修改FileStream

Question

我現在正在開發一個允許編輯非常大的文本文件（4Gb +）的類。那麼它可能聽起來有點愚蠢，但我不明白我如何修改流中的文本。 這裏是我的代碼：

public long Replace(String text1, String text2) 
{ 
    long replaceCount = 0; 
    currentFileStream = File.Open(CurrentFileName, FileMode.Open, FileAccess.ReadWrite, FileShare.None); 

    using (BufferedStream bs = new BufferedStream(currentFileStream)) 
    using (StreamReader sr = new StreamReader(bs)) 
    { 
     string line; 
     while ((line = sr.ReadLine()) != null) 
     { 
      if (line.Contains(text1)) 
      { 
       line.Replace(text1, text2); 

       // Here I should save changed line 
       replaceCount++; 
      } 
     } 
    } 
    return replaceCount; 
} 

Answer 1

您不打算裝在你的代碼的任何地方。您應該保存所有文本，然後再將其寫入文件。像，

public long Replace(String text1, String text2) 
{ 
    long replaceCount = 0; 
    currentFileStream = File.Open(CurrentFileName, FileMode.Open, FileAccess.ReadWrite, FileShare.None); 
StringBuilder sb = new StringBuilder(); 
using (BufferedStream bs = new BufferedStream(currentFileStream)) 
using (StreamReader sr = new StreamReader(bs)) 
{ 
    string line; 
    while ((line = sr.ReadLine()) != null) 
    { 
     string textToAdd = line; 
     if (line.Contains(text1)) 
     { 
      textToAdd = line.Replace(text1, text2); 

      // Here I should save changed line 
      replaceCount++; 
     } 
     sb.Append(textToAdd); 
    } 
} 
using (FileStream fileStream = new FileStream(filename , fileMode, fileAccess)) 
     { 
      StreamWriter streamWriter = new StreamWriter(fileStream); 
      streamWriter.Write(sb.ToString()); 
      streamWriter.Close(); 
      fileStream.Close(); 
     } 
return replaceCount; 

}