C#省略号(以完整词结尾) [英] Ellipsis with C# (ending on a full word)

问题描述

我正在尝试在Umbraco中实现省略号，要求是介绍性文字的15个字符，但始终以完整的单词结尾.

I'm trying to implement ellipsis in Umbraco, the requirement being 15 characters of intro text but always ending on a full word.

我考虑过使用XSLT，但是后来意识到我可以使用一种用C#编写的简单扩展方法.

I thought of using XSLT, but then realised that I can use a simple extension method written in C# instead.

我可以轻松地为文本加上子串并附加"..."，但是遇到了必须用完整的单词结尾的问题..这是到目前为止的代码(非常复杂的:p)

I can easily substring the text and append "..." but am stuck with the issue of having to end it with a full word.. Here's my code so far (very complicated :p)

public string Ellipsis(string text, int length)
{
    return text.Substring(0, length) + "...";
}

示例文本

Lorem ipsum dolor坐在amet，amet consectetur熟练的精英人士.

Lorem ipsum dolor sit amet, amet consectetur adipiscing elit.

如果我们在上面实现了省略号方法(长度= 15)，则输出看起来像

Lorem ipsum dolor坐在amet，amet consectetur adipi ...

Lorem ipsum dolor sit amet, amet consectetur adipi...

我想确保没有单词被切成薄片，所以输出应该看起来像

Lorem ipsum dolor坐在amet，amet保密...

Lorem ipsum dolor sit amet, amet consectetur adipiscing...

任何帮助表示赞赏.

编辑

运行下面的代码示例后，如果省略号长度在最后一个单词上结束，则根本不会显示任何文本.

After running the sample for the code below, it appears that if the ellipsis length ends on the last word, no text is displayed at all.

以下是输出，请参见第56-60行

0 : Lorem...
1 : Lorem...
2 : Lorem...
3 : Lorem...
4 : Lorem...
5 : Lorem...
6 : Lorem ipsum...
7 : Lorem ipsum...
8 : Lorem ipsum...
9 : Lorem ipsum...
10 : Lorem ipsum...
11 : Lorem ipsum...
12 : Lorem ipsum dolor...
13 : Lorem ipsum dolor...
14 : Lorem ipsum dolor...
15 : Lorem ipsum dolor...
16 : Lorem ipsum dolor...
17 : Lorem ipsum dolor...
18 : Lorem ipsum dolor sit...
19 : Lorem ipsum dolor sit...
20 : Lorem ipsum dolor sit...
21 : Lorem ipsum dolor sit...
22 : Lorem ipsum dolor sit amet,...
23 : Lorem ipsum dolor sit amet,...
24 : Lorem ipsum dolor sit amet,...
25 : Lorem ipsum dolor sit amet,...
26 : Lorem ipsum dolor sit amet,...
27 : Lorem ipsum dolor sit amet,...
28 : Lorem ipsum dolor sit amet, amet...
29 : Lorem ipsum dolor sit amet, amet...
30 : Lorem ipsum dolor sit amet, amet...
31 : Lorem ipsum dolor sit amet, amet...
32 : Lorem ipsum dolor sit amet, amet...
33 : Lorem ipsum dolor sit amet, amet consectetur...
34 : Lorem ipsum dolor sit amet, amet consectetur...
35 : Lorem ipsum dolor sit amet, amet consectetur...
36 : Lorem ipsum dolor sit amet, amet consectetur...
37 : Lorem ipsum dolor sit amet, amet consectetur...
38 : Lorem ipsum dolor sit amet, amet consectetur...
39 : Lorem ipsum dolor sit amet, amet consectetur...
40 : Lorem ipsum dolor sit amet, amet consectetur...
41 : Lorem ipsum dolor sit amet, amet consectetur...
42 : Lorem ipsum dolor sit amet, amet consectetur...
43 : Lorem ipsum dolor sit amet, amet consectetur...
44 : Lorem ipsum dolor sit amet, amet consectetur...
45 : Lorem ipsum dolor sit amet, amet consectetur adipiscing...
46 : Lorem ipsum dolor sit amet, amet consectetur adipiscing...
47 : Lorem ipsum dolor sit amet, amet consectetur adipiscing...
48 : Lorem ipsum dolor sit amet, amet consectetur adipiscing...
49 : Lorem ipsum dolor sit amet, amet consectetur adipiscing...
50 : Lorem ipsum dolor sit amet, amet consectetur adipiscing...
51 : Lorem ipsum dolor sit amet, amet consectetur adipiscing...
52 : Lorem ipsum dolor sit amet, amet consectetur adipiscing...
53 : Lorem ipsum dolor sit amet, amet consectetur adipiscing...
54 : Lorem ipsum dolor sit amet, amet consectetur adipiscing...
55 : Lorem ipsum dolor sit amet, amet consectetur adipiscing...
56 : ...
57 : ...
58 : ...
59 : ...
60 : ...
61 : Lorem ipsum dolor sit amet, amet consectetur adipiscing elit.
62 : Lorem ipsum dolor sit amet, amet consectetur adipiscing elit.
63 : Lorem ipsum dolor sit amet, amet consectetur adipiscing elit.
64 : Lorem ipsum dolor sit amet, amet consectetur adipiscing elit.
65 : Lorem ipsum dolor sit amet, amet consectetur adipiscing elit.
66 : Lorem ipsum dolor sit amet, amet consectetur adipiscing elit.
67 : Lorem ipsum dolor sit amet, amet consectetur adipiscing elit.
68 : Lorem ipsum dolor sit amet, amet consectetur adipiscing elit.
69 : Lorem ipsum dolor sit amet, amet consectetur adipiscing elit.
70 : Lorem ipsum dolor sit amet, amet consectetur adipiscing elit.
71 : Lorem ipsum dolor sit amet, amet consectetur adipiscing elit.
72 : Lorem ipsum dolor sit amet, amet consectetur adipiscing elit.
73 : Lorem ipsum dolor sit amet, amet consectetur adipiscing elit.
74 : Lorem ipsum dolor sit amet, amet consectetur adipiscing elit.
75 : Lorem ipsum dolor sit amet, amet consectetur adipiscing elit.
76 : Lorem ipsum dolor sit amet, amet consectetur adipiscing elit.
77 : Lorem ipsum dolor sit amet, amet consectetur adipiscing elit.
78 : Lorem ipsum dolor sit amet, amet consectetur adipiscing elit.
79 : Lorem ipsum dolor sit amet, amet consectetur adipiscing elit.

