C＃提示警告用户覆盖.txt文件

Question

Not sure how to implement this, i am not using SaveFileDialog which i have seen uses OverWritePrompt = true cant seem to get that to work for me.

I am using WPF.

The structure:-

I have a textBox called filePathBox - This contains a file path used from opening an: OpenFileDialog

private void fileBrowser_Click(object sender, RoutedEventArgs e)
        {

            //Firstly creating the OpenFileDialog
            Microsoft.Win32.OpenFileDialog dlg = new Microsoft.Win32.OpenFileDialog();

            //Setting the filter for the file extension of the files as well as the default extension
            dlg.DefaultExt = ".txt";
            dlg.Filter = "All Files|*.*";

            //Display the dialog box by calling the ShowDialog method
            Nullable<bool> result = dlg.ShowDialog();

            //Grab the file you selected and display it in filePathBox
            if (result == true)
            {
                //Open The document
                string filename = dlg.FileName;
                filePathBox.Text = filename;
            }
        }

You can then click a button and the .txt file displays in a textBox called textResult

private void helpfulNotes_Click(object sender, RoutedEventArgs e)
        {


            if (File.Exists(filePathBox.Text) && System.IO.Path.GetExtension(filePathBox.Text).ToLower() == ".txt")
            {
                textResult.Text = File.ReadAllText(filePathBox.Text);
            }

            if (string.IsNullOrWhiteSpace(filePathBox.Text))
            {
                MessageBox.Show("Please choose a file by clicking on the folder Icon :(");
            }

        }

Once you have made changes to that text in 'textResult' i have a button to save the text back to the file path that was originally loaded using the OpenFileDialog

private void saveText_Click(object sender, RoutedEventArgs e)
        {
            if (string.IsNullOrEmpty(textResult.Text))
            {
                saveText.IsEnabled = false;
                MessageBox.Show("No Text to save!");
            }
            else
            {
                saveText.IsEnabled = true;

                string test = textResult.Text;
                System.IO.File.WriteAllText(filePathBox.Text, test);
            }

            //fileSaveIcon.Visibility = Visibility.Visible;
            //fileChangedIcon.Visibility = Visibility.Hidden;

        }

At the moment it all saves fine, only it doesn't prompt the user saying are you sure you want to overwrite the file.

At the moment i could

1. load a file for the purpose of this named TestNote.txt into the filePathBox
2. Type some text in textResult before even clicking to display the file
3. Click save and it would just overwrite TestNote.txt with the text i just entered without even warning me

Hopefully i have explained this adequately and provided all the code you need

Answer 1

Just add a messagebox to show your alert message before writing to the text file.

private void saveText_Click(object sender, RoutedEventArgs e)
        {
            if (string.IsNullOrEmpty(textResult.Text))
            {
                saveText.IsEnabled = false;
                MessageBox.Show("No Text to save!");
            }
            else
            {
        if(MessageBox.Show("are you sure you want to overwrite the file.", "Alert", MessageBoxButtons.YesNo)==DialogResult.Yes)
        {
                saveText.IsEnabled = true;
                string test = textResult.Text;
                System.IO.File.WriteAllText(filePathBox.Text, test);
                }
            }

            //fileSaveIcon.Visibility = Visibility.Visible;
            //fileChangedIcon.Visibility = Visibility.Hidden;

        }

Answer 2

Well, OverWritePrompt is a SaveFileDialog property, which you're not using: you're always using File.WriteAllText() , which always overwrites the target file.

You want to provide a Save function that saves an earlier opened file without prompt, a Save As function that prompts the user for a new filename and also call Save As when saving a new file.

This is implemented like this, pseudo:

private string _currentlyOpenedFile;

public void FileOpen_Click(...)
{
    var openFileDialog = new ...OpenFileDialog();

    if (openFileDialog.ShowDialog())
    {
        // Save the filename when opening a file.
        _currentlyOpenedFile = openFileDialog.FileName;
    }
}

public void FileNew_Click(...)
{
    // Clear the filename when closing a file or making a new file.
    _currentlyOpenedFile = null;
}

public void FileSave_Click(...)
{
    if (_currentlyOpenedFile == null)
    {
        // New file, treat as SaveAs
        FileSaveAs_Click();
        return;
    }
}

public void FileSaveAs_Click(...)
{
    var saveFileDialog = new ...SaveFileDialog();

    if (openFileDialog.ShowDialog())
    {
        // Write the file.
        File.WriteAllText(text, openFileDialog.FileName);

        // Save the filename after writing the file.
        _currentlyOpenedFile = openFileDialog.FileName;
    }
}

Here you'll be leveraging the SaveFileDialog's functionality which prompts the user whether they want to overwrite an already existing file.