Question

I am currently working Open file and write file functions in C#. I am going through two problems: When the user is in the process of saving a file, if he/she exits the save dialog and nothing is saved I get an error(look at picture below for description). How can my program avoid this and not crash? and Is there away to display a message after the file has been saved?

 private void button2_Click(object sender, EventArgs e)
            {
                SaveFileDialog saveReport = new SaveFileDialog();
                saveReport.Filter = "Text Files | *.txt";
                saveReport.ShowDialog();

                StreamWriter writeFile = new StreamWriter(saveReport.FileName);
                writeFile.Write(textBox1.Text);
                writeFile.Close();

            }

Answer 1

You could do something like this:

var saveReport = new SaveFileDialog();
saveReport.Filter = "Text Files | *.txt";
var result = saveReport.ShowDialog();

if(result == DialogResult.Cancel || string.IsNullOrWhiteSpace(saveReport.FileName))
    return;

using(var writer = new StreamWriter(saveReport.FileName))
{
    writer.Write(textBox1.Text);
    writer.Close();
}

MessageBox.ShowDialog("File Saved!");

In principle the FileName will never be null or whitespace — the dialog prevents it unless you cancel, but I include it for clarity.