正则小问题，求解！

Question

string=" <p class=\"topiccontent\">　....，于是找了一家补胎店给看了看。<br><br><img src=\"/uploads/app/pic/s_20110625055343396094.JPG\" alt=\"\"><br>补胎店给看了后，说好解决<br><img src=\"/uploads/app/pic/s_20110625055343395211.JPG\" alt=\"\">　.....</p>"
  现在想通过Ｃ#正则实现２个功能：１，将上面的图片标签通过正则替换成形如：<a href="/uploads/app/pic/s_20110625055343396094.JPG"><img src="/uploads/app/pic/s_20110625055343396094.JPG" alt="" width="300px"></a>。这样做的目的希望文章中点击小图是浮动弹出大图。
２，将所有图片变成１中所示。求解正则和替换详细内容，谢谢各位老师

Answer 1

不知道是不是这个意思：
string s = "<p class=\"topiccontent\">　....，于是找了一家补胎店给看了看。<br><br><img src=\"/uploads/app/pic/s_20110625055343396094.JPG\" alt=\"\"><br>补胎店给看了后，说好解决<br><img src=\"/uploads/app/pic/s_20110625055343395211.JPG\" alt=\"\">　.....</p>";
string r = Regex.Replace(s, @"<img src=""([^>""]+?)"" alt="""">", @"<a href=""$1""><img src=""$1"" alt="" width=""300px""></a>");
Response.Write(Server.HtmlEncode(r));

Answer 2

        string str = @"<p class=""topiccontent"">　....，于是找了一家补胎店给看了看。<br><br>
           <img src=""/uploads/app/pic/s_20110625055343396094.JPG"" alt=""""><br>补胎店给看了后，说好解决<br><img src=""/uploads/app/pic/s_20110625055343395211.JPG"" alt="""">　.....</p>";
        string result = Regex.Replace(str, @"<img[^>]*?src=(['""\s]?)([^'""\s]+)\1[^>]*?>", "<a href=\"$2\">$0</a>");
        Response.Write(result);
/*
<p class="topiccontent">　....，于是找了一家补胎店给看了看。<br><br>
           <a href="/uploads/app/pic/s_20110625055343396094.JPG"><img src="/uploads/app/pic/s_20110625055343396094.JPG" alt=""></a><br>补胎店给看了后，说好解决<br><a href="/uploads/app/pic/s_20110625055343395211.JPG"><img src="/uploads/app/pic/s_20110625055343395211.JPG" alt=""></a>　.....</p>
*/

Answer 3

这样：
string s = "<p class=\"topiccontent\">　....，于是找了一家补胎店给看了看。<br><br><img src=\"/uploads/app/pic/s_20110625055343396094.JPG\" alt=\"\"><br>补胎店给看了后，说好解决<br><img src=\"/uploads/app/pic/s_20110625055343395211.JPG\" alt=\"\">　.....</p>";
string r = Regex.Replace(s, @"(?<=<p class=""topiccontent"">.+?)<img src=""([^>""]+?)"" alt="""">(?=.+?</p>)", @"<a href=""$1""><img src=""$1"" alt="" width=""300px""></a>");
Response.Write(Server.HtmlEncode(r));

Answer 4

没注意看还有个限制大小。
        string str = @"<p class=""topiccontent"">　....，于是找了一家补胎店给看了看。<br><br>
           <img src=""/uploads/app/pic/s_20110625055343396094.JPG"" alt=""""><br>补胎店给看了后，说好解决<br><img src=""/uploads/app/pic/s_20110625055343395211.JPG"" alt="""">　.....</p>";
        string result = Regex.Replace(str, @"<img[^>]*?src=(['""\s]?)([^'""\s]+)\1[^>]*?>", "<a href=\"$2\"><img src=\"$2\" alt=\"\" width=\"300px\" /></a>");
        Response.Write(result);
/*
<p class="topiccontent">　....，于是找了一家补胎店给看了看。<br><br>
           <a href="/uploads/app/pic/s_20110625055343396094.JPG"><img src="/uploads/app/pic/s_20110625055343396094.JPG" alt="" width="300px" /></a><br>补胎店给看了后，说好解决<br><a href="/uploads/app/pic/s_20110625055343395211.JPG"><img src="/uploads/app/pic/s_20110625055343395211.JPG" alt="" width="300px" /></a>　.....</p>
*/

Answer 5

string s = "<p class=\"topiccontent\">　....，于是找了一家补胎店给看了看。<br><br><img src=\"/uploads/app/pic/s_20110625055343396094.JPG\" alt=\"\"><br>补胎店给看了后，说好解决<br><img src=\"/uploads/app/pic/s_20110625055343395211.JPG\" alt=\"\">　.....</p>";
string r = Regex.Replace(s, @"(?<=<p class=""topiccontent"">.+?)<img src=""([^>""]+?)"" alt="""">(?=.+?</p>)", @"<a href=""$1""><img src=""$1"" alt="""" width=""300px""></a>");
Response.Write(Server.HtmlEncode(r));
输出：
<p class="topiccontent">　....，于是找了一家补胎店给看了看。<br><br><a href="/uploads/app/pic/s_20110625055343396094.JPG"><img src="/uploads/app/pic/s_20110625055343396094.JPG" alt="" width="300px"></a><br>补胎店给看了后，说好解决<br><a href="/uploads/app/pic/s_20110625055343395211.JPG"><img src="/uploads/app/pic/s_20110625055343395211.JPG" alt="" width="300px"></a>　.....</p>
哈哈～～

