Release UnmanagedMemoryStream Resources

Environment

Product	Telerik UI for WPF
Version	2023.3.1010

Description

UnmanagedMemoryStream objects are stacking up in memory and never released on refresh of Telerik controls. For example, when resetting the ItemsSource of RadGridView. The issues occurs in newer Telerik themes - Material and later.

This happens because of a memory leak in WPF. In the Telerik's context this manifests when using the RadGlyph controls, which registers the custom Telerik font (TelerikWebUI) which holds the glyph icons.

Solution

To prevent the memory leak, unregister the TelerikWebUI font using the RadGlyph API and then re-register again in the App class. Make sure to use the absolute path to the .ttf file when registering the font.

public App()  
{ 
    var glyphType = typeof(RadGlyph); 
    var unregisterMethod = glyphType.GetMethod("UnregisterFont", System.Reflection.BindingFlags.Static | System.Reflection.BindingFlags.NonPublic); 
    unregisterMethod.Invoke(null, new object[1] { "TelerikWebUI" }); 
 
    ParserContext parserContext = new ParserContext(); 
    parserContext.XmlnsDictionary.Add("", "http://schemas.microsoft.com/winfx/2006/xaml/presentation"); 
    parserContext.XmlnsDictionary.Add("x", "http://schemas.microsoft.com/winfx/2006/xaml"); 
    string processDirPath = System.IO.Path.GetDirectoryName(System.Diagnostics.Process.GetCurrentProcess().MainModule.FileName); 
    string projectRootDir = System.IO.Path.GetFullPath(processDirPath + @"......"); 
    var telerikFontString = string.Format("<FontFamily>{0}\TelerikWebUI.ttf#TelerikWebUI</FontFamily>", projectRootDir); 
    var telerikFont = (FontFamily)System.Windows.Markup.XamlReader.Parse(telerikFontString, parserContext); 
    RadGlyph.RegisterFont(telerikFont, "TelerikWebUI"); 
} 

The TelerikWebUI.ttf file can be found in the Telerik UI for WPF source code that can download from the product page. The file is under the following directory:

\Core\Controls\Themes\Fonts\old\TelerikWebUI.ttf