpreted as a device-independent unit (1/96th inch) measurement. Strings need not explicitly include decimal points. For example, a value of 1 is acceptable.

The same Double range restrictions that are mentioned in the Property Value section apply here.


A double value as previously described that is followed by one of these unit declaration strings: 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

Note   In many cases a double may be set to "Auto," but a Control.FontSize does not render if set to "Auto".

The following example shows how to set the font size property of a control.

<Button Name="btn3" FontSize="10.0" 
void ChangeFontSize(object sender, RoutedEventArgs e)
    fsize = btn3.FontSize;
    if (fsize == 16.0)
        btn3.FontSize = 10.0;
        btn3.Content = "FontSize";
        btn3.FontSize = 16.0;
        btn3.Content = "Control font size changes from 10 to 16.";

.NET Framework
Available since 3.0
Available since 2.0
Windows Phone Silverlight
Available since 7.0
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