c#从html中获取图片地址

 
using System.Text.RegularExpressions;
string ohtml = this.TextBox1.Text;
            System.Text.RegularExpressions.MatchCollection m;
            //提取字符串的图片
            m = Regex.Matches(ohtml, "(<img).*?>");
            for (int i = 0; i < m.Count; i++)
            {
                string ostr = m[i].ToString();
                //提取图片的地址
                System.Text.RegularExpressions.MatchCollection m2;
                m2 = Regex.Matches(ostr, "(src=)['|\"].*?['\"]");
                for (int j = 0; j < m2.Count; j++)
                {
                    string strTemp = m2[j].ToString();
                    strTemp = strTemp.Replace("src=", "");
                    strTemp = strTemp.Replace("\"", "");
                    strTemp = strTemp.Replace("'", "");