ComboBox绑定到枚举，我做错了什么？ [英] ComboBox binding to enum, what did I do wrong?

问题描述

我已经搜索了，它似乎很容易绑定枚举到组合框，只是通过ObjectDataProvider从静态Enum.GetValues方法检索枚举值作为字符串列表，但我不能让它工作。错误是类型ContactExportType未找到。

I have searched around and it seems very easy to bind enums to combobox, just retrieve Enum values as a list of strings via an ObjectDataProvider from the static Enum.GetValues method, however i can't get it to work. The error is Type ContactExportType was not found.

我有一个名为ContactExportType的枚举，它驻留在Enums类上。这个类是CEM.Marketing.Objects命名空间的一部分。

I have an enum called ContactExportType, it resides on Enums class. This class is part of the CEM.Marketing.Objects namespace.

这是我有：

<UserControl 
 xmlns:local="clr-namespace:CEM.Marketing.Objects"
 xmlns:sys="clr-namespace:System;assembly=mscorlib">

<Grid>
<Grid.Resources>
        <ObjectDataProvider MethodName="GetValues"
                    ObjectType="{x:Type sys:Enum}"
                    x:Key="ContactExportTypes">
        <ObjectDataProvider.MethodParameters>
            <x:Type TypeName="local:ContactExportType" />
        </ObjectDataProvider.MethodParameters>

    </ObjectDataProvider>
    </Grid.Resources>

</Grid>
 <ComboBox 
        ItemsSource="{Binding {StaticResource ContactExportTypes}}"
...

感谢，
Angela

Thanks, Angela

推荐答案

要访问嵌套类型， +分隔符：

To access a nested type, you should use the "+" separator :

<ObjectDataProvider MethodName="GetValues"
                    ObjectType="{x:Type sys:Enum}"
                    x:Key="ContactExportTypes">
    <ObjectDataProvider.MethodParameters>
        <x:Type TypeName="local:Enums+ContactExportType" />
    </ObjectDataProvider.MethodParameters>

</ObjectDataProvider>

顺便说一下，有一个更简单的方法绑定到枚举的值， ObjectDataProvider。它是基于自定义标记扩展：

By the way, there is a simpler way to bind to the values of an enum, without using an ObjectDataProvider. It's based on a custom markup extension :

<ComboBox ItemsSource="{local:EnumValues local:Enums+ContactExportType}"/>

这里是EnumValues标记扩展的代码：

Here is the code for the EnumValues markup extension :

[MarkupExtensionReturnType(typeof(object[]))]
public class EnumValuesExtension : MarkupExtension
{
    public EnumValuesExtension()
    {
    }

    public EnumValuesExtension(Type enumType)
    {
        this.EnumType = enumType;
    }

    [ConstructorArgument("enumType")]
    public Type EnumType { get; set; }

    public override object ProvideValue(IServiceProvider serviceProvider)
    {
        if (this.EnumType == null)
            throw new ArgumentException("The enum type is not set");
        return Enum.GetValues(this.EnumType);
    }
}

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