Exporting a .txt, no overwrite warning appears

Question

When executing the following code, I would expect a warning pop up dialog, which will ask if I am sure I would like to overwrite the file, but no pop up appears. Does anyone know a simple way to implement it? Without having to create my own custom window

XAML:

 <Grid>
    <TextBox x:Name="name"  Text="hi" />
    <Button x:Name="create_File" Click="create_File_Click" Content="make the notepad" Width="auto"/>
  </Grid>

c#:

 public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
    }

 public void createFile()
    {

     string text_line = string.Empty;
     string exportfile_name = "C:\\" + name.Text + ".txt";

     System.IO.StreamWriter objExport;
     objExport = new System.IO.StreamWriter(exportfile_name);

     string[] TestLines = new string[2];
                TestLines[0] = "****TEST*****";
                TestLines[1] = "successful";


                for (int i = 0; i < 2; i++)
                {
                    text_line = text_line + TestLines[i] + "\r\n";
                    objExport.WriteLine(TestLines[i]);

                }
              objExport.Close();
                MessageBox.Show("Wrote File");

  }
  private void create_File_Click(object sender, RoutedEventArgs e)
    {
        createFile();
    }
}

UPDATE

I was not using SaveFileDialog, Now I am and it works just how I would expect it too... thanks for the answers, here is what I have now:

 public void createFile()
    {
        string text_line = string.Empty;
        string export_filename = name.Text;


        Microsoft.Win32.SaveFileDialog dlg = new Microsoft.Win32.SaveFileDialog();
        dlg.FileName = export_filename; // Default file name
        dlg.DefaultExt = ".text"; // Default file extension
        dlg.Filter = "Text documents (.txt)|*.txt"; // Filter files by extension

        // Show save file dialog box
        Nullable<bool> result = dlg.ShowDialog();


        // save file
        System.IO.StreamWriter objExport;
        objExport = new System.IO.StreamWriter(dlg.FileName);

        string[] TestLines = new string[2];
        TestLines[0] = "****TEST*****";
        TestLines[1] = "successful";



        for (int i = 0; i < 2; i++)
        {
            text_line = text_line + TestLines[i] + "\r\n";
            objExport.WriteLine(TestLines[i]);

        }
        objExport.Close();


    }


    private void create_File_Click(object sender, RoutedEventArgs e)
    {
        createFile();
    }

}

Why would you expect a confirmation dialog to appear? You need to handle that logic yourself... also, you need to wrap your stream in a `using` block — musefan, Nov 25 '16 at 12:41
Why would you expect that? You are writing to a file directly with a `StreamWriter`, which is just a class not a UI element. The `SaveFileDialog` will ask for confirmation when selecting an existing file, but for the `StreamWriter` this makes no sense at all (otherwise applications without UI could never make use of the `StreamWriter`). — bassfader, Nov 25 '16 at 12:42

score 2 · Accepted Answer · edited May 23 '17 at 11:59

Asking the user whether the file should be overwritten is usually done when the file path is chosen, not when the file is actually written.

If you let the user choose the path using a SaveFileDialog, the OverwritePrompt property is set to true by default, resulting in the confirmation dialog you desire.

If you don't want to use the SaveFileDialog, you can use a MessageBox with the MessageBoxButtons.YesNo option.

score 2 · Answer 2 · answered Nov 25 '16 at 12:42

2

1) Check if the File exists (File.Exists)

2) If it does, display a MessageBox (MessageBox.Show) with yes and no options.

3) Check if the user clicked yes, and only then execute the rest of your code

answered Nov 25 '16 at 12:42

Sylence

2,975
2
24
31

@thanks for giving me a way to do it with the method I was using, but the SaveFileDialog makes more sense, just didn't know about it – JohnChris Nov 25 '16 at 12:49

score 1 · Answer 3 · answered Nov 25 '16 at 12:48

1

DialogResult dialogResult = File.Exists(exportfile_name)
    ? MessageBox.Show(null, "Sure?", "Some Title", MessageBoxButtons.YesNo) 
    : DialogResult.Yes;

if (dialogResult == DialogResult.Yes)
{
    // save file
}

answered Nov 25 '16 at 12:48

Maksim Eroshkin

31
1
4

Exporting a .txt, no overwrite warning appears

3 Answers3