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Jose
Jose

Reputation: 11091

WPF global font size

I'm creating a WPF app and I would like to know the best way to be able to change the font size for every element in the ui. Do I create a resource dictionary and set Styles to set the font size for all the controls I use?

What is the best practice?

Upvotes: 90

Views: 106447

Answers (11)

Mr. Squirrel.Downy
Mr. Squirrel.Downy

Reputation: 1167

Let's have some BLACK MAGIC things:

  1. Add a double resource into your Application resource
<Application.Resources>
    <sys:Double xmlns:sys="clr-namespace:System;assembly=mscorlib" x:Key="GlobalFontSize">12</sys:Double>
</Application.Resources>
  1. Add a static property in your App class
public static double GlobalFontSize
{
    get => (double)Current.Resources["GlobalFontSize"];
    set => Current.Resources["GlobalFontSize"] = value;
}
  1. Use this resource any where you want by DynamicResource
FontSize="{DynamicResource GlobalFontSize}"
  1. Access property App.GlobalFontSize in any way to change value, binding is okay!
App.GlobalFontSize = 20;
//Or
{Binding Path=(local:App.GlobalFontSize)}

Upvotes: 2

Muhammad Ali
Muhammad Ali

Reputation: 317

Using Resources in XAML is the way to go. Although there are many great answers to this question, I would like to add my two cents to the SCOPE of the Resource.

For Global accessibility in all of the Windows and User Controls of the Project, you can have your resource in the App.xaml file

<Application.Resources>
    <Style TargetType="{x:Type Control}" x:Key="GlobalFontSize">
        <Setter Property="FontSize" Value="28"/>
    </Style>
</Application.Resources>

For accessibility at a Window level, you can have your resource in your xaml file for Window

<Window.Resources>
    <Style TargetType="{x:Type Control}" x:Key="GlobalFontSize">
        <Setter Property="FontSize" Value="28"/>
    </Style>
</Window.Resources>

You could even have it at a Control level, for example

<DockPanel.Resources>
    <Style TargetType="{x:Type Control}" x:Key="GlobalFontSize">
        <Setter Property="FontSize" Value="28"/>
    </Style>
</DockPanel.Resources>

Upvotes: 2

Jim Balter
Jim Balter

Reputation: 16406

To dynamically change the font size globally with ctrl-mousewheel:

XAML:

<Window Name="MainWindow" ... PreviewMouseWheel="MainWindow_PreviewMouseWheel">

code behind:

private void MainWindow_PreviewMouseWheel(object sender, MouseWheelEventArgs e)
{
    if ((Keyboard.Modifiers & ModifierKeys.Control) != 0)
    {
        if (e.Delta > 0)
            ++mainCtrl.FontSize;
        if (e.Delta < 0 && mainCtrl.FontSize > 1)
             --mainCtrl.FontSize;
    }
}

Upvotes: 3

Janaka R Rajapaksha
Janaka R Rajapaksha

Reputation: 3744

<Window> has a property FontSize.

So you can set desired fontsize in element if you want to change the fontsize in all the elements within that window.

<Window FontSize="12">

</Window>

Upvotes: 51

Lin
Lin

Reputation: 1046

TextElement.FontSize is an inherit property, which means you can simply set the font size at root element, and all the children elements will use that size (as long as you don't change them manually)

Upvotes: 7

Vipul
Vipul

Reputation: 1583

Application.Current.MainWindow.FontSize = _appBodyFontSize;

This way you can change the Font Size at run time also.

Upvotes: 12

Neal
Neal

Reputation: 359

Another option is to define the FontFamily and FontSize as resources.

<FontFamily x:Key="BaseFontFamily">Calibri</FontFamily>
<sys:Double x:Key="BaseFontSize">12</sys:Double>

That way you can use them in your setters.

Upvotes: 35

Pablonete
Pablonete

Reputation: 1524

If you need to programmatically change global FontSize, not statically (XAML), to be applied once for all your windows, you can do:

TextElement.FontSizeProperty.OverrideMetadata(
            typeof(TextElement),
            new FrameworkPropertyMetadata(16.0));

        TextBlock.FontSizeProperty.OverrideMetadata(
            typeof(TextBlock),
            new FrameworkPropertyMetadata(16.0));

This values are applied to any TextBlock, Labels and almost any text in any windows, whereas it has not a explicit FontSize defined. But this does not affect for TextBox, you have to write a similar code for it or any other special controls.

Upvotes: 4

Matze
Matze

Reputation: 1584

FontSizeProperty is inherited from Parent Control. So you just need to change FontSize of your main window.

If you don't need dynamic behaviour this should work:

Add a style for Window to your ResourceDictionary

<Style TargetType="{x:Type Window}">
     <Setter Property="FontSize" Value="15" />
</Style>

Apply the style to your main form (will not be applied implicit because its a derived type)

 Style = (Style)FindResource(typeof (Window));

Upvotes: 53

Carlo
Carlo

Reputation: 25959

I'd do it this way:

<Window.Resources>
        <Style TargetType="{x:Type Control}" x:Key="baseStyle">
            <Setter Property="FontSize" Value="100" />
        </Style>
        <Style TargetType="{x:Type Button}" BasedOn="{StaticResource baseStyle}"></Style>
        <Style TargetType="{x:Type Label}" BasedOn="{StaticResource baseStyle}"></Style>
        <Style TargetType="{x:Type TextBox}" BasedOn="{StaticResource baseStyle}"></Style>
        <Style TargetType="{x:Type ListView}" BasedOn="{StaticResource baseStyle}"></Style>
        <!-- ComboBox, RadioButton, CheckBox, etc... -->
    </Window.Resources>

That way, if I want to change ALL the controls, I'd just have to change the "baseStyle" style, the rest would just inherit from it. (That's what BasedOn property those, you can also extend the base style if you create other setters inside of the inherited style)

Upvotes: 112

Chris Nicol
Chris Nicol

Reputation: 10366

For any styles in WPF, you should have a separate resource dictionary that contains the styles for your app.

If you want to have a single Font Size that's reused throughout the app then just create a style for that font size. You can either give it a unique name/key to use explicitly or you can set a targetType that will transcend throughout the app.

Explicit Key:

<Style
    x:Key="MyFontSize"
    TargetType="TextBlock">
    <Setter
        Property="FontSize"
        Value="10" />
</Style>

<Control
    Style="{StaticResource MyFontSize}" />

*Note this style can be used with controls that have contentPresenters

For all textblocks in the app:

<Style
    TargetType="TextBlock">
    <Setter
        Property="FontSize"
        Value="10" />
</Style>

<TextBlock
        Text="This text will be size 10" />

Upvotes: 7

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