【WPF】動態設置Binding的ConverterParameter轉換器參數

問題：XAML中，想要在一個Bingding語句中再次Bingding。

Source="{Binding Path=Image,Converter={StaticResource UMatToBitmapSourceConverter},ConverterParameter={Binding IsMirror}}"

運行后會報錯XML解析異常：

解決辦法：改為使用MultiBinding的及其轉換器。

<Image.Source>
    <MultiBinding Converter="{StaticResource UMatToBitmapSourceConverter}">
        <Binding Path="Image"/>
        <Binding Path="IsMirror"/>
    </MultiBinding>
</Image.Source>

多綁定的轉換器，構造方法參數中object[] value即是多個Binding攜帶過來的值。用角標訪問這些數據，注意向下轉型的類型。

public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
{
    bool isMirror = false;
    if (values[1] != null)
    {
        isMirror = (bool)values[1];
    }
    try
    {
        if (values[0] is UMat)
        {
            var image = values[0] as UMat;
            return ChangeBitmapToImageSource(image.Bitmap, isMirror); // do what you want to do here！
        }
        else
        {
            return ChangeBitmapToImageSource(values[0] as System.Drawing.Bitmap);
        }
    }
    catch
    {
        return DependencyProperty.UnsetValue;
    }
}

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重要參考：

• http://stackoverflow.com/questions/15309008/binding-converterparameter
• http://www.cnblogs.com/yanchanggang/archive/2009/10/30/1592692.html