• 2009-01-24
•   WinForms, Mono 2.0

With all the DBMSs out there, text files are still widely used when developing applications. They are small, fast and do not require any library or application to be installed in the client machine. The System.IO.StreamReader and System.IO.StreamWriter are used to read and write text files to disk.

The following code demonstrates reading a file selected using the OpenFileDialog control and saving to a file using the SaveFileDialog control. The code works with the .NET Framework and Mono 2.0 and later.

private void openToolStripMenuItem_Click(object sender, EventArgs e)
{
    if (openFileDialog1.ShowDialog() == DialogResult.Cancel)
        return;

    System.IO.StreamReader Reader = new 
        System.IO.StreamReader(openFileDialog1.FileName);

    //clear the contents of the textbox
    textBox1.Clear();

    //read the whole file in one read and display it in the textbox
    textBox1.Text = Reader.ReadToEnd();

    Reader.Close();
}

private void saveToolStripMenuItem_Click(object sender, EventArgs e)
{
    if (saveFileDialog1.ShowDialog() == DialogResult.Cancel)
        return;

    System.IO.StreamWriter Writer = 
        new System.IO.StreamWriter(saveFileDialog1.FileName);

    Writer.Write(textBox1.Text);
    Writer.Close();
}