StringBuilder ReplaceAt功能

Question

我有一個stringbuilder，我操縱了好幾次，我需要用不同長度的字符串替換它內部的字符串。

sb = new StringBuilder("This has {Count} Values. Your search was '{SearchText}'. Did you mean '{DidYouMean}'?") 
//get the replacement areas, this would search for the field names within {} 
MatchCollection matches = GetReplacementAreas(sb); 

int indexOffset=0; 
foreach(Match m in matches) 
{ 
    //fields is a dictionary containing keys that match the fields 
    sb.ReplaceAt(m.Index,m.Length,fields[m.Value]); 
} 

很明顯ReplaceAt不存在。我即將自己寫。其他人已經這樣做了嗎？

Answer 1

public static class StringBuilderExtensions 
{ 
#if EXTENSIONS_SUPPORTED 
    public static StringBuilder ReplaceAt(this StringBuilder sb, string value, int index, int count) 
    { 
     return StringBuilderExtensions.ReplaceAt(sb, value, index, count); 
    } 
#endif 

    public static StringBuilder ReplaceAt(StringBuilder sb, string value, int index, int count) 
    { 
     if (value == null) 
     { 
      sb.Remove(index, count); 
     } 
     else 
     { 
      int lengthOfValue = value.Length; 

      if (lengthOfValue > count) 
      { 
       string valueToInsert = value.Substring(count); 
       sb.Insert(index + count, valueToInsert); 
      } 
      if (lengthOfValue < count) 
      { 
       sb.Remove(index + count, lengthOfValue - count); 
      } 

      char[] valueChars = value.ToCharArray(); 
      for (int i = 0; i < lengthOfValue; i++) 
      { 
       sb[index + i] = valueChars[i]; 
      } 
     } 

     return sb; 
    } 
}