在WPF中我们想使用ttf字体作为嵌入式资源，无需将它们复制或安装到系统中，也无需实际将它们写入磁盘。没有内存泄漏问题。
没有详细说明的解决方案：
如何在 WPF 应用程序中包含外部字体而不安装它
由于 WPF 内存泄漏，在这种情况下可用：
使用 Font 时 WPF TextBlock 内存泄漏
在 GDI 中只能通过以下方式从内存和进程安装字体添加FontMemResourceEx。由于这会安装该进程的字体，因此它也应该适用于 WPF，但似乎存在问题FontFamily我们通过安装字体后得到的AddFontMemResourceEx. E.g.:
var font = new FontFamily("Roboto");
这是有效的，因为它不会给出任何错误，但字体实际上没有改变，一些行间距和其他指标发生了变化，但字体看起来完全像Segoe UI因为某些原因。
那么问题是如何使用安装的字体AddFontMemResourceEx in WPF?
PS：这里是P/Invoke代码：
const string GdiDllName = "gdi32";
[DllImport(GdiDllName, ExactSpelling= true)]
private static extern IntPtr AddFontMemResourceEx(byte[] pbFont, int cbFont, IntPtr pdv, out uint pcFonts);
public static void AddFontMemResourceEx(string fontResourceName, byte[] bytes, Action<string> log)
{
var handle = AddFontMemResourceEx(bytes, bytes.Length, IntPtr.Zero, out uint fontCount);
if (handle == IntPtr.Zero)
{
log?.Invoke($"Font install failed for '{fontResourceName}'");
}
else
{
var message = $"Font installed '{fontResourceName}' with font count '{fontCount}'";
log?.Invoke(message);
}
}
此代码成功并显示如下日志消息：
Font installed 'Roboto-Regular.ttf' with font count '1'
将嵌入资源加载为字节数组的支持代码：
public static byte[] ReadResourceByteArray(Assembly assembly, string resourceName)
{
using (var stream = assembly.GetManifestResourceStream(resourceName))
{
var bytes = new byte[stream.Length];
int read = 0;
while (read < bytes.Length)
{
read += stream.Read(bytes, read, bytes.Length - read);
}
if (read != bytes.Length)
{
throw new ArgumentException(
$"Resource '{resourceName}' has unexpected length " +
$"'{read}' expected '{bytes.Length}'");
}
return bytes;
}
}
这意味着安装嵌入字体可以像这样完成assembly是包含嵌入字体资源的程序集EMBEDDEDFONTNAMESPACE是嵌入资源的命名空间，例如SomeProject.Fonts:
var resourceNames = assembly.GetManifestResourceNames();
string Prefix = "EMBEDDEDFONTNAMESPACE" + ".";
var fontFileNameToResourceName = resourceNames.Where(n => n.StartsWith(Prefix))
.ToDictionary(n => n.Replace(Prefix, string.Empty), n => n);
var fontFileNameToBytes = fontFileNameToResourceName
.ToDictionary(p => p.Key, p => ReadResourceByteArray(assembly, p.Value));
foreach (var fileNameBytes in fontFileNameToBytes)
{
AddFontMemResourceEx(fileNameBytes.Key, fileNameBytes.Value, log);
}
我不知道这是否正是您想要的，但我有一个解决方案，您可以将字体用作Resource在你的解决方案中。
fonts你想要作为Resource.MarkupExtension called FontExplorer
XAML Example当。。。的时候application开始并且FontExplorer第一次使用，会缓存所有fonts您拥有的资源。此后，每当您需要其中之一时，都会使用缓存将其返还。
public class FontExplorer : MarkupExtension
{
// ##############################################################################################################################
// Properties
// ##############################################################################################################################
#region Properties
// ##########################################################################################
// Public Properties
// ##########################################################################################
public string Key { get; set; }
// ##########################################################################################
// Private Properties
// ##########################################################################################
private static readonly Dictionary<string, FontFamily> _CachedFonts = new Dictionary<string, FontFamily>();
#endregion
// ##############################################################################################################################
// Constructor
// ##############################################################################################################################
