Private Function Category_output(year As Integer) As DataTable
        Dim dt As DataTable = ArchivDB.Kontodetails
        Dim cal As Globalization.Calendar = _
          Globalization.CultureInfo.CurrentCulture.Calendar
 
        Dim q = From row As DataRow In dt
          Let Ausgaben = row.Field(Of Double)("Betrag")
          Let Kategorie = row.Field(Of String)("Kategorieausgabe")
          Let ID = row.Field(Of Integer)("KategorieausgabeID")
        Where year = row.Field(Of Date)("Buchungsdatum").Year _
        AndAlso ID > 0
        Group By Kat = Kategorie Into Sum(Ausgaben), Count()
 
        '--------Ende deklarieren
        Dim df As New DataTable
        With df.Columns
            .Add("Kategorie", GetType(String))
            .Add("Anzahl", GetType(Integer))
            .Add("Ausgaben", GetType(Double))
        End With
 
        For Each el In q
            df.Rows.Add(el.Kat, el.Count, el.Sum)
        Next el
 
 
 
        DataGridView1.DataSource = df
        With ChartKategorie
            .Series.Clear()
            .Series.Add("default")
            .Series("default").ChartType = _
              DataVisualization.Charting.SeriesChartType.Pie
            .DataSource = df
            .Series("default").XValueMember = "Kategorie"
            .Series("default").YValueMembers = "Anzahl"
        End With
 
        Return df
    End Function