Public Class Form1
    'Create empty string of 8 numbers
    Dim number(6) As String 'This needs to be (7) but causes an endless loop when changed

    Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        ReadingRandomMutuallyExclusiveArray(number, 8) 'Number of members
    End Sub

    Sub ReadingRandomMutuallyExclusiveArray(ByRef arraytorandomize, ByVal MaxNumber)


        Dim a As String
        Dim arrayused() As String
        Dim i As Integer
        Dim ArrayIndexUsed As Integer


        Randomize()
        ' ReDim Preserve arrayused(7)

        arrayused = Split(GeneratedNumberString(MaxNumber), ",")


        '-----------------------------------------------------------------------------------------------------

        For i = LBound(arraytorandomize) To UBound(arraytorandomize)

            Do
                ArrayIndexUsed = Int(Rnd() * (MaxNumber - 1) + 1) 'ArrayIndexUsed = Random Number Picked

                'DoEvent
            Loop While arrayused(ArrayIndexUsed) < 1

            arrayused(ArrayIndexUsed) = 0 'This sets picked out array value as zero

            arraytorandomize(i) = ArrayIndexUsed 'Massiv is second array

            a = Join(number, ",")  'number is picked out of arrayused and create new list of 8

            TextBox1.Text = a & vbCrLf

        Next i
        Exit Sub

    End Sub

    Function GeneratedNumberString(ByVal RemainingNumberstoRandomize) 'Creates 8,7,6,5,4,3,2,1
        If RemainingNumberstoRandomize > 0 Then GeneratedNumberString = RemainingNumberstoRandomize _
        & "," & GeneratedNumberString(RemainingNumberstoRandomize - 1)
        If RemainingNumberstoRandomize = 1 Then RemainingNumberstoRandomize = 0

    End Function

    Private Sub btnGo_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnGo.Click
        ReadingRandomMutuallyExclusiveArray(number, 8)
    End Sub
End Class

Dim intArray(7) As Integer ' Our random array of integers.
Dim rndInst As New Random() ' Our random instance.

' Loop through all elements in the integer array.
For i As Integer = 0 To 7
    ' Create a GoTo point when it creats a random number
    ' that isn't mutually exclusive.
GoAgain:
    ' Give the array number a value so we can check it
    intArray(i) = rndInst.Next(0, 8) + 1
    
    ' Check if there are any other arrays with the
    ' newly created random value.
    For j As Integer = 0 To 7
        ' Ignore the array that we just assigned a value to.
        If j = i Then Continue For
        
        ' If not mutually exclusive, this will be true.
        If intArray(i) = intArray(j) Then GoTo GoAgain
    Next
    
    ' A number has been born! :D
Next

' Our Resulting String
Dim stringResult As String = ""

' Loop through all elements of the intArray
For i As Integer = 0 To 7
    ' If it's not the last one we will put
    ' a comma on the end, just to make it
    ' look snazzy :)
    If Not i = 7 Then : stringResult += Convert.ToString(intArray(i)) & ","
    Else : stringResult += Convert.ToString(intArray(i))
    End If
Next

' Show a message box displaying the resulting string.
MessageBox.Show(stringResult)

Function GetNumberString(ByVal listSize As Integer) As String
    Dim seedArray(listSize) As Integer
    Dim rndArray(listSize) As Integer
    Dim rndInst As New Random()
    Dim rndPos As Integer
    Dim lastPos As Integer

    For i As Integer = 0 To listSize - 1
        seedArray(i) = i + 1
    Next

    For i As Integer = 0 To listSize - 2
        lastPos = (listSize - 1) - i
        rndPos = rndInst.Next(0, lastPos)
        rndArray(i) = seedArray(rndPos)
        seedArray(rndPos) = seedArray(listSize-i)
    Next
    rndArray(listSize - 1) = seedArray(0)

    Dim txtOut As String = ""
    For i As Integer = 0 To listSize - 1
        If Not i = 0 Then
            txtOut += ", "
        End If
        txtOut += Convert.ToString(rndArray(i))
    Next
    
    Return txtOut
End Function

TextBox1.Text = GetNumberString(8)