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截取固定长度的复杂字符串

2018年01月23日 ⁄ 综合 ⁄ 共 4347字 ⁄ 字号 评论关闭

public static string GetContentSummary(string content, int length, bool StripHTML) {
           
if (string.IsNullOrEmpty(content) || length == 0)
               
return "";
           
if (StripHTML) {
                Regex re
= new Regex("<[^>]*>");
                content
= re.Replace(content, "");
                content
= content.Replace(" ", "").Replace(" ", "");
                content
= content.Replace("/r/n", " ");
               
if (content.Length <= length)
                   
return content;
               
else
                   
return content.Substring(0, length) + "……";
            }
           
else {
               
if (content.Length <= length)
                   
return content;

                int pos = 0, npos = 0, size = 0;
               
bool firststop = false, notr = false, noli = false;
                StringBuilder sb
= new StringBuilder();
               
while (true) {
                   
if (pos >= content.Length)
break;
                   
string cur = content.Substring(pos, 1);
                   
if (cur == "<") {
                       
string next = content.Substring(pos + 1, 3).ToLower();
                       
if (next.IndexOf("p") == 0 && next.IndexOf("pre") != 0) {
                            npos
= content.IndexOf(">", pos) + 1;
                        }
                       
else if (next.IndexOf("/p") == 0 && next.IndexOf("/pr") != 0) {
                            npos
= content.IndexOf(">", pos) + 1;
                           
if (size < length)
                                sb.Append(
"<br/>");
}
else if (next.IndexOf("br") == 0) {
                            npos
= content.IndexOf(">", pos) + 1;
                           
if (size < length)
                                sb.Append(
"<br/>");
                        }
                       
else if (next.IndexOf("img") == 0) {
                            npos
= content.IndexOf(">", pos) + 1;
                           
if (size < length) {
                                sb.Append(content.Substring(pos, npos
- pos));
                                size
+= npos - pos + 1;
}
}
else if (next.IndexOf("li") == 0 || next.IndexOf("/li") == 0) {
                            npos
= content.IndexOf(">", pos) + 1;
                           
if (size < length) {
                                sb.Append(content.Substring(pos, npos
- pos));
                            }
                           
else {
                               
if (!noli && next.IndexOf("/li") == 0) {
                                    sb.Append(content.Substring(pos, npos
- pos));
                                    noli
= true;
                                }
                            }
                        }
                       
else if (next.IndexOf("tr") == 0 || next.IndexOf("/tr") == 0) {
                            npos
= content.IndexOf(">", pos) + 1;
                           
if (size < length) {
                                sb.Append(content.Substring(pos, npos
- pos));
                            }
                           
else {
                               
if (!notr && next.IndexOf("/tr") == 0) {
                                    sb.Append(content.Substring(pos, npos
- pos));
                                    notr
= true;
                                }
                            }
                        }
                       
else if (next.IndexOf("td") == 0 || next.IndexOf("/td") == 0) {
                            npos
= content.IndexOf(">", pos) + 1;
                           
if (size < length) {
                                sb.Append(content.Substring(pos, npos
- pos));
                            }
                           
else {
                               
if (!notr) {
                                    sb.Append(content.Substring(pos, npos
- pos));
                                }
                            }
                        }
                       
else {
                            npos
= content.IndexOf(">", pos) + 1;
                            sb.Append(content.Substring(pos, npos
- pos));
                        }
                       
if (npos <= pos)
                            npos
= pos + 1;
                        pos
= npos;
                    }
                   
else {
                       
if (size < length) {
                            sb.Append(cur);
                            size
++;
                        }
                       
else {
                           
if (!firststop) {
                                sb.Append(
"……");
                                firststop
= true;
                            }
                        }
                        pos
++;
                    }

                }
                return sb.ToString();
            }
        }

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