Imports System
Imports System.Reflection
Imports System.Collections

Module HashCodeVB

    ' Visual Basic requires that the AttributeUsage be specified. 
    ' A custom attribute to allow two authors per method.
    <AttributeUsage(AttributeTargets.All.Method)> _
    Public Class AuthorsAttribute
        Inherits Attribute

        Public Sub New(ByVal name1 As String, ByVal name2 As String)
            myAuthorName1 = name1
            myAuthorName2 = name2
        End Sub 

        Protected myAuthorName1 As String 
        Protected myAuthorName2 As String 

        Public Property AuthorName1() As String 
            Get 
                Return myAuthorName1
            End Get 
            Set(ByVal Value As String)
                myAuthorName1 = AuthorName1
            End Set 
        End Property 

        Public Property AuthorName2() As String 
            Get 
                Return myAuthorName2
            End Get 
            Set(ByVal Value As String)
                myAuthorName2 = AuthorName2
            End Set 
        End Property 

        ' Use the hash code of the string objects and Xor them together. 
        Public Overrides Function GetHashCode() As Integer 
            Return myAuthorName1.GetHashCode() Xor myAuthorName2.GetHashCode()
        End Function 

    End Class 

    ' Provide the author names for each method of the class. 
    Public Class TestClass
        <Authors("Immanuel Kant", "Lao Tzu")> _
        Public Sub Method1()
        End Sub

        <Authors("Jean-Paul Sartre", "Friedrich Nietzsche")> _
        Public Sub Method2()
        End Sub

        <Authors("Immanuel Kant", "Lao Tzu")> _
        Public Sub Method3()
        End Sub

        <Authors("Jean-Paul Sartre", "Friedrich Nietzsche")> _
        Public Sub Method4()
        End Sub

        <Authors("Immanuel Kant", "Friedrich Nietzsche")> _
        Public Sub Method5()
        End Sub 
    End Class 

    Sub Main()
        ' Get the class type to access its metadata. 
        Dim clsType As Type = GetType(TestClass)
        ' Use a hash table to store the hash codes and methods. 
        Dim hTable As Hashtable = New Hashtable()
        Dim mInfo As MethodInfo
        ' Iterate through all the methods of the class. 
        For Each mInfo In clsType.GetMethods()
            ' Get the unique hash code for these authors. 
            Dim attr As Attribute = Attribute.GetCustomAttribute(mInfo, GetType(AuthorsAttribute))
            If Not attr Is Nothing Then 
                Dim authAttr As AuthorsAttribute = CType(attr, _
                    AuthorsAttribute)
                Dim hCode As Integer = authAttr.GetHashCode()
                ' See if it's already been added to the hash table. 
                If hTable.Contains(hCode) Then 
                    Dim o As Object = hTable(hCode)
                    If TypeOf o Is ArrayList Then 
                        ' If so, retrieve the array using the Item syntax. 
                        Dim al As ArrayList = CType(o, ArrayList)
                        ' Add the method to the array list.
                        al.Add(mInfo.Name)
                        ' Put the edited array list back into the table.
                        hTable(hCode) = al
                    End If 
                ' This is the first occurrence of this hash code. 
                Else 
                    ' Create a new array list. 
                    Dim al As ArrayList = New ArrayList()
                    ' Add the method name as the first entry.
                    al.Add(mInfo.Name)
                    ' Add the new hash code and array list to the table.
                    hTable.Add(hCode, al)
                End If 
            End If 
        Next 

        ' Get the hash table's enumerator and iterate through the table. 
        Dim dictEnum As IDictionaryEnumerator = hTable.GetEnumerator
        While dictEnum.MoveNext()
            ' Get the array list for this iteration. 
            Dim o As Object = dictEnum.Value
            If TypeOf o Is ArrayList Then 
                Dim al As ArrayList = CType(o, ArrayList)
                Dim i As Integer 
                ' Access each element of the array.
                for i = 0 to al.Count - 1
                    ' For the first element, retrieve the author names. 
                    If i = 0 Then 
                        Dim methodName as Object = al(i)
                        ' Get the metadata for the method. 
                        Dim mInfo2 As MethodInfo = _
                            clsType.GetMethod(CType(methodName, String))
                        ' Retrieve the Authors attribute again. 
                        Dim attr As Attribute = Attribute.GetCustomAttribute( _
                            mInfo2, GetType(AuthorsAttribute))
                        If Not attr Is Nothing And _
                            TypeOf attr Is AuthorsAttribute Then 
                            ' Convert the attribute to access its data. 
                            Dim authAttr As AuthorsAttribute = _
                                CType(attr, AuthorsAttribute)
                            ' Display the author's names.
                            Console.WriteLine("Authors: {0}, {1}", _
                                authattr.AuthorName1, authattr.AuthorName2)
                        Else
                            Console.WriteLine("The authors could not " + _
                                "be retrieved.")
                        End If 
                    End If 
                    ' Display each method authored by this team.
                    Console.WriteLine(al(i))
                Next i
                Console.WriteLine("")
            End If 
        End While 
    End Sub 
End Module

