Can I use a namespace for a specific block of code in C#?

Question

I just have a point of curiosity. I'm working with SSRS and calling its SOAP methods. I've got stubs generated / Web references created and that's all working fine and I can make web service calls OK.

The problem: the two classes generated from the WSDLs, ReportService2005 and ReportExecution, have some overlapping class definitions, such as ParameterValue, DataSourceCredentials, ReportParameter.

In C#, is there a way of saying, "For this block of code in the method, use this namespace?"

Pseudo / mostly build-error code:

use-this-namespace (ReportService2005)
{
    ParameterValue[] values = null;
    DataSourceCredentials[] credentials = null;
    ReportParameter[] parameters;
}

I understand that I can just write out of the full name, ReportService2005.ParameterValue[] values = null. Or I can alias the two classes at the top before my class/controller declaration. It's just something I'm curious about.

Madonna

Cool. Thanks, guys. I oddly find it fun to learn about the syntax of different languages. I'll admit it, I'm a geek. – Madonna

A namespace per method would be especially handy when using libraries which provide extension methods for core types like String (for example Flurl [tmenier.github.io/Flurl/]) which flood Intellisense for the entire code file. – Bellman

Answer 1

As others have written, I don't think this is possible. But what you can do, is to alias the full namespaces instead of each single class you want to use, e.g:

using rs = ReportService2005;
using re = ReportExecution;

// ...

rs.ParameterValue[] values = null;
rs.DataSourceCredentials[] credentials = null;
rs.ReportParameter[] parameters;
re.ParameterValue v2 = ...;

Irons

Answer 2

Another little-known C# feature that might interest you, and is similar to Martin's answer, is essentially aliasing a class in the Imports blocks:

using ListOfDictionary = System.Collections.Generic.List<System.Collections.Generic.Dictionary<string, string>>;

and declare it as

ListOfDictionary list = new ListOfDictionary();

Note This feature, and sample, were found in another question; specifically: Hidden Features of C#?

Deductive

This is pretty cool. Having to publish the alias in every file is a big detraction, though. Something like this that works namespace-wide would be very useful. – Effuse

If it's something you really need to use widely then it might be better to inherit. This kind of aliasing is handy for single-use, particularly because you don't have to leave the class file to figure out where this unknown type comes from. – Deductive

Answer 3

While not relevant for working with Namespaces, or C#, VB.NET supports the With keyword which can be used as a shortcut for accessing members of an object:

SomeReallyLongName.Property1 = 1
SomeReallyLongName.Property2 = 2
SomeReallyLongName.Property3 = 3
SomeReallyLongName.Property4 = 4
SomeReallyLongName.Property5 = 5

Can be rewritten as:

With SomeReallyLongName
    .Property1 = 1
    .Property2 = 2
    .Property3 = 3
    .Property4 = 4
    .Property5 = 5
End With

It's not in C#, as you can get very close to the same behavior using other approached:

• Using shorter variable names
• Using imports-aliasing (Such as Martin suggested)

Deductive

Oh, interesting. Although I don't use VB.NET, still cool to know. Thanks. – Madonna

Answer 4

What you can do, is mark your class as partial:

public partial class MyWebServiceClass

in your main source file, and create a second source file with the method where you want to use the other namespace

// MyWebServiceClass.usingMethods.cs

using ReportService2005;
public partial class MyWebServiceClass
{
    // methods...
}

Vinia

Granted, you still can't mix default namespaces within one method, so use the other suggestions here, but this way, you can separate methods if you want to have a default namespace for one or two methods only, say. – Vinia

Answer 5

I don't think you can do that. You must specify Fully Qualified name to do that.

Engineer

Answer 6

Unfortunately not. There's no such syntax to address this need.

Sinew

Answer 7

If the overlapping classes are identical (not just named the same) and share the same XML namespace, etc., then you may be able to take advantage of the wsdl.exe tool's sharetypes feature to generate both of your web service proxies so that they share the same type definitions for those overlapping classes.

http://msdn.microsoft.com/en-us/library/7h3ystb6%28VS.80%29.aspx

Check out the "/sharetypes" option to see if that works for your situation.

Alewife

Oh I didn't realize. I've been using VS2010's Web Reference tool. I'll give it a try. – Madonna

I believe the VS proxy generator (the web reference tool) actually uses the wsdl.exe tool behind the scenes. If that option works for you, then great. The downside is that if your web services change, then you will need to run the command again instead of just right-clicking on the web reference in visual studio and choosing "Update". However, that shouldn't be too bad. You could put the command in a batch file or a build script to simplify the process. – Selection

Answer 8

AFAIK it can't be done

Kickoff

Answer 9

Maybe not exactly within the scope of the block, but you could do it within a namespace. Assumes you have some classes with the same name but under different name space (maybe you are doing some refactor or what not):

• MyStuff.Legacy.Hello
• MyStuff.NG.Hello

And you want to only use the new one without transitioning everything else over to NG, then

using MyStuff.Legacy; // <= You still use all the old stuff

namespace MyStuff
{
    // but only want to use this new one
    using Hello = MyStuff.NG.Hello;
    ...

Everything within that namespace scope would reference MyStuff.NG.Hello when you call Hello.

Heliostat