Estou tentando implementar reticências na Umbraco, com o requisito de 15 caracteres de introdução, mas sempre terminando com uma palavra completa.

Pensei em usar o XSLT, mas depois percebi que posso usar um método de extensão simples escrito em C #.

Eu posso facilmente substring o texto e anexar "...", mas estou preso com a questão de ter que terminar com uma palavra completa. Aqui está o meu código até agora (muito complicado: p)

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

Texto de exemplo

Lorem ipsum dolor sente-se no meio, no meio consectetur da elite adipiscing.

Se implementássemos o método de reticências acima (length = 15), a saída pareceria

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

Gostaria de garantir que nenhuma palavra seja cortada, para que a saída pareça

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

Qualquer ajuda apreciada.

EDITAR

Depois de executar a amostra do código abaixo, parece que, se o comprimento das reticências terminar na última palavra, nenhum texto será exibido.

Aqui está a saída, veja a linha 56-60

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.

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