Question

I am dynamically adding a DataGridViewCheckBoxColumn to my DataGridView.

However, I can’t seem to add the tooltip to the checkboxes:

// Method to Populate the DataGrid
    private void PopulateDataGrid(objPatient patient)
    {
        this.uiDocumentDataGrid.DataSource = DataManager.GetDocumentData(patient);
        // Hide unnecessary columns
        this.uiDocumentDataGrid.Columns["Forename"].Visible = false;
        this.uiDocumentDataGrid.Columns["Surname"].Visible = false;

        // Add column for selection
        DataGridViewCheckBoxColumn selectedColumn = new DataGridViewCheckBoxColumn();
        selectedColumn.Name = "Selected";
        selectedColumn.HeaderText = "Attach";
        selectedColumn.ReadOnly = false;
        this.uiDocumentDataGrid.Columns.Insert(0,selectedColumn);

        // Set columns except checkbox to readonly
        foreach(DataGridViewColumn c in this.uiDocumentDataGrid.Columns)
        {
            if (c.Index > 0)
            {
                c.ReadOnly = true;
            }
        }

        // Refresh the view in case of draw issues
        this.uiDocumentDataGrid.Refresh();

        // Add tooltip to each checkbox
        foreach (DataGridViewRow r in uiDocumentDataGrid.Rows)
        {
            r.Cells["Selected"].ToolTipText = "Check this box to select this document.";
        }

        // Disable the functionality button if no rows.
        if (this.uiDocumentDataGrid.RowCount == 0)
        {
            this.uiSendButton.Enabled = false;
        }

    }

No tooltip shows with this method. Am I missing something obvious?

Answer 1

Don’t try setting the ToolTip value of cells in the constructor of the form. Try setting them in the Load or Shown events instead:

protected override void OnLoad(EventArgs e) {
  foreach (DataGridViewRow r in uiDocumentDataGrid.Rows)
  {
    r.Cells["Selected"].ToolTipText = "Check this box to select this document.";
  } 
  base.OnLoad(e);
}