C# - Prüfen, ob Teil des .NET Frameworks

using System;
using System.Collections.Generic;

public static class DotNetTools
{
    /// <summary>
    /// Checks if a type is part of the Microsoft .NET framework
    /// </summary>
    /// <param name="type">Type</param>
    /// <returns>Is part of the .NET framework (true) or not (false)</returns>
    public static bool IsDotNetType(Type type)
    {
        if (null == type)
        {
            throw new ArgumentNullException("type");
        }

        // prepare list of known .NET-Assemblies
        List<Assembly> asms = new List<Assembly>();
        // System
        asms.Add(Assembly.GetAssembly(typeof(object)));
        // System.Data
        asms.Add(Assembly.GetAssembly(typeof(System.Data.IDbConnection)));
        // System.Drawing
        asms.Add(Assembly.GetAssembly(typeof(System.Drawing.Size)));
        // System.Text.RegularExpressions                
        asms.Add(Assembly.GetAssembly(typeof(System.Text.RegularExpressions.Regex)));
        // System.Web
        asms.Add(Assembly.GetAssembly(typeof(System.Web.HttpUtility)));
        // System.Windows.Forms
        asms.Add(Assembly.GetAssembly(typeof(System.Windows.Forms.Control)));
        // System.Xml
        asms.Add(Assembly.GetAssembly(typeof(System.Xml.XmlNode)));
        // System.Xml.Linq (.NET 3.0)
        asms.Add(Assembly.GetAssembly(typeof(System.Xml.Linq.XObject)));

        bool isDotNet = false;

        // search list
        foreach (Assembly asm in asms)
        {
            if (asm.GetType(type.FullName, false, false) is Type)
            {
                // Names are OK => check if same assemblies
                isDotNet = asm.Equals(type.Assembly);

                if (isDotNet)
                {
                    break;
                }
                // Assemblies are not the same
            }
        }

        return isDotNet;
    }
}