如何强制对系统类型使用自定义UITypeEditor

问题是它注意到 TypeConverter 支持枚举值。我们需要禁用它;注意我们也可以 继承 从默认实现中获取诸如颜色预览绘制之类的内容(C#中的示例,但应易于翻译):

class MyColorEditor : ColorEditor {
    public override UITypeEditorEditStyle GetEditStyle(
        ITypeDescriptorContext context) {
         return UITypeEditorEditStyle.Modal;
    }
    public override object  EditValue(
       ITypeDescriptorContext context, IServiceProvider provider, object value) {
        MessageBox.Show(
              "We could show an editor here, but you meant Green, right?");
       return Color.Green;
    }
}
class MyColorConverter : ColorConverter { // reference: System.Drawing.Design.dll
    public override bool GetStandardValuesSupported(
            ITypeDescriptorContext context) {
        return false;
    }
}
class TestObject
{
    [Category("Order Colour"), Browsable(true), DisplayName("Colour")]
    [Description("The background colour for orders from this terminal")]
    [Editor(typeof(MyColorEditor), typeof(UITypeEditor))]
    [TypeConverter(typeof(MyColorConverter))]
    public Color Colour {get;set;}
}

全部的 Color 属性,也有一种方法可以这样做,您不需要装饰每个属性;在应用程序的初始化代码中的某个地方,执行:

TypeDescriptor.AddAttributes(typeof(Color),
    new EditorAttribute(typeof(MyColorEditor), typeof(UITypeEditor)),
    new TypeConverterAttribute(typeof(MyColorConverter)));

我需要实现一个TypeConverter来强制支持的GetStandardValuesSupported返回false。

然后我就可以去掉颜色属性,直接使用。

<CategoryAttribute("Order Colour"), _
Browsable(True), _
DisplayName("Custom Colour to Use"), _
Description("The background colour for orders from this terminal"), _
EditorAttribute(GetType(IKMDependency.ColourSelectorEditor), GetType(System.Drawing.Design.UITypeEditor)), _
TypeConverter(GetType(ColourTypeConverter))> _
Public Property Colour() As Color
    Get
        Return mColor
    End Get
    Set(ByVal value As Color)
        If mColor <> value Then
            mColor = value
            mIsDirty = True
        End If
    End Set
End Property

这有点难看,因为框中的颜色表示为所选的颜色,但文本打印在PropertyGridCell的其余部分中,因此我还向转换器添加了一些重写以仅返回空字符串。(我宁愿把整个牢房都涂成这种颜色,而不仅仅是小盒子)。

转换器类。

Public Class ColourTypeConverter
    Inherits TypeConverter

    Public Overrides Function GetStandardValuesSupported(ByVal context As System.ComponentModel.ITypeDescriptorContext) As Boolean
        Return False
    End Function

    Public Overrides Function CanConvertFrom(ByVal context As System.ComponentModel.ITypeDescriptorContext, ByVal sourceType As System.Type) As Boolean
        If sourceType Is GetType(String) Then Return False
        Return MyBase.CanConvertFrom(context, sourceType)
    End Function

    Public Overrides Function ConvertTo(ByVal context As System.ComponentModel.ITypeDescriptorContext, ByVal culture As System.Globalization.CultureInfo, ByVal value As Object, ByVal destinationType As System.Type) As Object
        If destinationType Is GetType(String) Then Return String.Empty
        Return MyBase.ConvertTo(context, culture, value, destinationType)
    End Function

    Public Overrides Function ConvertFrom(ByVal context As System.ComponentModel.ITypeDescriptorContext, ByVal culture As System.Globalization.CultureInfo, ByVal value As Object) As Object
        Return MyBase.ConvertFrom(context, culture, value)
    End Function

    Public Overrides Function CanConvertTo(ByVal context As System.ComponentModel.ITypeDescriptorContext, ByVal destinationType As System.Type) As Boolean
        If destinationType Is GetType(String) Then Return False
        Return MyBase.CanConvertTo(context, destinationType)
    End Function
End Class