Answer 6

下面的，你看看对不对string str="<p class=\"topiccontent\">　....，于是找了一家补胎店给看了看。"+
               "<br><br><img src=\"/uploads/app/pic/s_20110625055343396094.JPG\" alt=\"\"><br>补胎店给看了后，说好解决<br><img src=\"/uploads/app/pic/s_20110625055343395211.JPG\" alt=\"\">　.....</p>";
           
           Regex regex = new Regex(@"(?<=(<\w+\s+[^>]+>))");
           MatchCollection mc=regex.Matches(str);
           foreach (Match v in mc)
               Console.WriteLine(v.Groups[1]);输出结果是这样的：
"<p class=\"topiccontent\">
<img src=\"/uploads/app/pic/s_20110625055343396094.JPG\" alt=\"\">
<img src=\"/uploads/app/pic/s_20110625055343395211.JPG\" alt=\"\">

Answer 7

刚才验证了４楼，有个问题：其中alt的内容应该要继承（不应该为空）。希望再修改下。谢谢！

Answer 8

        string str = @"<p class=""topiccontent"">　....，于是找了一家补胎店给看了看。<br><br>
           <img src=""/uploads/app/pic/s_20110625055343396094.JPG"" alt=""aa""><br>补胎店给看了后，说好解决<br><img src=""/uploads/app/pic/s_20110625055343395211.JPG"" alt=""bb"">　.....</p>";
        string result = Regex.Replace(str, @"<img[^>]*?src=(['""\s]?)([^'""\s]+)\1[^>]*?alt=(['""\s]?)([^'""\s]+)\3[^>]*?>", "<a href=\"$2\"><img src=\"$2\" alt=\"$4\" width=\"300px\" /></a>");
        Response.Write(result);
/*
<p class="topiccontent">　....，于是找了一家补胎店给看了看。<br><br>
           <a href="/uploads/app/pic/s_20110625055343396094.JPG"><img src="/uploads/app/pic/s_20110625055343396094.JPG" alt="aa" width="300px" /></a><br>补胎店给看了后，说好解决<br><a href="/uploads/app/pic/s_20110625055343395211.JPG"><img src="/uploads/app/pic/s_20110625055343395211.JPG" alt="bb" width="300px" /></a>　.....</p>
*/

Answer 9

string s = "<p class=\"topiccontent\">　....，于是找了一家补胎店给看了看。<br><br><img src=\"/uploads/app/pic/s_20110625055343396094.JPG\" alt=\"333\"><br>补胎店给看了后，说好解决<br><img src=\"/uploads/app/pic/s_20110625055343395211.JPG\" alt=\"abc\">　.....</p>";
        string r = Regex.Replace(s, @"(?<=<p class=""topiccontent"">.+?)<img src=""([^>""]+?)"" alt=""([^""]*?)"">(?=.+?</p>)", @"<a href=""$1""><img src=""$1"" alt=""$2"" width=""300px""></a>");
        Response.Write(Server.HtmlEncode(r));

Answer 10

            string strContent = context;
          //  strContent = Regex.Replace(strContent, @"<img src=""([^>""]+?)"" alt=""([^""]*?)"">", @"<a href=""$1""><img alt=""$2"" src=""$1"" width=""550px""></a>", RegexOptions.IgnoreCase);　一，　无法匹配替换
          //  strContent = Regex.Replace(strContent, @"<img[^>]*?src=(['""\s]?)([^'""\s]+)\1[^>]*?alt=(['""\s]?)([^'""\s]+)\3[^>]*?>", "<a href=\"$2\"><img src=\"$2\" alt=\"$4\" width=\"550px\" /></a>", RegexOptions.IgnoreCase);　二，　无法匹配替换
            strContent = Regex.Replace(strContent, @"<img[^>]*?src=(['""\s]?)([^'""\s]+)\1[^>]*?>", "<a href=\"$2\"><img src=\"$2\" alt=\"\" width=\"300px\" /></a>", RegexOptions.IgnoreCase);　　三，可以
            return strContent;
感谢。用４楼的即上面三的正则可以正确匹配替换。但用一和二都无法匹配，请问什么原因。

Answer 11

一，二和三的差别在一个alt,有可能你要匹配的图片有的没有alt。

Answer 12

这样试试            string str = @"<p class=""topiccontent"">　....，于是找了一家补胎店给看了看。<br><br>
           <img src=""/uploads/app/pic/s_20110625055343396094.JPG""><br>补胎店给看了后，说好解决<br><img src=""/uploads/app/pic/s_20110625055343395211.JPG"" alt=""bb"">　.....</p>";
            string result = Regex.Replace(str, @"<img[^>]*?src=(['""\s]?)([^'""\s]+)\1[^>]*?(?:alt=(['""\s]?)([^'""\s]+)\3[^>]*?)?>", "<a href=\"$2\"><img src=\"$2\" alt=\"$4\" width=\"300px\" /></a>");

Answer 13

感谢各位。
huangwenquan123　最后的办法解决了问题，分理应多些。