using System;
using System.Reflection;
using System.Collections;

namespace HashCodeCS 
{
    // A custom attribute to allow two authors per method. 
    public class AuthorsAttribute : Attribute 
    {
        public AuthorsAttribute(string name1, string name2) 
        {
            authorName1 = name1;
            authorName2 = name2;
        }

        protected string authorName1;
        protected string authorName2;
	
        public string AuthorName1 
        {
            get { return authorName1; }
            set { authorName1 = AuthorName1; }
        }

        public string AuthorName2 
        {
            get { return authorName2; }
            set { authorName2 = AuthorName2; }
        }

        // Use the hash code of the string objects and xor them together. 
        public override int GetHashCode() 
        {
            return authorName1.GetHashCode() ^ authorName2.GetHashCode();
        }
    }

    // Provide the author names for each method of the class. 
    public class TestClass 
    {
        [Authors("Immanuel Kant", "Lao Tzu")]
        public void Method1()
        {}

        [Authors("Jean-Paul Sartre", "Friedrich Nietzsche")]
        public void Method2()
        {}

        [Authors("Immanuel Kant", "Lao Tzu")]
        public void Method3()
        {}

        [Authors("Jean-Paul Sartre", "Friedrich Nietzsche")]
        public void Method4()
        {}

        [Authors("Immanuel Kant", "Friedrich Nietzsche")]
        public void Method5()
        {}
    }

    class DemoClass 
    {
        static void Main(string[] args) 
        {
            // Get the class type to access its metadata.
            Type clsType = typeof(TestClass);

            // Use a hash table to store the hash codes and methods.
            Hashtable hTable = new Hashtable();

            // Iterate through all the methods of the class. 
            foreach(MethodInfo mInfo in clsType.GetMethods()) 
            {
                // Get the Authors attribute for the method if it exists.
                AuthorsAttribute authAttr = 
                    (AuthorsAttribute)Attribute.GetCustomAttribute(
                    mInfo, typeof(AuthorsAttribute));
                if (authAttr != null) 
                {
                    // Get the unique hash code for these authors. 
                    int hCode = authAttr.GetHashCode();

                    // See if it's already been added to the hash table. 
                    if (hTable.Contains(hCode)) 
                    {
                        // If so, retrieve the array using the Item syntax.
                        ArrayList al = (ArrayList)hTable[hCode];
                        // Add the method to the array list.
                        al.Add(mInfo.Name);
                        // Put the edited array list back into the table.
                        hTable[hCode] = al;
                    }

                        // This is the first occurrence of this hash code. 
                    else 
                    {
                        // Create a new array list.
                        ArrayList al = new ArrayList();
                        // Add the method name as the first entry.
                        al.Add(mInfo.Name);
                        // Add the new hash code and array list to the table.
                        hTable.Add(hCode, al);
                    }
                }
            }

            // Get the hash table's enumerator and iterate through the table.
            IDictionaryEnumerator dictEnum = hTable.GetEnumerator();
            while (dictEnum.MoveNext()) 
            {
                // Get the array list for this iteration.
                ArrayList al = (ArrayList)dictEnum.Value;
                // Access each element of the array. 
                for (int i=0; i<al.Count; i++) 
                {
                    // For the first element, retrieve the author names. 
                    if (i == 0) 
                    {
                        // Get the metadata for the method.
                        MethodInfo mInfo = clsType.GetMethod((String)al[i]);
                        // Retrieve the Authors attribute again.
                        AuthorsAttribute authAttr = 
                            (AuthorsAttribute)Attribute.GetCustomAttribute(
                            mInfo, typeof(AuthorsAttribute));
                        // Display the authors names. 
                        if (authAttr != null)
                            Console.WriteLine("Authors: {0}, {1}", 
                                authAttr.AuthorName1, authAttr.AuthorName2);
                        else
                            Console.WriteLine("The authors could not be retrieved.");
                    }
                    // Display each method authored by this team.
                    Console.WriteLine(al[i]);
                }
                Console.WriteLine("");
            }
        }
    }
}