也是个很奇葩的问题了，有一个多值转换器IMultiValueConverter在ItemsControl里当成IValueConverter使用，编译不报错，可正常运行，但就是会阻塞ui。代码如下
xaml
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| <ItemsControl ItemsSource="{Binding Items}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<Border>
<Grid>
<TextBox
Text="{Binding Rate, Converter={StaticResource DataTransferRateUnitValuesConverter}}" />
</Grid>
</Border>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
|
csharp
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| public class DataTransferRateUnitValuesConverter : IMultiValueConverter
{
public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
{
if (parameter != null && parameter.ToString() == "bps" && values.Length == 1 && values[0] is double rate1)
{
return $"{DataUnitHelper.GetTransferRate(rate1)}";
}
if (values.Length == 2 && values[0] is string channelname && values[1] is double rate)
{
if (channelname.StartsWith("pps", StringComparison.CurrentCultureIgnoreCase))
{
return $"{rate:0.###} pps";
}
else
{
return $"{DataUnitHelper.GetTransferRate(rate)}";
}
}
return "0 bps";
}
public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
{
throw new NotImplementedException();
}
}
public class DataUnitHelper
{
private static readonly ulong TbLength = Convert.ToUInt64(Math.Pow(1024, 4));
private static readonly ulong GbLength = Convert.ToUInt64(Math.Pow(1024, 3));
private static readonly ulong MbLength = Convert.ToUInt64(Math.Pow(1024, 2));
private static readonly ulong KbLength = 1024;
private static readonly ulong TbpsLength = Convert.ToUInt64(Math.Pow(10, 12));
private static readonly ulong GbpsLength = Convert.ToUInt64(Math.Pow(10, 9));
private static readonly ulong MbpsLength = Convert.ToUInt64(Math.Pow(10, 6));
private static readonly ulong KbpsLength = Convert.ToUInt64(Math.Pow(10, 3));
public static string GetLength(ulong length)
{
if (length >= TbLength)
{
return (length * 1.0 / TbLength).ToString("0.###") + " TB";
}
if (length >= GbLength)
{
return (length * 1.0 / (GbLength)).ToString("0.###") + " GB";
}
if (length >= MbLength)
{
return (length * 1.0 / (MbLength)).ToString("0.###") + " MB";
}
if (length >= KbLength)
{
return (length * 1.0 / KbLength).ToString("0.###") + " KB";
}
return length + " B";
}
public static string GetTransferRate(double rate)
{
if (rate >= TbpsLength)
{
return (rate * 1.0 / TbpsLength).ToString("0.###") + " Tbps";
}
if (rate >= GbpsLength)
{
return (rate * 1.0 / (GbpsLength)).ToString("0.###") + " Gbps";
}
if (rate >= MbpsLength)
{
return (rate * 1.0 / (MbpsLength)).ToString("0.###") + " Mbps";
}
if (rate >= KbpsLength)
{
return (rate * 1.0 / KbpsLength).ToString("0.###") + " Kbps";
}
return rate.ToString("0.###") + " bps";
}
}
|
经查阅资料，原来wpf做了自动兼容容错：把IMultiValueConverter当成 IValueConverter用，wpf不会崩溃，只会默默返回 DependencyProperty.UnsetValue
故而ui阻塞过程：
用错转换器 → WPF 引擎进入无限兼容 / 重试逻辑 → ui线程死循环阻塞
当然，改过来就行了。
我是因为这个转换器原本是IValueConverter，由于需求变化，改成了IMultiValueConverter，但妙就秒在这个转换器很多地方在用，因为不会显式的提醒编译报错，故而遗漏这个，这里也是很奇怪，其他的地方没有ItemsControl包裹确实是会提醒报错地方的，悲啊，最后定位到这个转换器全局查找才找到的。