Public Function AddTable(ByVal dt_base As DataTable, _
        ByVal dt_add As DataTable) As Boolean
 
        'Parameter checken
        If dt_base Is Nothing Or dt_add Is Nothing Then Return False
        If Not dt_base.Rows.Count = dt_add.Rows.Count Then Return False
 
        For c As Integer = 0 To dt_add.Columns.Count - 1
            If dt_base.Columns.Contains _
              (dt_add.Columns(c).ColumnName) Then Return False
        Next c
 
        Dim cc As Integer = dt_base.Columns.Count
 
        'Spalten anhängen
        For c As Integer = 0 To dt_add.Columns.Count - 1
            dt_base.Columns.Add(CloneColumn(dt_add.Columns(c)))
        Next c
 
        'Zeilen füllen
        For r As Integer = 0 To dt_base.Rows.Count - 1
            For c As Integer = 0 To dt_add.Columns.Count - 1
                dt_base.Rows(r)(cc + c) = dt_add(r)(c)
            Next c
        Next r
 
        Return True
    End Function
 
    Private Function CloneColumn(ByVal dc As DataColumn) As DataColumn
 
        Dim dn As New DataColumn
        With dn
            .ColumnName = dc.ColumnName
            .DataType = dc.DataType
            .Unique = dc.Unique
            .DefaultValue = dc.DefaultValue
            .AllowDBNull = dc.AllowDBNull
        End With
        Return dn
 
    End Function