Friend Function SqlDatenHolen(Of T As {New, IDisposable, IDbConnection})(ByVal _
  sQuery As String) As DataTable
    Dim dt As New DataSet
    Dim oCommand As Common.DbDataAdapter
 
    Using conn As New T()
        conn.ConnectionString = ConStr
 
        Try
            conn.Open()
 
            Select Case GetType(T).Name
                Case GetType(SqlClient.SqlConnection).Name
                    oCommand = New SqlClient.SqlDataAdapter(sQuery, TryCast( _
                      conn, SqlClient.SqlConnection))
                Case GetType(OleDb.OleDbConnection).Name
                    oCommand = New OleDb.OleDbDataAdapter(sQuery, TryCast(conn, _
                      OleDb.OleDbConnection))
                Case GetType(Odbc.OdbcConnection).Name
                    oCommand = New Odbc.OdbcDataAdapter(sQuery, TryCast(conn, _
                      Odbc.OdbcConnection))
            End Select
 
            oCommand.Fill(dt)
        Catch ex As Exception
            MsgBox("Datenbankzugriff auf SQL-Server fehlgeschlagen.", True)
        Finally
            conn.Close()
        End Try
    End Using
 
    Return dt.Tables(0)
End Function