C# – How to select a complete dataGridView Row when the user clicks a cell of that row

I figured out a better way of doing this, using the CellFormatting event:

Private Sub uxContacts_CellFormatting(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellFormattingEventArgs) Handles uxContacts.CellFormatting
    If uxContacts.CurrentCell IsNot Nothing Then
        If e.RowIndex = uxContacts.CurrentCell.RowIndex And e.ColumnIndex = uxContacts.CurrentCell.ColumnIndex Then
            e.CellStyle.SelectionBackColor = Color.SteelBlue
        Else
            e.CellStyle.SelectionBackColor = uxContacts.DefaultCellStyle.SelectionBackColor
        End If
    End If
End Sub

This trick works for me:

    grd.DataSource = DT;

    // Set your desired AutoSize Mode:
    grd.Columns[0].AutoSizeMode = DataGridViewAutoSizeColumnMode.AllCells;
    grd.Columns[1].AutoSizeMode = DataGridViewAutoSizeColumnMode.AllCells;
    grd.Columns[2].AutoSizeMode = DataGridViewAutoSizeColumnMode.Fill;

    // Now that DataGridView has calculated it's Widths; we can now store each column Width values.
    for (int i = 0; i <= grd.Columns.Count - 1; i++)
    {
        // Store Auto Sized Widths:
        int colw = grd.Columns[i].Width;

        // Remove AutoSizing:
        grd.Columns[i].AutoSizeMode = DataGridViewAutoSizeColumnMode.None;

        // Set Width to calculated AutoSize value:
        grd.Columns[i].Width = colw;
    }

In the Code above: You set the Columns AutoSize Property to whathever AutoSizeMode you need. Then (Column by Column) you store each column Width value (from AutoSize value); Disable the AutoSize Property and finally, set the Column Width to the Width value you previously stored.