FolderBrowserDialog Costruttore

public:
 FolderBrowserDialog();

public FolderBrowserDialog ();

Public Sub New ()

Esempio

Nell'esempio di codice seguente viene creata un'applicazione che consente all'utente di aprire i file rich text (.rtf) all'interno del RichTextBox controllo.

// The following example displays an application that provides the ability to
// open rich text files (rtf) into the RichTextBox. The example demonstrates
// using the FolderBrowserDialog to set the default directory for opening files.
// The OpenFileDialog is used to open the file.
#using <System.dll>
#using <System.Windows.Forms.dll>
#using <System.Drawing.dll>

using namespace System;
using namespace System::Drawing;
using namespace System::Windows::Forms;
using namespace System::IO;
public ref class FolderBrowserDialogExampleForm: public System::Windows::Forms::Form
{
private:
   FolderBrowserDialog^ folderBrowserDialog1;
   OpenFileDialog^ openFileDialog1;
   RichTextBox^ richTextBox1;
   MainMenu^ mainMenu1;
   MenuItem^ fileMenuItem;
   MenuItem^ openMenuItem;
   MenuItem^ folderMenuItem;
   MenuItem^ closeMenuItem;
   String^ openFileName;
   String^ folderName;
   bool fileOpened;

public:

   // Constructor.
   FolderBrowserDialogExampleForm()
   {
      fileOpened = false;
      this->mainMenu1 = gcnew System::Windows::Forms::MainMenu;
      this->fileMenuItem = gcnew System::Windows::Forms::MenuItem;
      this->openMenuItem = gcnew System::Windows::Forms::MenuItem;
      this->folderMenuItem = gcnew System::Windows::Forms::MenuItem;
      this->closeMenuItem = gcnew System::Windows::Forms::MenuItem;
      this->openFileDialog1 = gcnew System::Windows::Forms::OpenFileDialog;
      this->folderBrowserDialog1 = gcnew System::Windows::Forms::FolderBrowserDialog;
      this->richTextBox1 = gcnew System::Windows::Forms::RichTextBox;
      this->mainMenu1->MenuItems->Add( this->fileMenuItem );
      array<System::Windows::Forms::MenuItem^>^temp0 = {this->openMenuItem,this->closeMenuItem,this->folderMenuItem};
      this->fileMenuItem->MenuItems->AddRange( temp0 );
      this->fileMenuItem->Text = "File";
      this->openMenuItem->Text = "Open...";
      this->openMenuItem->Click += gcnew System::EventHandler( this, &FolderBrowserDialogExampleForm::openMenuItem_Click );
      this->folderMenuItem->Text = "Select Directory...";
      this->folderMenuItem->Click += gcnew System::EventHandler( this, &FolderBrowserDialogExampleForm::folderMenuItem_Click );
      this->closeMenuItem->Text = "Close";
      this->closeMenuItem->Click += gcnew System::EventHandler( this, &FolderBrowserDialogExampleForm::closeMenuItem_Click );
      this->closeMenuItem->Enabled = false;
      this->openFileDialog1->DefaultExt = "rtf";
      this->openFileDialog1->Filter = "rtf files (*.rtf)|*.rtf";
      
      // Set the help text description for the FolderBrowserDialog.
      this->folderBrowserDialog1->Description = "Select the directory that you want to use as the default.";
      
      // Do not allow the user to create new files via the FolderBrowserDialog.
      this->folderBrowserDialog1->ShowNewFolderButton = false;
      
      // Default to the My Documents folder.
      this->folderBrowserDialog1->RootFolder = Environment::SpecialFolder::Personal;
      this->richTextBox1->AcceptsTab = true;
      this->richTextBox1->Location = System::Drawing::Point( 8, 8 );
      this->richTextBox1->Size = System::Drawing::Size( 280, 344 );
      this->richTextBox1->Anchor = static_cast<AnchorStyles>(AnchorStyles::Top | AnchorStyles::Left | AnchorStyles::Bottom | AnchorStyles::Right);
      this->ClientSize = System::Drawing::Size( 296, 360 );
      this->Controls->Add( this->richTextBox1 );
      this->Menu = this->mainMenu1;
      this->Text = "RTF Document Browser";
   }


private:

   // Bring up a dialog to open a file.
   void openMenuItem_Click( Object^ /*sender*/, System::EventArgs^ /*e*/ )
   {
      
      // If a file is not opened then set the initial directory to the
      // FolderBrowserDialog::SelectedPath value.
      if (  !fileOpened )
      {
         openFileDialog1->InitialDirectory = folderBrowserDialog1->SelectedPath;
         openFileDialog1->FileName = nullptr;
      }

      
      // Display the openFile Dialog.
      System::Windows::Forms::DialogResult result = openFileDialog1->ShowDialog();
      
      // OK button was pressed.
      if ( result == ::DialogResult::OK )
      {
         openFileName = openFileDialog1->FileName;
         try
         {
            
