Custom Assembly Attributes

64
votes

I would like to know if I can define custom assembly attributes. Existing attributes are defined in the following way:

[assembly: AssemblyTitle("MyApplication")]  
[assembly: AssemblyDescription("This application is a sample application.")]  
[assembly: AssemblyCopyright("Copyright © MyCompany 2009")]

Is there a way I can do the following:

[assembly: MyCustomAssemblyAttribute("Hello World! This is a custom attribute.")]
2
c#.netassembliesattributes
For anyone curious, AssemblyTitle etc is located in assemblyattributes.cs. Here's the source: referencesource.microsoft.com/#mscorlib/system/reflection/…. - mekb

2 Answers

89
votes

Yes you can. We do this kind of thing.

[AttributeUsage(AttributeTargets.Assembly)]
public class MyCustomAttribute : Attribute {
    string someText;
    public MyCustomAttribute() : this(string.Empty) {}
    public MyCustomAttribute(string txt) { someText = txt; }
    ...
}

To read use this kind of linq stmt.

var attributes = assembly
    .GetCustomAttributes(typeof(MyCustomAttribute), false)
    .Cast<MyCustomAttribute>();
8
votes

Yes, use AttributeTargets.Assembly:

[AttributeUsage(AttributeTargets.Assembly)]
public class AssemblyAttribute : Attribute { ... }