c# - 仅当文件存在时才加载资源字典

Question

有没有办法只在资源文件存在的情况下加载资源字典？在下面的例子中，我希望只在文件“Resources/AdditionalStyles.xaml”存在时允许使用资源字典

<ResourceDictionary>
            <ResourceDictionary.MergedDictionaries>
                <ResourceDictionary Source="Resources/Styles.xaml" />
                <ResourceDictionary Source="Resources/AdditionalStyles.xaml" />
            </ResourceDictionary.MergedDictionaries>

Answer 1

您可以覆盖 App.xaml.cs 中的 OnStartup 方法，然后检查文件是否存在，如果存在则加载它:

protected override void OnStartup(StartupEventArgs e)
{
    var fileName = Environment.CurrentDirectory() + @"\Resources\AdditionalStyles.xaml";

    // Check if the AdditionalStyles.xaml file exists
    if (File.Exists(fileName)
    {
        try
        {
            // try and load the file as a dictionary and add it the dictionaries
            var additionalStylesDict = (ResourceDictionary)XamlReader.Load(fs);
            Resources.MergedDictionaries.Add(additionalStylesDict);
        }
        catch (Exception ex)
        {
            // something went wrong loading the resource file
        }
    }

    // any other stuff on startup

    // call the base method
    base.OnStartup(e);
}