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).
Example
// text_read.cpp
// compile with: /clr
#using<system.dll>
using namespace System;
using namespace System::IO;
int main()
{
String^ fileName = "textfile.txt";
try
{
Console::WriteLine("trying to open file {0}...", fileName);
StreamReader^ din = File::OpenText(fileName);
String^ str;
int count = 0;
while ((str = din->ReadLine()) != nullptr)
{
count++;
Console::WriteLine("line {0}: {1}", count, str );
}
}
catch (Exception^ e)
{
if (dynamic_cast<FileNotFoundException^>(e))
Console::WriteLine("file '{0}' not found", fileName);
else
Console::WriteLine("problem reading file '{0}'", fileName);
}
return 0;
}