Fast ArgumentNullException with attributes. It is possible?

Question

Hi.

Is there any fast way to verify null arguments via attributes or something?

Convert this:

public void Method(type arg1,type arg2,type arg3)
{
     if (arg1== null) throw new ArgumentNullException("arg1");
     if (arg2== null) throw new ArgumentNullException("arg2");
     if (arg3== null) throw new ArgumentNullException("arg3");
     //Business Logic
}

Into something like this:

[VerifyNullArgument("arg1","arg2","arg3")]
public void Method(type arg1,type arg2,type arg3)
{
      //Business Logic
}

Ideas? thanks guys.

Answer 1

You're looking for PostSharp.

Answer 2

There are Code Contracts built into .NET 4. That's probably as close as you'll get. There's quite a bit more information at DevLabs if you chose to go this route.

Answer 3

not an attribute, but similar idea:

class SomeClass
{
    public static void VerifyNullArgument(params object objects)
    {
        if (objects == null)
        {
            throw new ArgumentNullException("objects");
        }

        for (int index = 0; index < objects.Lenght; index++)
        {
            if (objects[index] == null)
            {
                throw new ArgumentException("Element is null at index " + index,
                    "objects");
            }
        }
    }
}

then in your example method

public void Method(type arg1,type arg2,type arg3)
{
    SomeClass.VerifyNullArgument(arg1, arg2, arg3);
    //Business Logic
}

Answer 4

When you have the Ultimate edition of Visual Studio 2010, I think Code Contracts is the way to go. Otherwise you might take a look at the CutingEdge.Conditions library (shameless plug). It has a fluent interface. There are people that prefer it over Code Contracts :-). Here is an example:

public void Method(type arg1, type arg2, params type[] col)
{
    Condition.Requires(arg1, "arg1").IsNotNull();
    Condition.Requires(arg2, "arg2").IsNotNull();
    Condition.Requires(col, "col")
        .IsNotNull()
        .IsNotEmpty()
        .DoesNotContain(null);

    //Business Logic
}