ReadOnly MAX As Integer = 99
Select(Function(Value As Integer)
   Return If(Value < MAX, Value, Rand.Next(0, MAX))
End Function))

 
    ' Get Numbers Not In Range.
    ' ( By Elektro )
    '
    ' Usage Examples:
    '
    ' MsgBox(String.Join(", ", GetNumbersNotInRange({1, 3, 5, 7, 9}, 0, 10).ToArray)) ' Result: 0, 2, 4, 6, 8, 10
    '
    ''' <summary>
    ''' Given a numeric collection, gets all the numbers which are not in a specified range.
    ''' </summary>
    ''' <param name="NumbersInRange">Indicates the numbers collection which are in range.</param>
    ''' <param name="MinRange">Indicates the minimum range.</param>
    ''' <param name="MaxRange">Indicates the maximum range.</param>
    ''' <returns>System.Collections.Generic.IEnumerable(Of System.Int32).</returns>
    Private Function GetNumbersNotInRange(ByVal NumbersInRange As IEnumerable(Of Integer),
                                          ByVal MinRange As Integer,
                                          ByVal MaxRange As Integer) As IEnumerable(Of Integer)
 
        Return From Number As Integer
               In Enumerable.Range(MinRange, MaxRange + 1)
               Where Not NumbersInRange.Contains(Number)
 
    End Function

    Private Sub Test(sender As Object, e As EventArgs) Handles MyBase.Shown
 
        Dim NumbersInRange As Integer() = {2, 4, 6, 8, 9}
 
        Dim NumbersNotInRange As Integer() = GetNumbersNotInRange(NumbersInRange, 0, 10).ToArray
 
        MsgBox(String.Join(", ", NumbersNotInRange)) ' Result: 0, 1, 3, 5, 7, 10
 
    End Sub

Public Class Form1
 
    Dim XMax As Short = 99
    Dim Xmin As Short = 0
    Dim x As Integer = 0
    Dim Número As Double
    Private TextBoxes As TextBox() = {Nothing}
    Private Result1 As Int32(), Result2 As Int32(), Result3 As Int32()
    Private _textBox As Object
    Private _getNumbersNotInRange As Object
 
    Private Property ListBox1Count As Integer
    ReadOnly MAX As Integer = 99
    Private Property Calcular As Object
 
    Private Property TextBox(ByVal TextBoxCount As Short) As Object
        Get
            Return _textBox
        End Get
        Set(ByVal value As Object)
            _textBox = value
        End Set
    End Property
 
 
    ReadOnly Property Num1 As Int32
        Get
            Return CInt(TextBox1.Text)
        End Get
    End Property
 
    ReadOnly Property Num2 As Int32
        Get
            Return CInt(TextBox2.Text)
        End Get
    End Property
    ReadOnly Property Num3 As Int32
        Get
            Return CInt(TextBox3.Text)
        End Get
    End Property
 
    Private Property GetNumbersNotInRange(ByVal Result11 As IEnumerable(Of Integer), ByVal Xmin As Integer, ByVal XMax As Integer) As Object
        Get
            Return _getNumbersNotInRange
        End Get
        Set(ByVal value As Object)
            _getNumbersNotInRange = value
        End Set
    End Property
 
 
    Private Sub Sumar(ByVal sender As Object, ByVal e As EventArgs) Handles Button1.Click
 
 
 
        Result1 = {Num1 + 10, Num1 + 20, Num1 + 30} _
                  .Distinct().ToArray ' Elimino duplicados
 
        Result2 = {Num2 + 10, Num2 + 20, Num2 + 30} _
                  .Distinct().ToArray ' Elimino duplicados
 
        Result3 = {Num3 + 10, Num3 + 20, Num3 + 30} _
                  .Distinct().ToArray ' Elimino duplicados
 
 
        ' primero concatenas y eliminas duplicados en el primer array:
        Dim Result11 As IEnumerable(Of Integer) =
              (Result1.Concat(Result3).Concat(Result3).
              Distinct).ToArray
 
        ' luego instancias un segundo array que obtiene los números que no están dentro del rango 'Xmin'-'Xmax' del primer array:
        Dim NumbersNotInRange As Integer() =
             GetNumbersNotInRange(Result11, Xmin, XMax).ToArray
 
        ' Y por último reemplazas los números que no están en el rango, en el primer array:
       Result11 =Result11.Select(Function(Value As Integer)
                              ReadOnly If(Value < MAX, Value, Rand.Next(0, MAX))
                   End Function))
 
 
        ' y los añades a los listbox:
        ListBox1.Items.AddRange(Result11.Cast(Of Object).ToArray)
        ListBox2.Items.AddRange(NumbersNotInRange.Cast(Of Object).ToArray)
 
 
    End Sub
 
 
End Class