DataGridView单元格设置日期格式

private void dataGridView1_CellFormatting(object sender, DataGridViewCellFormattingEventArgs e) 
        { 
            if (e.ColumnIndex == dataGridView1.Columns["StartTime"].Index || e.ColumnIndex == dataGridView1.Columns["EndTime"].Index) 
            { 
                if (dpString.dTrim(e.Value) != "") 
                { 
                    e.Value = Convert.ToDateTime(e.Value).ToString("MM/dd/yyyy - HH:mm:ss"); 
                } 
            } 
        }