这可能是一个无知的问题，但我不能确定，为什么我不能使用命名空间别名和扩展方法在一起。

This may be an ignorant question, but I'm unsure why I can not use namespace aliasing and extension methods together.

下面的示例工作得很好：

The following example works just fine:

的Program.cs

using System;
using ExtensionMethodTest.Domain;

namespace ExtensionMethodTest
{
    class Program
    {
        static void Main(string[] args)
        {
            var m = new Domain.MyClass();
            var result = m.UpperCaseName();
        }
    }
}

MyClass.cs

using System;

namespace ExtensionMethodTest.Domain
{
    public class MyClass
    {
        public string Name { get; set; }
    }
}

MyClassExtensions.cs

using System;

namespace ExtensionMethodTest.Domain
{
    public static class MyClassExtensions
    {
        public static string UpperCaseName (this MyClass myClass)
        {
            return myClass.Name.ToUpper();
        }
    }
}

然而，当我别名域在Program.cs中，如下所示：

However, when I alias domain as follows in Program.cs:

using Domain = ExtensionMethodTest.Domain;

扩展方法不再起作用。

The extension method no longer works..

这可以是相当令人沮丧，当我处理各种转换域对象签订合同的对象（比方说，我有4个域组件和4个合约总成），用于Web服务的使用。使用别名将是非常方便的，因为我可以别名如下，并继续使用各种扩展方法（如ToContract等）：

This can be rather frustrating when I'm dealing with converting various domain objects to contract objects (let's say I have 4 domain assemblies and 4 contract assemblies) for use in a web service. Using aliasing would be very handy as I could alias as follows and continue to use the various extension methods (such as ToContract, etc.):

using BillingContracts = Namespace.Billing.Contracts;
using IssuingContracts = Namespace.Issuing.Contracts;

等等...

etc...

我期待着答案。我敢肯定，这是简单的，但我为我的生活，想不通为什么它不工作。

I look forward to the answer.. I'm sure it's straight forward, but I, for the life of me, can't figure out why it doesn't work.

谢谢！

推荐答案

确认仍然增加的非别名 using语句：

Make sure to still add a non-aliased using statement:

的Program.cs

using System;
using ExtensionMethodTest.Domain; //DON'T FORGET A NON-ALIASED USING
using MyDomain = ExtensionMethodTest.Domain;

namespace ExtensionMethodTest
{
    class Program
    {
        static void Main(string[] args)
        {
            var m = new MyDomain.MyClass();
            var result = m.UpperCaseName();
        }
    }
}

MyClass.cs

using System;

namespace ExtensionMethodTest.Domain
{
    public class MyClass
    {
        public string Name { get; set; }
    }
}

MyClassExtensions.cs

using System;

namespace ExtensionMethodTest.Domain
{
    public static class MyClassExtensions
    {
        public static string UpperCaseName (this MyClass myClass)
        {
            return myClass.Name.ToUpper();
        }
    }
}