.NET FRAMEWORK 正則表達式（例子）

        private void button1_Click(object sender, EventArgs e)
        {
            string strDemo = "ABCDEFG";

            long ticks = DateTime.Now.Ticks;

            string strResult = "";

            for (int i = 0; i < 50000; i++)
            {
                strResult += strDemo;
            }

            long interval = DateTime.Now.Ticks - ticks;

            MessageBox.Show(interval.ToString() + " ticks");

        }

        private void button2_Click(object sender, EventArgs e)
        {
            string strDemo = "ABCDEFG";

            long ticks = DateTime.Now.Ticks;

            StringBuilder sb = new StringBuilder();

            for (int i = 0; i < 50000; i++)
            {
                sb.Append( strDemo);
            }

            string strResult = sb.ToString();
            long interval = DateTime.Now.Ticks - ticks;

            MessageBox.Show(interval.ToString() + " ticks");

        }

        private void button3_Click(object sender, EventArgs e)
        {
            //匹配郵政編碼
            string s1 = @"/d{6}";

            Regex rgx1 = new Regex(s1);

            if (rgx1.IsMatch(this.textBoxInput.Text))
            {
                MessageBox.Show("輸入串中包含郵政編碼。");
            }

            //匹配非負整數
            string s2 = @"^/d+$";

            Regex rgx2 = new Regex(s2);

            if (rgx2.IsMatch(this.textBoxInput.Text))
            {
                MessageBox.Show("輸入串是一個非負整數");
            }

            //匹配正整數
            string s3 = @"/+?0*[1-9]/d*";

            Regex rgx3 = new Regex(s3);

            MatchCollection matches = rgx3.Matches(this.textBoxInput.Text);     //在輸入串中搜索所有符合要求的子串

            foreach (Match mth in matches)
            {
                MessageBox.Show(mth.Value);
            }

            //匹配整數
            string s4 = @"[/+/-]?/d+";

            //匹配三位小數
            string s5 = @"[/+/-]?/d+/./d{3}";

            //匹配整數或者1-3位小數
            string s6 = @"[/+/-]?/d+(?:/./d{1,3})?";

            //匹配所有以Tom開始的單詞
            string s7 = @"Tom[a-zA-Z]*/b";

            Regex rgx7 = new Regex(s7, RegexOptions.IgnoreCase);

            matches = rgx7.Matches(this.textBoxInput.Text);

            foreach (Match mth in matches)
            {
                MessageBox.Show(mth.Value);
            }

            //匹配http url http://www.sina.com.cn:80/dir/test.html?p1=%ACDE&p2=%0235
            string s8 = @"https?/:////[/w/-_]+(/.[/w/-_]+)*(/:/d{1,5})?(//[/w/-/._]*)*(/?[/w/%/+/=/&]+)?";

        }

        private void button4_Click(object sender, EventArgs e)
        {
            string s1 = @"^/d{6}$";

            Regex rgx1 = new Regex(s1);

            if (rgx1.IsMatch(this.textBoxInput.Text))
            {
                MessageBox.Show("輸入串是一個郵政編碼。");
            }
        }

        private void button5_Click(object sender, EventArgs e)
        {
            string anchorPattern = @"/<a/s+(?:.*?)href=""(.*?)""(?:.*?)/>(.*?)/<//a/>";

            Regex rgx = new Regex(anchorPattern, RegexOptions.IgnoreCase | RegexOptions.Multiline);

            System.IO.StreamReader reader = new System.IO.StreamReader("E://163.html");
            string strContent = reader.ReadToEnd();

            reader.Close();

            MatchCollection matches = rgx.Matches(strContent);

            foreach (Match mth in matches)
            {
                ListViewItem item = new ListViewItem(mth.Value);

                string strAnchorHref = mth.Groups[1].Value;
                string strAnchorText = mth.Groups[2].Value;

                item.SubItems.Add(strAnchorText);
                item.SubItems.Add(strAnchorHref);

                this.listViewHyperLinks.Items.Add(item);
            }
        }