Partial class in different namespaces

问题

Can I create partial class in different namespaces? Will it work correct? e.x.:

class1.cs

namespace name1
{
    public partial class Foo
    {
        Bar1(){
            return 10;
        }
    }
}

class2.cs

namespace name1.name2
{
    public partial class Foo
    {
        Bar2(){
            return 100;
        }
    }
}

main.cs

using name1;
using name1.name2;

namespace mainClass
{
    public class mainClass
    {
        Foo classFoo = new Foo();
        int Count = classFoo.Bar1() + classFoo.Bar2();
        // Will Count = 110?
    }
}

What should I do to make it work? (if my example not correct)

回答1:

A class's name includes it's namespace, so name1.Foo and name1.name2.Foo are two completely separate types. So the short answer to your question is: No.

Why do you need to do something like this?

回答2:

Partial class is only possible in same namespace and same assembly.

Namespace could be in two different assemblies but partial class could not.

回答3:

Here are some point to consider while implementing the partial classes:-

Use partial keyword in each part of partial class.
Name of each part of partial class should be the same but source file name for each part of partial class can be different.
All parts of a partial class should be in the same namespace.
Each part of a partial class should be in the same assembly or DLL, in other words you can't create a partial class in source files of a different class library project.
Each part of a partial class has the same accessibility. (like private, public or protected)
If you inherit a class or interface on a partial class then it is inherited on all parts of a partial class.
If a part of a partial class is sealed then the entire class will be sealed.
If a part of partial class is abstract then the entire class will be considered an abstract class.

回答4:

This will not work. The compiler will give you an ambiguous name error on the Foo classFoo = new Foo(); line. For partial classes to work, they must be in the same namespace because the namespace is actually part of the fully qualified name of the type.

回答5:

Also, for static classes you can implement something like this with the help of fresh C# 6.0 using static feature.

Consider:

namespace SomeLogic1
{
    public static class Util
    {
        public static int Bar1()
        {
            return 1;
        }
    }
}

namespace SomeLogic2
{
    public static class Util
    {
        public static int Bar2()
        {
            return 2;
        }
    }
}

namespace GeneralStuff
{
    using SomeLogic1;
    using SomeLogic2;

    public class MainClass
    {
        public MainClass()
        {
            // Error CS0104
            // 'Util' is an ambiguous reference between 'SomeLogic1.Util' and 'SomeLogic2.Util'
            var result = Util.Bar1() + Util.Bar2(); 
        }
    }
}

Right, that does not compile, the error message is clear. To fix the situation you can directly specify namespaces (but you don't want this as far as I understand):

namespace GeneralStuff
{
    public class MainClass
    {
        public MainClass()
        {
            var result = SomeLogic1.Util.Bar1() + SomeLogic2.Util.Bar2(); 
        }
    }
}

OR you can apply using static feature this way:

namespace GeneralStuff
{
    using static SomeLogic1.Util;
    using static SomeLogic2.Util;

    public class MainClass
    {
        public MainClass()
        {
            var result = Bar1() + Bar2(); 
        }
    }
}

Perhaps it is ok to do this for some helper/utils classes. But partial classes are not the way, as other have noticed.

回答6:

Restrictions on partial classes and method from MSDN https://msdn.microsoft.com/en-us/library/wa80x488.aspx

来源：https://stackoverflow.com/questions/4504288/partial-class-in-different-namespaces

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