Windows系统中使用C#读取文本文件内容的小示例

读取文本文件中的内容

此示例读取文本文件的内容以使用 system.io.file 选件类的静态方法 readalltext 和 readalllines。

class readfromfile
{
  static void main()
  {
    // the files used in this example are created in the topic
    // how to: write to a text file. you can change the path and
    // file name to substitute text files of your own.

    // example #1
    // read the file as one string.
    string text = system.io.file.readalltext(@"c:\users\public\testfolder\writetext.txt");

    // display the file contents to the console. variable text is a string.
    system.console.writeline("contents of writetext.txt = {0}", text);

    // example #2
    // read each line of the file into a string array. each element
    // of the array is one line of the file.
    string[] lines = system.io.file.readalllines(@"c:\users\public\testfolder\writelines2.txt");

    // display the file contents by using a foreach loop.
    system.console.writeline("contents of writelines2.txt = ");
    foreach (string line in lines)
    {
      // use a tab to indent each line of the file.
      console.writeline("\t" + line);
    }

    // keep the console window open in debug mode.
    console.writeline("press any key to exit.");
    system.console.readkey();
  }
}

一次一行地读取文本文件
本示例使用 streamreader 类的 readline 方法将文本文件的内容读取（一次读取一行）到字符串中。所有文本行都保存在字符串 line 中并显示在屏幕上。

int counter = 0;
string line;

// read the file and display it line by line.
system.io.streamreader file = 
  new system.io.streamreader(@"c:\test.txt");
while((line = file.readline()) != null)
{
  system.console.writeline (line);
  counter++;
}

file.close();
system.console.writeline("there were {0} lines.", counter);
// suspend the screen.
system.console.readline();