How to Show ToolTip for RadSpreadsheet Cell

Environment

Product Version	Product	Author
2023.2.606	RadSpreadsheet for WinForms	Dinko Krastev

Description

For performance reasons, the cells in RadSpreadsheet are not separate elements and this prevents us from using the ToolTipTextNeeded event like in other controls.

Solution

To add a tooltip to a cell, we will need to subscribe to the MouseMove event of the ActiveWorksheetEditor. In the event handler, we can create our own instance of a RadToolTip and call its Show() method. Here is how you can get the cell under the mouse and show the tooltip:

private RadWorksheetEditor editor = null;

public Form1()
{
    InitializeComponent();
    this.radSpreadsheet1.SpreadsheetElement.ActiveSheetEditorChanged += SpreadsheetElement_ActiveSheetEditorChanged;
}

private void SpreadsheetElement_ActiveSheetEditorChanged(object sender, EventArgs e)
{
    if (this.editor != null)
        this.editor.MouseMove -= Editor_MouseMove;

    this.editor = this.radSpreadsheet1.ActiveWorksheetEditor;

    if (this.editor != null)
        this.editor.MouseMove += Editor_MouseMove;
}

private RadToolTip toolTip = new RadToolTip();
private string lastCellName = "";

private void Editor_MouseMove(object sender, MouseEventArgs e)
{
    var activePresenter = this.radSpreadsheet1.ActiveWorksheetEditor.ActivePresenter as NormalWorksheetEditorPresenter;

    if (activePresenter != null)
    {
        Point point = activePresenter.PointFromControl(e.Location);
        CellIndex cellIndex = activePresenter.GetCellIndexFromViewPoint(point);
        string cellName = NameConverter.ConvertCellIndexToName(cellIndex);

        if (lastCellName != cellName)
        {
            toolTip.Show(cellName, Cursor.Position);
            lastCellName = cellName;
        }

        if (cellIndex != null && cellIndex.RowIndex == 0)
        {
            toolTip.Hide();
        }           
    }
}

Private editor As RadWorksheetEditor = Nothing

Public Sub New()
    InitializeComponent()
  AddHandler  Me.radSpreadsheet1.SpreadsheetElement.ActiveSheetEditorChanged, AddressOf SpreadsheetElement_ActiveSheetEditorChanged
End Sub

Private Sub SpreadsheetElement_ActiveSheetEditorChanged(ByVal sender As Object, ByVal e As EventArgs)
    If Me.editor IsNot Nothing Then
        RemoveHandler Me.editor.MouseMove, AddressOf Editor_MouseMove
    End If

    Me.editor = Me.radSpreadsheet1.ActiveWorksheetEditor

    If Me.editor IsNot Nothing Then
       AddHandler Me.editor.MouseMove, AddressOf Editor_MouseMove
    End If
End Sub

Private toolTip As RadToolTip = New RadToolTip()
Private lastCellName As String = ""

Private Sub Editor_MouseMove(ByVal sender As Object, ByVal e As MouseEventArgs)
    Dim activePresenter = TryCast(Me.radSpreadsheet1.ActiveWorksheetEditor.ActivePresenter, NormalWorksheetEditorPresenter)

    If activePresenter IsNot Nothing Then
        Dim point As Point = activePresenter.PointFromControl(e.Location)
        Dim cellIndex As CellIndex = activePresenter.GetCellIndexFromViewPoint(point)
        Dim cellName As String = NameConverter.ConvertCellIndexToName(cellIndex)

        If lastCellName <> cellName Then
            toolTip.Show(cellName, Cursor.Position)
            lastCellName = cellName
        End If

        If cellIndex IsNot Nothing AndAlso cellIndex.RowIndex = 0 Then
            toolTip.Hide()
        End If
    End If
End Sub