在 C# 中存储目录路径

Question

I have to make a folder path reusable. When I open a folder the program must save it's directory one time so I can instantly reopen it when clicking the button without navigation in the folders. I thought I create a string and store the path directory in it for a time.

How can I make this work? I store the filepath in a textbox for now:

OpenFileDialog openFileDialog1 = new OpenFileDialog
        {
            InitialDirectory = @"D:\",
            Title = "Browse Text Files",

            CheckFileExists = true,
            CheckPathExists = true,

            DefaultExt = "txt",
            Filter = "txt files (*.txt)|*.txt",
            FilterIndex = 2,
            RestoreDirectory = true,

            ReadOnlyChecked = true,
            ShowReadOnly = true
        };

        if (openFileDialog1.ShowDialog() == DialogResult.OK)
        {
            textBox1.Text = openFileDialog1.FileName;
        }

Answer 1

You could use a static string variable:

private const string initDefaultPath = @"D:\"; // <-- initial default folder path
private static string prevFolderPath = initDefaultPath;

//Let's suppose a button click event
public void Button1_Click(object sender, EventArgs e)
{
    OpenFileDialog openFileDialog1 = new OpenFileDialog
    {
        InitialDirectory = string.IsNullOrWhiteSpace(prevFolderPath)
            ? initDefaultPath
            : prevFolderPath,

        Title = "Browse Text Files",
        CheckFileExists = true,
        CheckPathExists = true,
        DefaultExt = "txt",
        Filter = "txt files (*.txt)|*.txt",
        FilterIndex = 2,
        RestoreDirectory = true,
        ReadOnlyChecked = true,
        ShowReadOnly = true
    };

    if (openFileDialog1.ShowDialog() == DialogResult.OK)
    {
        textBox1.Text = openFileDialog1.FileName;
        prevFolderPath = Path.GetDirectoryName(openFileDialog1.FileName);
    }
}

Answer 2

I think what you need is for a way your form to remember for example the last used path. The official way of doing this to go to project properties and then into settings and add a new setting value of type string to store path or filename information.

Then you need two more things.

• Bind a textbox to the property for display purposes if needed. You do this manually in a .NET Core application by adding the following code into the Form1.Designer.cs file

  private void InitializeComponent() { ... this.textBox1.DataBindings.Add( new System.Windows.Forms.Binding("Text", global::WindowsFormsApp1.Properties.Settings.Default, "lastPath", true, System.Windows.Forms.DataSourceUpdateMode.OnPropertyChanged)); ... }

  Or if you are with .NET Framework then there is a UI option for the textbox under ApplicationSettings .

• The last item you need for the form to save the settings when it is closing. This is done by handling the FormClosing event

   private void Form1_FormClosing(object sender, FormClosingEventArgs e) { Properties.Settings.Default.Save(); }

Now your code can read and write to the textbox what it needs, and the settings file is going to kelp synchronized. For example in file opening operation, if you wish to store last lath in the textbox then do the following:

    private void button1_Click(object sender, EventArgs e)
    {
        OpenFileDialog openFileDialog1 = new OpenFileDialog
        {
            InitialDirectory = textBox1.Text,
            Title = "Browse Text Files",

            CheckFileExists = true,
            CheckPathExists = true,

            DefaultExt = "txt",
            Filter = "txt files (*.txt)|*.txt",
            FilterIndex = 2,
            RestoreDirectory = true,

            ReadOnlyChecked = true,
            ShowReadOnly = true
        };

        if (openFileDialog1.ShowDialog() == DialogResult.OK)
        {
            textBox1.Text = System.IO.Path.GetDirectoryName(openFileDialog1.FileName);
        }

This way each time the application is launched it remembers the contents of the text box

---

Note that the application will create a settings XML file in the following location:

Answer 3

You can use Path.GetFullPath

if (openFileDialog1.ShowDialog() == DialogResult.OK)
{
    textBox1.Text = Path.GetFullPath(openFileDialog1.FileName);
}

Answer 4

You could store the path in a variable using what Jamiec said

then you would open the file a second time using system.io.open()

link to the documentation