WPF中通过字体名称正确调用Roboto字体的问题求助

Let me break down what's going on here and how to fix it:

First, the core problem is that the Roboto fonts you downloaded from dafont have inconsistent internal metadata—this is super common with third-party packaged fonts. WPF doesn't care about your file names; it relies on the family name and subfamily/weight metadata embedded inside the font files.

Looking at your character map results:

• Roboto-Bold.ttf and Roboto-Regular.ttf share the same family name (Roboto), but they have different weights (Bold vs. Regular/Normal)
• Roboto-Medium.ttf incorrectly shows up as Roboto Lt (this is a bug in the font packaging, not how Roboto is supposed to work)

Step 1: Use Official Roboto Fonts (Critical Fix) #

Dafont's version is messed up. Head to the official source to get properly packaged Roboto files—every weight (Regular, Medium, Bold) will have the same family name Roboto, with distinct subfamily weights (Regular, Medium, Bold). This will make WPF recognize them as part of the same font family, so you can switch weights easily.

Step 2: Correct Your XAML Styling #

Once you have the official fonts in your Fonts folder (with Build Action set to Resource), update your styles to use a single font family reference, and control weight via the FontWeight property:

<Window.Resources>
    <!-- Roboto Bold -->
    <Style x:Key="RobotoBold">
        <Setter Property="TextElement.FontFamily" Value="pack://application:,,,/Main;component/Fonts/#Roboto" />
        <Setter Property="TextElement.FontWeight" Value="Bold" />
    </Style>

    <!-- Roboto Medium -->
    <Style x:Key="RobotoMedium">
        <Setter Property="TextElement.FontFamily" Value="pack://application:,,,/Main;component/Fonts/#Roboto" />
        <Setter Property="TextElement.FontWeight" Value="Medium" />
    </Style>

    <!-- Roboto Regular -->
    <Style x:Key="RobotoRegular">
        <Setter Property="TextElement.FontFamily" Value="pack://application:,,,/Main;component/Fonts/#Roboto" />
        <Setter Property="TextElement.FontWeight" Value="Normal" />
    </Style>
</Window.Resources>

Step 3: Verify Available Weights (Debugging Tip) #

If you're still unsure which weights WPF recognizes, add this code to your Window_Loaded event to list all available typefaces in the Roboto family:

private void Window_Loaded(object sender, RoutedEventArgs e)
{
    var robotoFamily = new FontFamily("pack://application:,,,/Main;component/Fonts/#Roboto");
    foreach (var typeface in robotoFamily.GetTypefaces())
    {
        Console.WriteLine($"Weight: {typeface.Weight}, Style: {typeface.Style}");
    }
}

This will output something like:

Weight: Normal, Style: Normal
Weight: Medium, Style: Normal
Weight: Bold, Style: Normal

Why Your Original Code Failed #

• When multiple font files share the same family name, WPF groups them into a single font family. You can't reference them by different family names (like #Roboto Bold)—you have to use FontWeight to pick the right variant.
• The Roboto Lt name for your Medium font was a packaging error from dafont, which is why that style didn't work as expected.

内容的提问来源于stack exchange，提问作者Mc_Topaz