I agree that sometimes there's a solid use case to display a UserControl whether it's "three buttons" or each row having its own rolling Chart of real time data or whatever! One approach that long-term has worked for me, tried and true, is having a DataGridViewUserControlColumn class similar to the one coded below that can host a control in the cell bounds instead of just drawing one.
The theory of operation is to allow the bound data class to have properties that derive from Control. The corresponding auto-generated column(s) in the DGV can be swapped out. Then, when a DataGridViewUserControlCell gets "painted" instead of drawing the cell what happens instead is that the control is moved (if necessary) so that its bounds coincide with the cell bounds being drawn. Since the user control is in the DataGridView.Controls collection, the UC stays on top in the z-order and paints the same as any child of any container would.
The item's UserControl is added to the DataGridView.Controls collection the first time it's drawn and removed when the cell's DataGridView property is set to null (e.g. when user deletes a row). When the AllowUserToAddRows options is enabled, the "new row" list item doesn't show a control until the item editing is complete.
Typical Record class
class Record : INotifyPropertyChanged
{
public Record()
{
Modes.TextChanged += (sender, e) =>
OnPropertyChanged(nameof(Description));
Actions.Click += (sender, e) =>
{ _ = execTask(); };
}
public string Description
{
get => $"{Modes.Text} : {_description}";
set
{
if (!Equals(_description, value))
{
_description = value;
OnPropertyChanged();
}
}
}
string _description = string.Empty;
#region B O U N D C O N T R O L S o f A N Y T Y P E
public ButtonCell3Up Modes { get; } = new ButtonCell3Up();
public ProgressBar Actions { get; } = new ProgressBar { Value = 1 };
#endregion B O U N D C O N T R O L S o f A N Y T Y P E
private async Task execTask()
{
Actions.Value = 0;
while(Actions.Value < Actions.Maximum)
{
await Task.Delay(250);
Actions.Value++;
}
}
private void onModesTextChanged(object sender, EventArgs e) =>
OnPropertyChanged(nameof(Description));
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged([CallerMemberName] string? propertyName = null)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
}
Configure DGV
public partial class MainForm : Form
{
public MainForm() => InitializeComponent();
protected override void OnLoad(EventArgs e)
{
base.OnLoad(e);
// Add 15 items
for (int i = 0; i < 5; i++)
{
Records.Add(new Record { Description = "Voltage Range" });
Records.Add(new Record { Description = "Current Range" });
Records.Add(new Record { Description = "Power Range" });
}
for (int i = 1; i <= Records.Count; i++)
Records[i - 1].Modes.Labels = new[] { $"{i}A", $"{i}B", $"{i}C", };
dataGridView.RowTemplate.Height = 50;
dataGridView.DataSource = Records;
dataGridView.MouseDoubleClick += onMouseDoubleClick;
#region F O R M A T C O L U M N S
dataGridView.Columns[nameof(Record.Description)].AutoSizeMode = DataGridViewAutoSizeColumnMode.Fill;
dataGridView.Columns[nameof(Record.Modes)].Width = 200;
DataGridViewUserControlColumn.Swap(dataGridView.Columns[nameof(Record.Modes)]);
dataGridView.Columns[nameof(Record.Actions)].Width = 200;
dataGridView.Columns[nameof(Record.Actions)].DefaultCellStyle.Padding = new Padding(5);
DataGridViewUserControlColumn.Swap(dataGridView.Columns[nameof(Record.Actions)]);
Debug.Assert(
dataGridView.Controls.OfType<ButtonCell3Up>().Count().Equals(0),
"Expecting the Clear method to reset the custom controls");
#endregion F O R M A T C O L U M N S
}
}
Custom Cell with Paint override
public class DataGridViewUserControlCell : DataGridViewCell
{
private Control _control = null;
private DataGridViewUserControlColumn _column;
public override Type FormattedValueType => typeof(string);
private DataGridView _dataGridView = null;
protected override void OnDataGridViewChanged()
{
base.OnDataGridViewChanged();
if((DataGridView == null) && (_dataGridView != null))
{
// WILL occur on Swap() and when a row is deleted.
