C# 5.0 Programmer's Reference

686 ❘ APPENDIX A Solutions to Exercises
}
if (File.Exists("Notes.txt"))
{
// Read the file.
using (StreamReader reader = new StreamReader("Notes.txt"))
{
notesTextBox.Text = reader.ReadToEnd();
}
}
// Save the file.
private void Form1_FormClosing(object sender, FormClosingEventArgs e)
{
using (StreamWriter writer = File.CreateText("Notes.txt"))
{
writer.Write(notesTextBox.Text);
}
}
4. The WriteLine method adds a new line after the text it is writing into the file. When the program
starts, it reads that new line as part of the text it displays in the TextBox. If the program
uses WriteLine to save the text, it will write the original new line plus another one into the file.
The result is the program adds another new line every time it starts and stops. (Try it and see.)
You can avoid that by using the Write method instead of WriteLine.
5. The LoadAndSaveFileWithPrompt example program uses the following Form_Closing
event handler to prompt the user if the text file exists.
// Save the file.
private void Form1_FormClosing(object sender, FormClosingEventArgs e)
{
// See if the file exists.
if (File.Exists("Notes.txt"))
{
// Prompt the user.
DialogResult result =
MessageBox.Show("The file exists. Do you want to overwrite it",
"Overwrite",
MessageBoxButtons.YesNoCancel,
MessageBoxIcon.Question);
// If the user clicked No, exit without saving.
if (result == DialogResult.No) return;
// If the user clicked Cancel, cancel.
if (result == DialogResult.Cancel)
{
e.Cancel = true;
return;
}
}
// If the user clicked Yes, continue to overwrite the file.
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