Reputation: 1267
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)
Upvotes: 85
Views: 57200
Reputation: 706
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.
Upvotes: 19
Reputation: 27036
I am assuming your main goal was to distribute the methods amongst different namespaces, otherwise it would have been trivial (put everything in one class whether partial or not and you're done).
So the assumed objectives are:
Bar1
in namespace name1
and Bar2
in namespace name1.name2
ClsFoo
You can't achieve this with partial classes, but you can achieve it in a different way: if you use extension methods and bind them to a particular class, here ClsFoo
, then you can do the following:
using SomeOtherNamespace;
using name1;
using name1.name2;
namespace mainClass
{
public static class mainClass
{
public static void Main()
{
var classFoo = new ClsFoo();
var count = classFoo.Bar1() + classFoo.Bar2();
Console.WriteLine($"count = {count}"); // output is 110
} // main
} // class
} // namespace
namespace SomeOtherNamespace
{
public class ClsFoo
{
// does not need to contain any code
} // class
} // namespace
namespace name1
{
public static class FooExt
{
public static int Bar1(this ClsFoo foo)
{
return 10;
} // method
} // class
} // namespace
namespace name1.name2
{
public static class FooExt
{
public static int Bar2(this ClsFoo foo)
{
return 100;
} // method
} // class
} // namespace
This way, you declare an empty class ClsFoo
and then write some extension methods Bar1()
and Bar2()
, which reside in different namespaces and static extension classes.
Note: The extension classes may have the same name FooExt
as long as they are in different namespaces, of course you can also give them different names like FooExt1
and FooExt2
if you like - and the example will still work; even in older versions of C#.
Upvotes: 1
Reputation: 4127
Partial class is only possible in same namespace and same assembly.
Namespace could be in two different assemblies but partial class could not.
Upvotes: 35
Reputation: 2142
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.
Upvotes: 5
Reputation: 399
Restrictions on partial classes and method from MSDN https://msdn.microsoft.com/en-us/library/wa80x488.aspx
Upvotes: 2
Reputation: 5239
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.
Upvotes: 7
Reputation: 19872
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?
Upvotes: 109