MVVMCross ValueConverter Bool 到 MvxColor/Color

Question

我试图为 MVVMCross 实现 ValueConverter，但显然它没有像我预期的那样工作。所以目前我刚刚得到另一个属性，它为我进行转换（MvxColor 到 TextColor）并将它绑定到我的布局。 但是ofc我宁愿使用值转换器，所以也许你知道我做错了什么：

我当前遇到的绑定错误：

    06-09 16:29:29.820 I/MvxBind (16312):  61,64 Problem seen during binding execution for binding TextColor for Changed - problem InvalidCastException: Specified cast is not valid.
06-09 16:29:29.820 I/MvxBind (16312):     at MvvmCross.Plugins.Color.Droid.BindingTargets.MvxTextViewTextColorBinding.SetValueImpl (System.Object target, System.Object value) [0x0000a] in <filename unknown>:0 
06-09 16:29:29.820 I/MvxBind (16312):   at MvvmCross.Binding.Bindings.Target.MvxConvertingTargetBinding.SetValue (System.Object value) [0x00088] in <filename unknown>:0 
06-09 16:29:29.820 I/MvxBind (16312):   at MvvmCross.Binding.Bindings.MvxFullBinding.UpdateTargetFromSource (System.Object value) [0x00024] in <filename unknown>:0 
MvxBind:Error: 61,64 Problem seen during binding execution for binding TextColor for Changed - problem InvalidCastException: Specified cast is not valid.
06-09 16:29:29.820 I/mono-stdout(16312): MvxBind:Error: 61,64 Problem seen during binding execution for binding TextColor for Changed - problem InvalidCastException: Specified cast is not valid.
06-09 16:29:29.820 I/mono-stdout(16312):      at MvvmCross.Plugins.Color.Droid.BindingTargets.MvxTextViewTextColorBinding.SetValueImpl (System.Object target, System.Object value) [0x0000a] in <filename unknown>:0 
      at MvvmCross.Plugins.Color.Droid.BindingTargets.MvxTextViewTextColorBinding.SetValueImpl (System.Object target, System.Object value) [0x0000a] in <filename unknown>:0 
  at MvvmCross.Binding.Bindings.Target.MvxConvertingTargetBinding.SetValue (System.Object value) [0x00088] in <filename unknown>:0 
06-09 16:29:29.830 I/mono-stdout(16312):   at MvvmCross.Binding.Bindings.Target.MvxConvertingTargetBinding.SetValue (System.Object value) [0x00088] in <filename unknown>:0 
  at MvvmCross.Binding.Bindings.MvxFullBinding.UpdateTargetFromSource (System.Object value) [0x00024] in <filename unknown>:0 
06-09 16:29:29.830 I/mono-stdout(16312):   at MvvmCross.Binding.Bindings.MvxFullBinding.UpdateTargetFromSource (System.Object value) [0x00024] in <filename unknown>:0 
[0:] MvxBind:Error: 61,64 Problem seen during binding execution for binding TextColor for Changed - problem InvalidCastException: Specified cast is not valid.
      at MvvmCross.Plugins.Color.Droid.BindingTargets.MvxTextViewTextColorBinding.SetValueImpl (System.Object target, System.Object value) [0x0000a] in <filename unknown>:0 
  at MvvmCross.Binding.Bindings.Target.MvxConvertingTargetBinding.SetValue (System.Object value) [0x00088] in <filename unknown>:0 
  at MvvmCross.Binding.Bindings.MvxFullBinding.UpdateTargetFromSource (System.Object value) [0x00024] in <filename unknown>:0 

我的布局片段：

<EditText
      android:layout_width="fill_parent"
      android:layout_height="wrap_content"
      android:layout_weight="1"
      android:singleLine="true"
      android:inputType="numberDecimal|numberSigned"
      android:textColor="@color/schaefflerlightgreen"
      local:MvxBind="TextColor Changed,Converter=MvxBoolToColorValueConverter" />

我试过的两个转换器类：

    public class MvxBoolToMvxColorValueConverter: MvxColorValueConverter<bool>
{

    protected override MvxColor Convert(bool value, object parameter, CultureInfo culture)
    {
        if (value)
        {
            // FF0000
            return new MvxColor(255, 0, 0);
        }
        //227D41
        return new MvxColor(34, 125, 65);
    }
}

    public class MvxBoolToColorValueConverter : MvxValueConverter<bool, Color>
{

    protected override Color Convert(bool value, Type targetType, object parameter, CultureInfo culture)
    {
        if (value)
        {
            // FF0000
            return new Color(255, 0, 0);
        }
        //227D41
        return new Color(34, 125, 65);
    }

}

问题是绑定通常使用 MvxColor-Property，只是转换似乎是一个问题。所以可能我只是错过了一些东西。

非常感谢您的帮助。

伊迪丝：还有财产……

public bool Changed { get { return m_sValue != m_sSyncValue; } }

Answer 1

从绑定中的转换器名称中去掉 Mvx-prefix 和 ValueConverter-suffix：

改变

local:MvxBind="TextColor Changed,Converter=MvxBoolToColorValueConverter" />

到

local:MvxBind="TextColor Changed,Converter=BoolToColor" />

documentation for ValueConverters 中描述了此行为：

此扫描定位所有实现 IMvxValueConverter 的可实例化类 在您的程序集中创建每个注册的实例 名称为 的实例去除了任何 Mvx 前缀和任何 ValueConverter 或 Converter 后缀。因此，例如，以下 类名都将使用相同的 ValueConverter 名称注册 “Foo”：

Foo, FooValueConverter, FooConverter, MvxFooValueConverter, MvxFooConverter