add custom DataGridViewColumn with label and button per cell

Question

I want to add a custom DataGridViewColumn to my DataGridView. This column should create the following cell per row

At first I created a custom UserControl that creates a label with a button.

    private class AllocationControl : UserControl
    {
        public AllocationControl(IndexField[] indexFields, BatchField[] batchFields)
        {
            Label lbl = new Label();
            Controls.Add(lbl);

            ContextMenuStrip contextMenu = new ContextMenuStrip();
            // fill the menu
            Controls.Add(contextMenu);

            Button btn = new Button();
            btn.Click += (object sender, EventArgs e) =>
            {
                contextMenu.Show(Cursor.Position);
            };
            Controls.Add(btn);
        }

        public string DisplayedName { get; private set; }
        public double SelectedID { get; private set; }
    }

I have to pass in some data as constructor parameters but this is not relevant for the question.

After that I create a custom DataGridViewCell

    private class DataGridViewAllocationCell : DataGridViewCell
    {
        public DataGridViewAllocationCell()
        {
        }

        protected override void Paint(Graphics graphics, Rectangle clipBounds, Rectangle cellBounds, int rowIndex, DataGridViewElementStates cellState, object value, object formattedValue, string errorText, DataGridViewCellStyle cellStyle, DataGridViewAdvancedBorderStyle advancedBorderStyle, DataGridViewPaintParts paintParts)
        {
            AllocationControl allocationControl = value as AllocationControl;
            Bitmap allocationControlImage = new Bitmap(cellBounds.Width, cellBounds.Height);
            allocationControl.DrawToBitmap(allocationControlImage, new Rectangle(0, 0, allocationControl.Width, allocationControl.Height));
            graphics.DrawImage(allocationControlImage, cellBounds.Location);
        }
    }

This cell should keep the custom control and display it.

At the end I add this cell to my custom DataGridViewColumn by setting the CellTemplate

    private class DataGridViewAllocationColumn : DataGridViewColumn
    {
        public DataGridViewAllocationColumn()
        {
            CellTemplate = new DataGridViewAllocationCell();
        }
    }

My question is how can I assign the UserControl to the DataGridViewCell?

I took this guide

https://docs.microsoft.com/en-us/dotnet/framework/winforms/controls/how-to-host-controls-in-windows-forms-datagridview-cells

but they all show up how to create a single control and put it into a cell. I have to setup three controls (label, button and contextMenu) within one cell.

Answer 1

There are 3 main pillars for a new column type:

• DataGridViewColumn is responsible for properties which you set in design mode in column editor of the control.
• DataGridViewCell is responsible for appearance of the cell. It renders the value and other painting parts in cell and initialize the editing control (if the column has any editing control).
• DataGridViewEditingControl is responsible for editing the value of the cell.

When creating a new column you can derive from DataGridViewColumn or one of its derived classes. Also when creating a new cell for the column, you can derive from DataGridViewCell or one of its derived classes. Also when creating a new editing control, you can derive from one of the existing editing controls, or you can start by deriving from a control class and implementing IDataGridViewEditingControl interface.

Keep in mind, the editing control will be shown just in the editing cell. Rest of cells show what you render in the paint method of the cell.

Example

Here in this post, I've shared an example of drawing a custom cell containing a label and a button. I've not created an editing control because for this example, we can derive from DataGridViewButtonColumn and DataGridViewButtonCell without needing to create an editing control. We just add some properties to column and change paint logic and override OnContentClick to show the context menu, like this:

The custom column has LabelText and ButtonText properties. When you click on the button part, it shows the ContextMenuStrip which you assigned to corresponding property.

Note: This is just an example and depending on the requirements, you may want to change properties, rendering logic and the way that you show menu or anything else. But I think it's a good start point.

Here is the code:

using System.Drawing;
using System.Windows.Forms;
public class DataGridViewAllocationControlColumn : DataGridViewButtonColumn
{
    public DataGridViewAllocationControlColumn()
    {
        this.CellTemplate = new DataGridViewAllocationControlCell();
    }
    public string LabelText { get; set; }
    public string ButtonText { get; set; }
    public override object Clone()
    {
        var c = (DataGridViewAllocationControlColumn)base.Clone();
        c.LabelText = this.LabelText;
        c.ButtonText = this.ButtonText;
        return c;
    }
}
public class DataGridViewAllocationControlCell : DataGridViewButtonCell
{
    protected override void Paint(Graphics graphics, Rectangle clipBounds,
        Rectangle cellBounds, int rowIndex, 
        DataGridViewElementStates elementState,
        object value, object formattedValue, string errorText,
        DataGridViewCellStyle cellStyle,
        DataGridViewAdvancedBorderStyle advancedBorderStyle,
        DataGridViewPaintParts paintParts)
    {
        var g = this.DataGridView;
        var c = (DataGridViewAllocationControlColumn)this.OwningColumn;
        base.Paint(graphics, clipBounds, cellBounds, rowIndex, elementState,
            value, formattedValue, errorText, cellStyle, advancedBorderStyle,
            DataGridViewPaintParts.All &
            ~DataGridViewPaintParts.ContentBackground &
            ~DataGridViewPaintParts.ContentForeground);
        var r1 = g.GetCellDisplayRectangle(c.Index, rowIndex, false);
        var r2 = GetContentBounds(rowIndex);
        var r3 = new Rectangle(r1.Location, new Size(GetLabelWidth(), r1.Height));
        r2.Offset(r1.Location);
        base.Paint(graphics, clipBounds, r2, rowIndex, elementState,
            value, c.ButtonText, errorText, cellStyle, advancedBorderStyle,
            DataGridViewPaintParts.All);
        TextRenderer.DrawText(graphics, c.LabelText, cellStyle.Font,
            r3, cellStyle.ForeColor);
    }
    protected override Rectangle GetContentBounds(Graphics graphics, 
        DataGridViewCellStyle cellStyle, int rowIndex)
    {
        var w = GetLabelWidth();
        var r = base.GetContentBounds(graphics, cellStyle, rowIndex);
        return new Rectangle(r.Left + w, r.Top, r.Width - w, r.Height);
    }
    protected override void OnContentClick(DataGridViewCellEventArgs e)
    {
        base.OnContentClick(e);
        var g = this.DataGridView;
        var c = (DataGridViewAllocationControlColumn)this.OwningColumn;
        var r1 = GetContentBounds(e.RowIndex);
        var r2 = g.GetCellDisplayRectangle(e.ColumnIndex, e.RowIndex, false);
        var p = new Point(r2.Left + r1.Left, r2.Top + r1.Bottom);
        if (c.ContextMenuStrip != null)
            c.ContextMenuStrip.Show(g, p);
    }
    private int GetLabelWidth()
    {
        var c = (DataGridViewAllocationControlColumn)this.OwningColumn;
        var text = c.LabelText;
        return TextRenderer.MeasureText(text, c.DefaultCellStyle.Font).Width;
    }
}