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this.cbbKategorie.SelectedItem.ToString()					

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((DerTyp) this.cbbKategorie.SelectedItem).ID					

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            // 
            // cbbKategorie
            // 
            this.cbbKategorie.DataBindings.Add(new System.Windows.Forms.Binding("SelectedValue", this.kategorieBindingSource, "kategorie_id", true));
            this.cbbKategorie.DataSource = this.kategorieBindingSource;
            this.cbbKategorie.DisplayMember = "kategorie_name";
            this.cbbKategorie.FormattingEnabled = true;
            this.cbbKategorie.Location = new System.Drawing.Point(91, 48);
            this.cbbKategorie.Name = "cbbKategorie";
            this.cbbKategorie.Size = new System.Drawing.Size(121, 21);
            this.cbbKategorie.TabIndex = 2;
            this.cbbKategorie.ValueMember = "kategorie_id";					

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  if comboBox1.SelectedItem <> nil then
  begin
    var drv := DataRowView(comboBox1.SelectedItem);
    MessageBox.Show(drv['ID'].ToString);
  end;					

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  if comboBox1.SelectedItem <> nil then
  begin
    var drv := DataRowView(comboBox1.SelectedItem);
    var row := websiteDataSet.CategoryRow(drv.Row);
    MessageBox.Show(row.ID.ToString);
  end;