本文實例講述了ASP.NET過濾HTML標簽只保留換行與空格的方法。分享給大家供大家參考。具體分析如下：
自己從網上找了一個過濾HTML標簽的方法，我也不知道誰的才是原創的，反正很多都一樣。我把那方法復制下來，代碼如下：
/// 去除HTML標記
/// </summary>
/// <param name="NoHTML">包括HTML的源碼 </param>
/// <returns>已經去除后的文字</returns>
public static string NoHTML(string Htmlstring)
{
//刪除腳本
Htmlstring = Regex.Replace(Htmlstring, @"<script[^>]*?>.*?</script>", "",
RegexOptions.IgnoreCase);
//刪除HTML
Htmlstring = Regex.Replace(Htmlstring, @"<(.[^>]*)>", "",
RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"([/r/n])[/s]+", "",
RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"-->", "", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"<!--.*", "", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(quot|#34);", "/"",
RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(amp|#38);", "&",
RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(lt|#60);", "<",
RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(gt|#62);", ">",
RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(nbsp|#160);", " ",
RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(iexcl|#161);", "/xa1",
RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(cent|#162);", "/xa2",
RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(pound|#163);", "/xa3",
RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(copy|#169);", "/xa9",
RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&#(/d+);", "",
RegexOptions.IgnoreCase);
Htmlstring.Replace("<", "");
Htmlstring.Replace(">", "");
Htmlstring.Replace("/r/n", "");
Htmlstring = HttpContext.Current.Server.HtmlEncode(Htmlstring).Trim();
return Htmlstring;
}
以上代碼是從網上直接復制過來的，這個確實能過濾掉所有的HTML標簽，但是這個不是我想要的，這個過濾得太干凈了，我如果用textarea輸入框的話，我是要保留空格跟換行的。
然后我就自己改了一下這個方法，textarea的換行是/n，所以我得把這些標簽重新匹配替換成<br>，這樣的話從數據庫中讀取到頁面時，就能正確的換行了，把空格替換成HTML的空格符，大功告成。
/// 去除HTML標記(保留br跟/r/n)
/// </summary>
/// <param name="NoHTML">包括HTML的源碼 </param>
/// <returns>已經去除后的文字</returns>
public static string NewNoHTML(string Htmlstring)
{
//Htmlstring.Replace("//r//n", "%r%n").Replace("<br>","%br%").Replace("<br/>","%br&%").Replace("//n","%n");
//刪除腳本
Htmlstring = Regex.Replace(Htmlstring, @"<script[^>]*?>.*?</script>", "",
RegexOptions.IgnoreCase);
//刪除HTML
Htmlstring = Regex.Replace(Htmlstring, @"<(.[^>]*)>", "",
RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"-->", "", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"<!--.*", "", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(quot|#34);", "/"",
RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(amp|#38);", "&",
RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(lt|#60);", "<",
RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(gt|#62);", ">",
RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(nbsp|#160);", " ",
RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(iexcl|#161);", "/xa1",
RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(cent|#162);", "/xa2",
RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(pound|#163);", "/xa3",
RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(copy|#169);", "/xa9",
RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&#(/d+);", "",
RegexOptions.IgnoreCase);
Htmlstring.Replace("<", "");
Htmlstring.Replace(">", "");
//Htmlstring.Replace("/r/n", "");
Htmlstring = HttpContext.Current.Server.HtmlEncode(Htmlstring);
Htmlstring = Regex.Replace(Htmlstring, @"((/r/n))", "<br>");
Htmlstring = Regex.Replace(Htmlstring, @"(/r|/n)", "<br>");
Htmlstring = Regex.Replace(Htmlstring, @"(/s)", " ");
return Htmlstring;
}
這個過濾可以用于讓用戶輸入發布內容時的過濾。
希望本文所述對大家的asp.net程序設計有所幫助。
