'System.Guid'不是属性类

Question

I am creating a new dll application with Visual Studio 2013 based on .net 4.5. When trying to define the Guid attribute on my class like this:

[Guid("4245366B-0484-4A41-A2E8-C7D9FC3A4ED7")]

The compiler gives me the error

'System.Guid' is not an attribute class.

Any idea what's missing?

Answer 1

You must add reference to the System.Runtime.InteropServices , like this:

using System.Runtime.InteropServices;

or state the full name for the class:

[System.Runtime.InteropServices.Guid("4245366B-0484-4A41-A2E8-C7D9FC3A4ED7")]

or use class name with postfix Attribute :

[GuidAttribute("4245366B-0484-4A41-A2E8-C7D9FC3A4ED7")]

or use full class name with postfix Attribute :

[System.Runtime.InteropServices.GuidAttribute("4245366B-0484-4A41-A2E8-C7D9FC3A4ED7")]

You can find more information on MSDN article

Answer 2

You should include the correct namespace or using statement. If you don't do that, it will match System.Guid (instead of System.Runtime.InteropServices.GuidAttribute , the Attribute part is stripped out for our convenience), which indeed isn't an attribute. It's a little confusing, but true...

This code will get you there:

[System.Runtime.InteropServices.Guid("4245366B-0484-4A41-A2E8-C7D9FC3A4ED7")]