Marko

推荐答案

if (text.Length <= length) return text;
int pos = text.IndexOf(" ", length) ;
if (pos >= 0)
    return text.Substring(0, pos) + "...";
return text;

这是我用以下程序测试过的程序:

This is the program I tested it with:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1 {
    class Program {
        static void Main(string[] args) {
            for (int i = 0; i < 40; ++i) {
                string s = Ellipsis("Lorem ipsum dolor sit amet, amet consectetur adipiscing elit.", i);
                Console.WriteLine("{0} : {1}", i, s);
            }
        }

        static public string Ellipsis(string text, int length) {
          if (text.Length <= length) return text;
          int pos = text.IndexOf(" ", length) ;
          if (pos >= 0)
            return text.Substring(0, pos) + "...";
          return text;
        }
    }
}

此处输出:

0 : Lorem...
1 : Lorem...
2 : Lorem...
3 : Lorem...
4 : Lorem...
5 : Lorem...
6 : Lorem ipsum...
7 : Lorem ipsum...
8 : Lorem ipsum...
9 : Lorem ipsum...
10 : Lorem ipsum...
11 : Lorem ipsum...
12 : Lorem ipsum dolor...
13 : Lorem ipsum dolor...
14 : Lorem ipsum dolor...
15 : Lorem ipsum dolor...
16 : Lorem ipsum dolor...
17 : Lorem ipsum dolor...
18 : Lorem ipsum dolor sit...
19 : Lorem ipsum dolor sit...
20 : Lorem ipsum dolor sit...
21 : Lorem ipsum dolor sit...
22 : Lorem ipsum dolor sit amet,...
23 : Lorem ipsum dolor sit amet,...
24 : Lorem ipsum dolor sit amet,...
25 : Lorem ipsum dolor sit amet,...
26 : Lorem ipsum dolor sit amet,...
27 : Lorem ipsum dolor sit amet,...
28 : Lorem ipsum dolor sit amet, amet...
29 : Lorem ipsum dolor sit amet, amet...
30 : Lorem ipsum dolor sit amet, amet...
31 : Lorem ipsum dolor sit amet, amet...
32 : Lorem ipsum dolor sit amet, amet...
33 : Lorem ipsum dolor sit amet, amet consectetur...
34 : Lorem ipsum dolor sit amet, amet consectetur...
35 : Lorem ipsum dolor sit amet, amet consectetur...
36 : Lorem ipsum dolor sit amet, amet consectetur...
37 : Lorem ipsum dolor sit amet, amet consectetur...
38 : Lorem ipsum dolor sit amet, amet consectetur...
39 : Lorem ipsum dolor sit amet, amet consectetur...

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