Multiple Selection in Datagridcomboboxcolumn

Question

I need a DataGridComboBoxColumn which should allow multiple selection. To do this, I created a DataGridComboBoxColumn populated with CheckBoxes. I handle the Checkbox selection through CommandManager.PreviewExecuted event selecting the check boxes based on stored strings separated by ';' My code:

            if (((DataGrid)sender).CurrentCell.Column.DisplayIndex == 6)
            {
                DataGridRow row = (DataGridRow)SupplierProductsGrid.ItemContainerGenerator.ContainerFromIndex(SupplierProductsGrid.SelectedIndex);
                DataGridCell RowColumn = SupplierProductsGrid.Columns[6].GetCellContent(row).Parent as DataGridCell;
                ComboBox cb = RowColumn.Content as ComboBox;
                if (cb != null)
                {
                    Debug.WriteLine("Entered Combobox editing");
                    ComboBoxFill(cb, true);
                }
            }

and in CellEditEnding event I create a string based on the checked box items and store that back to table. My code for that is:

        DataGridRow row = (DataGridRow)SupplierProductsGrid.ItemContainerGenerator.ContainerFromIndex(SupplierProductsGrid.SelectedIndex);
        DataGridCell RowColumn = SupplierProductsGrid.Columns[6].GetCellContent(row).Parent as DataGridCell;
        ComboBox cb = RowColumn.Content as ComboBox;
        if (cb != null)
        {
            //Debug.WriteLine("Entered Combobox Consolidation");
            ComboBoxFill(cb, false);
            return;
        }

The code for checking the comboBox CheckBox items from string and collating the checked items back to string is handled by ComboBoxFill method which works fine. No issue there. I am able to save to the table and retrieve the values. However unless the user select the combobox there is no way user knows what has been selected. I have a previous DataGridTextColumn which provides feedback. I would like to have both the DataGridTextColumn and DataGridComboBoxColumn in one column or a better approach to use multiple select DataGridComboBoxColumn My Partial XAML looks like this. Of interest is MaterialType Text column and MaterialType combo column. I need to have this under one column so it will be more user friendly.

<DataGridTextColumn Binding="{Binding SupplierLeadTime}" Header="Lead Time" Width="1*" />
<DataGridComboBoxColumn x:Name="StorageUnitCombo"  Header="Package Unit"  SelectedValuePath="StorageUnitId" Width="2.5*" 
     DisplayMemberPath="Description" SelectedItemBinding="{Binding BaseStorageUnitNavigation}" />
<DataGridTextColumn x:Name="Materialtype" Header="Material Type" Width="140" Binding="{Binding MaterialType}" Visibility="Visible" ElementStyle="{StaticResource WT}" IsReadOnly="True"/>
<DataGridComboBoxColumn x:Name="MTCombo" Header="Material Type Combo" Width="140" ItemsSource="{Binding Source={StaticResource MaterialTypeViewSource}}" />

Any Help will be greatly appreciated.

user2330192 · Answer 1 · 2021-12-24T15:43:31.080

After more Google Search and more Browsing of codes, most solutions were not to my requirement nor were that applicable to my solution. However I manage to get the gist of many codes and put together a simple solution that works like a charm. The solution is in the ComboBox Text field. By setting the value for this field, I am able to produce the result that I wanted - Displaying multi selected ComboBox. Here is the XAML code:

                <DataGridComboBoxColumn x:Name="MTCombo" Header="Material Type Combo" Width="2.5*" 
                                        ItemsSource="{Binding Source={StaticResource MaterialTypeViewSource}}" >
                    <DataGridComboBoxColumn.ElementStyle>
                        <Style TargetType="{x:Type ComboBox}">
                            <Setter Property ="Template">
                                <Setter.Value>
                                    <ControlTemplate>
                                        <TextBlock Text="{Binding MaterialType}" Style="{StaticResource WTR}" 
                                             PreviewTextInput="TextBlock_PreviewTextInput" MouseDown="TextBlock_MouseDown"  />
                                    </ControlTemplate>
                                </Setter.Value>
                            </Setter>
                        </Style>
                    </DataGridComboBoxColumn.ElementStyle>
                    <DataGridComboBoxColumn.EditingElementStyle>
                        <Style TargetType="ComboBox">
                            <Setter Property="IsDropDownOpen" Value="True" />
                            <Setter Property="Text" Value="Select Material Types"/>
                            <Setter Property="IsReadOnly" Value="True"/>
                            <Setter Property="IsEditable" Value="True"/>
                        </Style>
                    </DataGridComboBoxColumn.EditingElementStyle>
                </DataGridComboBoxColumn>

Now Only thing was to connect the Text Preview Input & Mouse event to open up the Combobox. That is easily achieved by triggering the BeginEdit method. Here is the code for that:

private void TextBlock_MouseDown(object sender, MouseButtonEventArgs e)
{
    SupplierProductsGrid.BeginEdit();
}

The images speaks for themselves. Check the figure for Material Type combo, which displays all the selected elements separated by ;. Hope this helps others looking for such a feature

Multiple Selection in Datagridcomboboxcolumn

1 Answers1