#region Constructor
static FontExplorer()
{
foreach (FontFamily fontFamily in Fonts.GetFontFamilies(new Uri("pack://application:,,,/"), "./Fonts/"))
{
_CachedFonts.Add(fontFamily.FamilyNames.First().Value, fontFamily);
}
}
#endregion
// ##############################################################################################################################
// methods
// ##############################################################################################################################
#region methods
public override object ProvideValue(IServiceProvider serviceProvider)
{
return ReadFont();
}
private object ReadFont()
{
if (!string.IsNullOrEmpty(Key))
{
if (_CachedFonts.ContainsKey(Key))
return _CachedFonts[Key];
}
return new FontFamily("Comic Sans MS");
}
#endregion
}
<Window x:Class="WpfApp1.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:WpfApp1"
mc:Ignorable="d"
d:DataContext="{d:DesignInstance local:MainWindow}"
Title="MainWindow" Height="450" Width="800">
<Window.Style>
<Style TargetType="local:MainWindow">
<Setter Property="FontFamily" Value="{local:FontExplorer Key='Candle Mustard'}"/>
<Style.Triggers>
<Trigger Property="Switch" Value="True">
<Setter Property="FontFamily" Value="{local:FontExplorer Key=Roboto}"/>
</Trigger>
</Style.Triggers>
</Style>
</Window.Style>
<Grid x:Name="grid">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<StackPanel Orientation="Vertical" VerticalAlignment="Center" HorizontalAlignment="Center" Grid.Column="0">
<TextBlock Text="Hello World" FontFamily="{local:FontExplorer Key='Candle Mustard'}"/>
<TextBlock Text="Hello World" FontFamily="{local:FontExplorer Key=Roboto}"/>
<TextBlock Text="Hello World"/>
<TextBlock Text="Hello World"/>
<TextBlock Text="Hello World"/>
<TextBlock Text="Hello World"/>
<TextBlock Text="Hello World"/>
<TextBlock Text="Hello World"/>
<TextBlock Text="Hello World"/>
<TextBlock Text="Hello World"/>
<TextBlock Text="Hello World"/>
<TextBlock Text="Hello World"/>
</StackPanel>
<StackPanel Orientation="Vertical" VerticalAlignment="Center" HorizontalAlignment="Center" Grid.Column="1" x:Name="Panel"/>
</Grid>
</Window>
public partial class MainWindow : Window
{
public bool Switch
{
get => (bool)GetValue(SwitchProperty);
set => SetValue(SwitchProperty, value);
}
/// <summary>
/// The <see cref="Switch"/> DependencyProperty.
/// </summary>
public static readonly DependencyProperty SwitchProperty = DependencyProperty.Register("Switch", typeof(bool), typeof(MainWindow), new PropertyMetadata(false));
private readonly DispatcherTimer _Timer;
public MainWindow()
{
InitializeComponent();
_Timer = new DispatcherTimer();
_Timer.Interval = TimeSpan.FromMilliseconds(50);
_Timer.Tick += (sender, args) =>
{
Switch = !Switch;
Panel.Children.Add(new TextBlock {Text = "I'm frome code behind"});
if(Panel.Children.Count > 15)
Panel.Children.Clear();
};
_Timer.Start();
}
// ##############################################################################################################################
// PropertyChanged
// ##############################################################################################################################
#region PropertyChanged
/// <summary>
/// The PropertyChanged Eventhandler
/// </summary>
public event PropertyChangedEventHandler PropertyChanged;
/// <summary>
/// Raise/invoke the propertyChanged event!
/// </summary>
/// <param name="propertyName"></param>
protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
#endregion
}
正如您在预览中看到的，memory usage后从 83,2MB 减少到 82,9 MBGC做它的工作。
