asp. net下使用foreach简化文本文件的访问。_.net

asp. net下使用foreach简化文本文件的访问。

       很多时候，我们总是按照行的方式访问文本文件，使用foreach语句能够极大地简化访问逻辑：例如：
foreach (string line in new linereader(”c:\abc.txt”))
  console.writeline(line);
完整代码如下：
using system;
using system.io;
using system.text;
using system.collections;
namespace forks.utils.io
{
    public struct linereader : idisposable
    {
    public linereader(string file, encoding encoding) : this(file, encoding, false)
        {
    }
    public linereader(string file, encoding encoding, bool ignoreblanklines) : this(new filestream(file, filemode.open, fileaccess.read, fileshare.read), encoding, ignoreblanklines)
    {
    }
    public linereader(stream stream, encoding encoding) : this(stream, encoding, false)
    {
    }
    public linereader(stream stream, encoding encoding, bool ignoreblanklines) : this(new streamreader(stream, encoding), ignoreblanklines)
    {
    }
    public linereader(textreader reader) : this(reader, false)
    {
    }
    textreader mreader;
    bool mignoreblanklines;
    public linereader(textreader reader, bool ignoreblanklines)
    {
      mreader = reader;
      mignoreblanklines = ignoreblanklines;
      mcurrent = null;
    }
    public linereader getenumerator()
    {
      return this;
    }
    public void reset()
    {
      throw new notsupportedexception("linereaderö»äü¶áè¡ò»´î");
    }
    string mcurrent;
    public string current
    {
      get
      {
        return mcurrent;
      }
    }
    public bool movenext()
    {
      do
      {
        mcurrent = mreader.readline();
      }while (mignoreblanklines && mcurrent != null && mcurrent.length == 0);
      return mcurrent != null;
    }
    public void dispose()
    {
      mreader.close();
    }
  }
}
测试代码：
using system;
using system.io;
using system.text;
using nunit.framework;
using forks.test;
namespace forks.utils.io
{
  [testfixture]
    public class linereadertest
    {
    const string testlines = @"abc asd ewr afa e
  start with blanks
end with blanks
ºº×öabc123!@#
end of text!";
    [test]
    public void readfromreader()
    {
      dotest(new linereader(new stringreader(testlines)));
    }
    [test]
    public void readfromfile()
    {
      string file = path.gettempfilename();
      try
      {
        stringutil.savetofile(testlines, file, encoding.getencoding("gb2312"));
        dotest(new linereader(file, encoding.getencoding("gb2312")));
      }
      finally
      {
        fileutil.safedelete(file);
      }
    }
    [test]
    public void readfromstream()
    {
      string file = path.gettempfilename();
      try
      {
        stringutil.savetofile(testlines, file, encoding.getencoding("gb2312"));
        using (stream stream = new filestream(file, filemode.open))
          dotest(new linereader(stream, encoding.getencoding("gb2312")));
      }
      finally
      {
        fileutil.safedelete(file);
      }
    }
    void dotest(linereader reader)
    {
      stringbuilder sb = new stringbuilder();
      foreach (string line in reader)
        sb.append(line + environment.newline);
      assert.areequal(testlines + environment.newline, sb.tostring());
    }
    [test]
    public void ignoreblankline()
    {
      foreach (string line in new linereader(new stringreader(testlines), true))
        assert.istrue(line.length != 0);
    }
    }
}