c#怎么設置一個字符串中某個字符的顏色

this.lblText.Style["color"] = "#777;font-size:12px";
lblText.Text = "錄入完成，總共有<b style=\"color:red\">" + CSVHelper.CountSum + "</b>條，錄入成功<b style=\"color:red\">" + CSVHelper.ThreadSum + "</b>條";