Documentation for this section has not yet been entered.
The value of this property is displayed as the cell ToolTip when the mouse pointer is over the cell and the property value is not string.Empty. If the value of this property is string.Empty, the cell will display a ToolTip containing the value of the cell if the value is truncated in the cell display; otherwise, the cell will not display a ToolTip. You can also prevent the display of a ToolTip by setting the DataGridView.ShowCellToolTips property to false.
When the System.Windows.Forms.DataGridView control DataGridView.DataSource property is set or its DataGridView.VirtualMode property is true, getting the value of the DataGridViewCell.ToolTipText property raises the DataGridView.CellToolTipTextNeeded event of the control and returns the value of the DataGridViewCellToolTipTextNeededEventArgs.ToolTipText property as specified in the event handler. If there are no handlers for the event, getting the value of the DataGridViewCell.ToolTipText property returns the previously specified value or its default value of string.Empty.
Handling the DataGridView.CellToolTipTextNeeded event is primarily useful when working with large amounts of data to avoid performance penalties when setting the cell DataGridViewCell.ToolTipText value for multiple cells. For more information, see Best Practices for Scaling the Windows Forms DataGridView Control.
Changing this property raises the DataGridView.CellToolTipTextChanged event on the owning System.Windows.Forms.DataGridView, if one exists.