Getting values from TestCategories using TestCategoryAttribute

In the code given below:

Assembly _assembly = Assembly.LoadFile(AssembleyPath);
                    Type[] types = _assembly.GetExportedTypes();
                    foreach (Type type in types)
                    {
                        Attribute _classAttribute = type.GetCustomAttribute(typeof(TestClassAttribute));
                        if (_classAttribute != null)
                        {
                            TreeNode _n = new TreeNode();
                            _n.Text = type.Name;
                            if (type.Name.ToLower().Contains("testbase"))
                                // For exculding test base class from tree node list
                                continue;
                            MemberInfo[] members =
                                type.GetMembers(BindingFlags.Public | BindingFlags.Instance | BindingFlags.InvokeMethod | BindingFlags.Default);
                            foreach (MemberInfo member in members)
                            {

                                Attribute _att = member.GetCustomAttribute(typeof(TestMethodAttribute));
                                if (_att != null)
                                {
                                    var _t = type.GetMethod(member.Name);
                                    var testCategories = _t.GetCustomAttributes(typeof(TestCategoryAttribute));

                                }

                            }

                        }
                    }

I want to extract test category value which i can see while i debug in the Quickwatch window by expanding the elements but when i try to access it using the dot operator i'm unable to access it.

when i hover my mouse on testCategories (last line of the code), i see {Microsoft.VisualStudio.TestTools.UnitTesting.TestCategoryAttribute[3]} On further expanding the arrary say at index 0 i see TestCategories and TypeId. On expanding TestCategories i see the value i want to use but when i try to access in the code, i'm only able to access TypeId. I'm unable to access TestCategories. Is there any way by which i can access it? I tried accessing it using lambda expression like this: testCategories.Any(c => c == "xyz")

but it doesn't yield anything.