如何在 C# 中读取和写入文件
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How to both read and write a file in C#
提问by
I want to both read from and write to a file. This doesn't work.
我想读取和写入文件。这不起作用。
static void Main(string[] args)
{
StreamReader sr = new StreamReader(@"C:\words.txt");
StreamWriter sw = new StreamWriter(@"C:\words.txt");
}
How can I both read from and write to a file in C#?
如何在 C# 中读取和写入文件？
回答by MikeW
You need a single stream, opened for both reading and writing.
您需要一个单一的流，为读取和写入而打开。
FileStream fileStream = new FileStream(
@"c:\words.txt", FileMode.OpenOrCreate,
FileAccess.ReadWrite, FileShare.None);
回答by ScottS
var fs = File.Open("file.name", FileMode.OpenOrCreate, FileAccess.ReadWrite);
var sw = new StreamWriter(fs);
var sr = new StreamReader(fs);
...
fs.Close();
//or sw.Close();
The key thing is to open the file with the FileAccess.ReadWrite flag. You can then create whatever Stream/String/Binary Reader/Writers you need using the initial FileStream.
关键是用 FileAccess.ReadWrite 标志打开文件。然后，您可以使用初始 FileStream 创建您需要的任何 Stream/String/Binary Reader/Writers。
回答by ScottS
Don't forget the easy route:
不要忘记简单的路线：
static void Main(string[] args)
{
var text = File.ReadAllText(@"C:\words.txt");
File.WriteAllText(@"C:\words.txt", text + "DERP");
}
回答by mbarthelemy
This thread seems to answer your question : simultaneous-read-write-a-file
该线程似乎回答了您的问题：同时读取-写入-文件
Basically, what you need is to declare two FileStream, one for read operations, the other for write operations. Writer Filestream needs to open your file in 'Append' mode.
基本上，您需要声明两个 FileStream，一个用于读取操作，另一个用于写入操作。Writer Filestream 需要以“附加”模式打开您的文件。
回答by Ipsita Paul
you can try this:"Filename.txt" file will be created automatically in the bin->debug folder everytime you run this code or you can specify path of the file like: @"C:/...". you can check ?xistance of "Hello" by going to the bin -->debug folder
你可以试试这个：“Filename.txt”文件将在每次运行此代码时自动在 bin->debug 文件夹中创建，或者你可以指定文件的路径，如：@"C:/..."。您可以通过转到 bin -->debug 文件夹来检查“Hello”的 ?xistance
P.S dont forget to add Console.Readline() after this code snippet else console will not appear.
PS 不要忘记在此代码片段之后添加 Console.Readline() 否则控制台将不会出现。
TextWriter tw = new StreamWriter("filename.txt");
String text = "Hello";
tw.WriteLine(text);
tw.Close();
TextReader tr = new StreamReader("filename.txt");
Console.WriteLine(tr.ReadLine());
tr.Close();
回答by Anonimys
Made an improvement code by @Ipsita - for use asynchronous read\writefile I/O
由@Ipsita 改进代码 - 用于异步读写文件 I/O
readonly string logPath = @"FilePath";
...
public async Task WriteToLogAsync(string dataToWrite)
{
TextReader tr = new StreamReader(logPath);
string data = await tr.ReadLineAsync();
tr.Close();
TextWriter tw = new StreamWriter(logPath);
await tw.WriteLineAsync(data + dataToWrite);
tw.Close();
}
...
await WriteToLogAsync("Write this to file");
