How to: Read a Text File (C++/CLI)

The following code example demonstrates how to open and read a text file one line at a time, by using the StreamReader class that's defined in the System.IO namespace. An instance of this class is used to open a text file and then the StreamReader.ReadLine method is used to retrieve each line.

This code example reads a file that's named textfile.txt and contains text. For information about this kind of file, see How to: Write a Text File (C++/CLI).

// text_read.cpp
// compile with: /clr
using namespace System;
using namespace System::IO;

int main()
   String^ fileName = "textfile.txt";
      Console::WriteLine("trying to open file {0}...", fileName);
      StreamReader^ din = File::OpenText(fileName);

      String^ str;
      int count = 0;
      while ((str = din->ReadLine()) != nullptr) 
         Console::WriteLine("line {0}: {1}", count, str );
   catch (Exception^ e)
      if (dynamic_cast<FileNotFoundException^>(e))
         Console::WriteLine("file '{0}' not found", fileName);
         Console::WriteLine("problem reading file '{0}'", fileName);

   return 0;
Was this page helpful?
(1500 characters remaining)
Thank you for your feedback

Community Additions

© 2015 Microsoft