            // Output the requested file in richTextBox1.
            Stream^ s = openFileDialog1->OpenFile();
            richTextBox1->LoadFile( s, RichTextBoxStreamType::RichText );
            s->Close();
            fileOpened = true;
         }
         catch ( Exception^ exp ) 
         {
            MessageBox::Show( String::Concat( "An error occurred while attempting to load the file. The error is: ", System::Environment::NewLine, exp, System::Environment::NewLine ) );
            fileOpened = false;
         }

         Invalidate();
         closeMenuItem->Enabled = fileOpened;
      }
      // Cancel button was pressed.
      else
      
      // Cancel button was pressed.
      if ( result == ::DialogResult::Cancel )
      {
         return;
      }
   }


   // Close the current file.
   void closeMenuItem_Click( Object^ /*sender*/, System::EventArgs^ /*e*/ )
   {
      richTextBox1->Text = "";
      fileOpened = false;
      closeMenuItem->Enabled = false;
   }


   // Bring up a dialog to chose a folder path in which to open/save a file.
   void folderMenuItem_Click( Object^ /*sender*/, System::EventArgs^ /*e*/ )
   {
      
      // Show the FolderBrowserDialog.
      System::Windows::Forms::DialogResult result = folderBrowserDialog1->ShowDialog();
      if ( result == ::DialogResult::OK )
      {
         folderName = folderBrowserDialog1->SelectedPath;
         if (  !fileOpened )
         {
            
            // No file is opened, bring up openFileDialog in selected path.
            openFileDialog1->InitialDirectory = folderName;
            openFileDialog1->FileName = nullptr;
            openMenuItem->PerformClick();
         }
      }
   }

};


// The main entry point for the application.
int main()
{
   Application::Run( gcnew FolderBrowserDialogExampleForm );
}

// The following example displays an application that provides the ability to 
// open rich text files (rtf) into the RichTextBox. The example demonstrates 
// using the FolderBrowserDialog to set the default directory for opening files.
// The OpenFileDialog class is used to open the file.
using System;
using System.Drawing;
using System.Windows.Forms;
using System.IO;

public class FolderBrowserDialogExampleForm : System.Windows.Forms.Form
{
    private FolderBrowserDialog folderBrowserDialog1;
    private OpenFileDialog openFileDialog1;

    private RichTextBox richTextBox1;

    private MenuStrip mainMenu1;
    private ToolStripMenuItem fileMenuItem, openMenuItem;
    private ToolStripMenuItem folderMenuItem, closeMenuItem;

    private string openFileName, folderName;

    private bool fileOpened = false;

    // The main entry point for the application.
    [STAThreadAttribute]
    static void Main()
    {
        Application.Run(new FolderBrowserDialogExampleForm());
    }

    // Constructor.
    public FolderBrowserDialogExampleForm()
    {
        this.mainMenu1 = new MenuStrip();

        this.fileMenuItem = new ToolStripMenuItem();
        this.openMenuItem = new ToolStripMenuItem();
        this.folderMenuItem = new ToolStripMenuItem();
        this.closeMenuItem = new ToolStripMenuItem();

        this.openFileDialog1 = new OpenFileDialog();
        this.folderBrowserDialog1 = new FolderBrowserDialog();
        this.richTextBox1 = new RichTextBox();

        this.mainMenu1.Items.Add(this.fileMenuItem);

        this.fileMenuItem.Text = "File";
        this.fileMenuItem.DropDownItems.AddRange(
            new ToolStripItem[] {
                this.openMenuItem,
                this.closeMenuItem,
                this.folderMenuItem
            }
        );

        this.openMenuItem.Text = "Open...";
        this.openMenuItem.Click += new EventHandler(this.openMenuItem_Click);

        this.folderMenuItem.Text = "Select Directory...";
        this.folderMenuItem.Click += new EventHandler(this.folderMenuItem_Click);

        this.closeMenuItem.Text = "Close";
        this.closeMenuItem.Click += new EventHandler(this.closeMenuItem_Click);
        this.closeMenuItem.Enabled = false;

        this.openFileDialog1.DefaultExt = "rtf";
        this.openFileDialog1.Filter = "rtf files (*.rtf)|*.rtf";

        // Set the help text description for the FolderBrowserDialog.
        this.folderBrowserDialog1.Description =
            "Select the directory that you want to use as the default.";

        // Do not allow the user to create new files via the FolderBrowserDialog.
        this.folderBrowserDialog1.ShowNewFolderButton = false;

        // Default to the My Documents folder.
        this.folderBrowserDialog1.RootFolder = Environment.SpecialFolder.Personal;

        this.richTextBox1.AcceptsTab = true;
        this.richTextBox1.Location = new System.Drawing.Point(8, 40);
        this.richTextBox1.Size = new System.Drawing.Size(280, 312);
        this.richTextBox1.Anchor = (
            AnchorStyles.Top |
            AnchorStyles.Left |
            AnchorStyles.Bottom |
            AnchorStyles.Right
        );

        this.ClientSize = new System.Drawing.Size(296, 360);
        this.Controls.Add(this.mainMenu1);
        this.Controls.Add(this.richTextBox1);
        this.MainMenuStrip = this.mainMenu1;
        this.Text = "RTF Document Browser";
    }

