的StreamWriter重寫文件或追加到該文件

Question

我用這

for($number=0; $number < 5; $number++){ 
StreamWriter x = new StreamWriter("C:\\test.txt"); 
       x.WriteLine(number); 
       x.Close(); 

} 

如果事情是在test.text，該代碼不會覆蓋它。我使用C＃

Answer 1

嘗試的FileMode枚舉：

 FileStream fappend = File.Open("C:\\test.txt", FileMode.Append); // will append to end of file 

     FileStream fcreate = File.Open("C:\\test.txt", FileMode.Create); // will create the file or overwrite it if it already exists 

Answer 2

2個問題

1: how can I make it overwrite the file 
2: how can I append to the same file 

您可以通過使用FILESTREAM，然後傳遞，爲您的StreamWriter的開始。

FileStream fsOverwrite = new FileStream("C:\\test.txt", FileMode.Create); 
StreamWriter swOverwrite = new StreamWriter(fsOverwrite); 

或

FileStream fsAppend = new FileStream("C:\\test.txt", FileMode.Append);  
StreamWriter swAppend = new StreamWriter(fsAppend); 

Answer 3

StreamWriters默認行爲是，如果它的存在是爲了創建一個新的文件，或者將其覆蓋。要附加到文件，您需要使用接受布爾值的重載並將其設置爲true。在您的示例代碼中，您將重寫5次test.txt。

using(var sw = new StreamWriter(@"c:\test.txt", true)) 
{ 
    for(int x = 0; x < 5; x++) 
    { 
     sw.WriteLine(x);  
    } 
} 

Answer 4

那麼，什麼是你的代碼的結果呢？

我期望文件只包含數字4，因爲默認行爲是創建/覆蓋，但是您說它不覆蓋？

你應該能夠通過做你正在做的事情來覆蓋文件，並且可以通過使用FileMode.Append創建FileStream來追加文件。

Answer 5

你可以傳遞第二個參數來StreamWriter到enable或disable附加到文件：

在C#.Net：

using System.IO; 

// This will enable appending to file. 
StreamWriter stream = new StreamWriter("YourFilePath", true); 

// This is default mode, not append to file and create a new file. 
StreamWriter stream = new StreamWriter("YourFilePath", false); 
// or 
StreamWriter stream = new StreamWriter("YourFilePath"); 

在C++.Net(C++/CLI)：

using namespace System::IO; 

// This will enable appending to file. 
StreamWriter^ stream = gcnew StreamWriter("YourFilePath", true); 

// This is default mode, not append to file and create a new file. 
StreamWriter^ stream = gcnew StreamWriter("YourFilePath", false); 
// or 
StreamWriter^ stream = gcnew StreamWriter("YourFilePath");