reverse engineering obfuscated .net dll

Question

I am decompiling a third party .NET dll which was obfuscated using codeveil
my aim is to get full source code,

I tried decompiling using dnSpy, JustDecompile & Reflector
however it just shows the public methods and properties inside the dll
and no method body is shown

something like this:

    public class TestManager
    {
        // Fields
        private OleDbDatabase b;

        // Methods
        public TestManager();
        public OperationResult AddRecord(XProfile record);
        public OperationResult RevokeRecord(XProfile record);
    }

it errors out when I try to export source code

so how do I get the source code? is it possible?
I guess at-least if I see the IL code then I can rewrite the functions