private void dataGridView1_CellFormatting(object sender, DataGridViewCellFormattingEventArgs e)
        {
            try
            {
                if (e.ColumnIndex == 1)        //控制要格式化的列
                {
                    float val = Convert.ToSingle(e.Value);
                    string valStr = val.ToString("P");

                    e.Value = valStr;                    //替换格式化值
                    e.FormattingApplied = true;
                }
            }
            catch (System.Exception ex)
            {
                e.FormattingApplied = false;
            }
        }