How to create DropDown DataGrid column in WinForms DataGrid (SfDataGrid)?

About the sample

This example illustrates how to create DropDown DataGrid column in WinForms DataGrid.

WinForms DataGrid (SfDataGrid) allows you to show another SfDataGrid in a dropdown of a column by creating a custom column using ComboDropDown control as edit element.

public Form1()
{
    InitializeComponent();

    sfDataGrid.CellRenderers.Add("DropDownDataGrid", new GridDropDownDataGridCellRenderer(this.sfDataGrid));

    sfDataGrid.Columns.Add(new GridDropDownDataGridColumn() { MappingName = "ShipCityID", HeaderText = "Ship City", DataSource = new CountryInfoRepository().Cities });
}

public class GridDropDownDataGridColumn : GridColumn
{

    public GridDropDownDataGridColumn()
    {
        SetCellType("DropDownDataGrid");
    }

    public IEnumerable DataSource { get; set; }
}

public class GridDropDownDataGridCellRenderer : GridVirtualizingCellRendererBase<ComboDropDown>
{
    SfDataGrid DataGrid { get; set; }
    public GridDropDownDataGridCellRenderer(SfDataGrid dataGrid)
    {
        DataGrid = dataGrid;
    }
    protected override void OnRender(Graphics paint, Rectangle cellRect, string cellValue, CellStyleInfo style, DataColumnBase column, RowColumnIndex rowColumnIndex)
    {
        base.OnRender(paint, cellRect, cellValue, style, column, rowColumnIndex);
    }

    

    protected override void OnInitializeEditElement(DataColumnBase column, RowColumnIndex rowColumnIndex, ComboDropDown uiElement)
    {
        Rectangle editorRectangle = GetEditorUIElementBounds();
        uiElement.Size = editorRectangle.Size;
        uiElement.Location = editorRectangle.Location;
        uiElement.DropDownWidth = 300;

        SfDataGrid dropDownDataGrid = new SfDataGrid()
        {
            DataSource = (column.GridColumn as GridDropDownDataGridColumn).DataSource,
        };

        uiElement.PopupControl = dropDownDataGrid;
        uiElement.DropDownStyle = ComboBoxStyle.DropDownList;

        this.TableControl.Controls.Add(uiElement);
        uiElement.Focus();

        base.OnInitializeEditElement(column, rowColumnIndex, uiElement);

        dropDownDataGrid.SelectionChanged += DropDownDataGrid_SelectionChanged;


    }

    private void DropDownDataGrid_SelectionChanged(object sender, SelectionChangedEventArgs e)
    {
        this.DataGrid.View.GetPropertyAccessProvider().SetValue(this.DataGrid.SelectedItem, this.DataGrid.CurrentCell.Column.MappingName, (e.AddedItems[0] as ShipCityDetails).ShipCityID);
        (this.DataGrid.CurrentCell.CellRenderer.CurrentCellRendererElement as ComboDropDown).Text = (e.AddedItems[0] as ShipCityDetails).ShipCityID.ToString();
        (this.DataGrid.CurrentCell.CellRenderer.CurrentCellRendererElement as ComboDropDown).DroppedDown = false;
    }
}

Requirements to run the demo

Visual Studio 2015 and above versions.