if (TryGetControl(out var control))
{
_column.RemoveUC(control);
}
}
_dataGridView = DataGridView;
}
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)
{
using (var brush = new SolidBrush(getBackColor(@default: Color.Azure)))
{
graphics.FillRectangle(brush, cellBounds);
}
if (DataGridView.Rows[rowIndex].IsNewRow)
{ /* G T K */
}
else
{
if (TryGetControl(out var control))
{
SetLocationAndSize(cellBounds, control);
}
}
Color getBackColor(Color @default)
{
if((_column != null) && (_column.DefaultCellStyle != null))
{
Style = _column.DefaultCellStyle;
}
return Style.BackColor.A == 0 ? @default : Style.BackColor;
}
}
public void SetLocationAndSize(Rectangle cellBounds, Control control, bool visible = true)
{
control.Location = new Point(
cellBounds.Location.X +
Style.Padding.Left,
cellBounds.Location.Y + Style.Padding.Top);
control.Size = new Size(
cellBounds.Size.Width - (Style.Padding.Left + Style.Padding.Right),
cellBounds.Height - (Style.Padding.Top + Style.Padding.Bottom));
control.Visible = visible;
}
public bool TryGetControl(out Control control)
{
control = null;
if (_control == null)
{
try
{
if ((RowIndex != -1) && (RowIndex < DataGridView.Rows.Count))
{
var row = DataGridView.Rows[RowIndex];
_column = (DataGridViewUserControlColumn)DataGridView.Columns[ColumnIndex];
var record = row.DataBoundItem;
var type = record.GetType();
var pi = type.GetProperty(_column.Name);
control = (Control)pi.GetValue(record);
if (control.Parent == null)
{
DataGridView.Controls.Add(control);
_column.AddUC(control);
}
}
}
catch (Exception ex) {
Debug.Assert(false, ex.Message);
}
_control = control;
}
else control = _control;
return _control != null;
}
}
Custom Column
public class DataGridViewUserControlColumn : DataGridViewColumn
{
public DataGridViewUserControlColumn() => CellTemplate = new DataGridViewUserControlCell();
public static void Swap(DataGridViewColumn old)
{
var dataGridView = old.DataGridView;
var indexB4 = old.Index;
dataGridView.Columns.RemoveAt(indexB4);
dataGridView.Columns.Insert(indexB4, new DataGridViewUserControlColumn
{
Name = old.Name,
AutoSizeMode = old.AutoSizeMode,
Width = old.Width,
DefaultCellStyle = old.DefaultCellStyle,
});
}
protected override void OnDataGridViewChanged()
{
base.OnDataGridViewChanged();
if ((DataGridView == null) && (_dataGridView != null))
{
_dataGridView.Invalidated -= (sender, e) => refresh();
_dataGridView.Scroll -= (sender, e) => refresh();
_dataGridView.SizeChanged -= (sender, e) => refresh();
foreach (var control in _controls.ToArray())
{
RemoveUC(control);
}
}
else
{
DataGridView.Invalidated += (sender, e) =>refresh();
DataGridView.Scroll += (sender, e) =>refresh();
DataGridView.SizeChanged += (sender, e) =>refresh();
}
_dataGridView = DataGridView;
}
// Keep track of controls added by this instance
// so that they can be removed by this instance.
private readonly List<Control> _controls = new List<Control>();
internal void AddUC(Control control)
{
_controls.Add(control);
DataGridView.Controls.Add(control);
}
internal void RemoveUC(Control control)
{
_controls.Remove(control);
if (_dataGridView != null)
{
_dataGridView.Controls.Remove(control);
}
}
int _wdtCount = 0;
private void refresh()
{
var capture = ++_wdtCount;
// Allow changes to settle.
Task
.Delay(TimeSpan.FromMilliseconds(10))
.GetAwaiter()
.OnCompleted(() =>
{
if (DataGridView != null)
{
foreach (var row in DataGridView.Rows.Cast<DataGridViewRow>().ToArray())
{
if (row.Cells[Index] is DataGridViewUserControlCell cell)
{
if (row.IsNewRow)
{ /* G T K */
}
else
{
var cellBounds = DataGridView.GetCellDisplayRectangle(cell.ColumnIndex, cell.RowIndex, true);
if (cell.TryGetControl(out var control))
{
cell.SetLocationAndSize(cellBounds, control, visible: !row.IsNewRow);
}
}
}
}
}
});
}
private DataGridView _dataGridView = null;
}