我应该在 App.xaml 中声明转换器还是作为每个文件的资源? [英] Should I declare converters in App.xaml or as a per-file resource?

问题描述

在 WPF 应用程序中声明转换器时，我应该:

When declaring converters in a WPF application, should I:

1. 在 App.xaml(即在 )中声明所有我的转换器，以便它可用于整个应用程序
2. 在 Page/Window/ResourceDictionary/UserControl 等中只声明需要的转换器>资源部分
3. 完全不同的东西

1. Declare all my converters in the App.xaml (i.e. in <Application.Resources/>) so it's available to the entire application
2. Declare only needed converters for each Page/Window/ResourceDictionary/UserControl etc. in their Resources section
3. Something else entirely

关于可读性，方法 1 对我来说似乎是最好的，但我的问题是关于性能的.哪种方法在性能、内存等方面的资源效率最高?

Regarding readability, method 1 seems the best to me, but my question is about performance. Which method is the most resource efficient in terms of performance, memory, etc.?

推荐答案

好吧，我只是根本不在 xaml 中声明它们.相反，我还从 MarkupExtension 派生了我的转换器.像这样:

Well, I just don't declare them in xaml at all. Instead, I additionally derive a converter of mine from MarkupExtension. Like this:

public class MyValueConverter : MarkupExtension, IValueConverter
{
    private static MyValueConverter _converter = null;
    public override object ProvideValue(IServiceProvider serviceProvider)
    {
        if (_converter == null) _converter = new MyValueConverter();    
        return _converter;
    }

    public object Convert
     (object value, Type targetType, object parameter, CultureInfo culture) { }
    public object ConvertBack
     (object value, Type targetType, object parameter, CultureInfo culture) { }
}

这让我可以在任何地方使用我的转换器，就像这样:

This allows me to use my converter anywhere, like this:

Source="{Binding myValue, Converter={converters:MyValueConverter}}"

其中转换器是我在其中声明转换器的命名空间.

where converters is the namespace in which I have declared my converter.

仅从旧的 stackoverflow 线程中学到了这个技巧.

Learned this trick from an old stackoverflow thread only.

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