    // Bring up a dialog to open a file.
    private void openMenuItem_Click(object sender, EventArgs e)
    {
        // If a file is not opened, then set the initial directory to the
        // FolderBrowserDialog.SelectedPath value.
        if (!fileOpened) {
            openFileDialog1.InitialDirectory = folderBrowserDialog1.SelectedPath;
            openFileDialog1.FileName = null;
        }

        // Display the openFile dialog.
        DialogResult result = openFileDialog1.ShowDialog();

        // OK button was pressed.
        if (result == DialogResult.OK)
        {
            openFileName = openFileDialog1.FileName;
            try
            {
                // Output the requested file in richTextBox1.
                Stream s = openFileDialog1.OpenFile();
                richTextBox1.LoadFile(s, RichTextBoxStreamType.RichText);
                s.Close();

                fileOpened = true;
            }
            catch (Exception exp)
            {
                MessageBox.Show("An error occurred while attempting to load the file. The error is:"
                                + System.Environment.NewLine + exp.ToString() + System.Environment.NewLine);
                fileOpened = false;
            }
            Invalidate();

            closeMenuItem.Enabled = fileOpened;
        }

        // Cancel button was pressed.
        else if (result == DialogResult.Cancel)
        {
            return;
        }
    }

    // Close the current file.
    private void closeMenuItem_Click(object sender, EventArgs e)
    {
        richTextBox1.Text = "";
        fileOpened = false;

        closeMenuItem.Enabled = false;
    }

    // Bring up a dialog to choose a folder path in which to open or save a file.
    private void folderMenuItem_Click(object sender, EventArgs e)
    {
        // Show the FolderBrowserDialog.
        DialogResult result = folderBrowserDialog1.ShowDialog();
        if (result == DialogResult.OK)
        {
            folderName = folderBrowserDialog1.SelectedPath;
            if (!fileOpened)
            {
                // No file is opened, bring up openFileDialog in selected path.
                openFileDialog1.InitialDirectory = folderName;
                openFileDialog1.FileName = null;
                openMenuItem.PerformClick();
            }
        }
    }
}

' The following example displays an application that provides the ability to 
' open rich text files (rtf) into the RichTextBox. The example demonstrates 
' using the FolderBrowserDialog to set the default directory for opening files.
' The OpenFileDialog class is used to open the file.
Imports System.Drawing
Imports System.Windows.Forms
Imports System.IO

Public Class FolderBrowserDialogExampleForm 
    Inherits Form
    
    Private folderBrowserDialog1 As FolderBrowserDialog
    Private openFileDialog1 As OpenFileDialog 
    
    Private richTextBox1 As RichTextBox

    Private mainMenu1 As MainMenu
    Private fileMenuItem As MenuItem
    Private WithEvents folderMenuItem As MenuItem, _
                       closeMenuItem As MenuItem, _
                       openMenuItem As MenuItem
    
    Private openFileName As String, folderName As String

    Private fileOpened As Boolean = False

    Public Sub New()
        Me.mainMenu1 = New System.Windows.Forms.MainMenu() 
        Me.fileMenuItem = New System.Windows.Forms.MenuItem() 
        Me.openMenuItem = New System.Windows.Forms.MenuItem() 
        Me.folderMenuItem = New System.Windows.Forms.MenuItem() 
        Me.closeMenuItem = New System.Windows.Forms.MenuItem() 

        Me.openFileDialog1 = New System.Windows.Forms.OpenFileDialog() 
        Me.folderBrowserDialog1 = New System.Windows.Forms.FolderBrowserDialog() 
        Me.richTextBox1 = New System.Windows.Forms.RichTextBox() 

        Me.mainMenu1.MenuItems.Add(Me.fileMenuItem) 
        Me.fileMenuItem.MenuItems.AddRange( _
                    New System.Windows.Forms.MenuItem() {Me.openMenuItem, _
                                                         Me.closeMenuItem, _
                                                         Me.folderMenuItem}) 
        Me.fileMenuItem.Text = "File" 

        Me.openMenuItem.Text = "Open..." 

        Me.folderMenuItem.Text = "Select Directory..." 

        Me.closeMenuItem.Text = "Close" 
        Me.closeMenuItem.Enabled = False 

        Me.openFileDialog1.DefaultExt = "rtf" 
        Me.openFileDialog1.Filter = "rtf files (*.rtf)|*.rtf" 

        ' Set the Help text description for the FolderBrowserDialog.
        Me.folderBrowserDialog1.Description = _
            "Select the directory that you want to use As the default." 

        ' Do not allow the user to create New files via the FolderBrowserDialog.
        Me.folderBrowserDialog1.ShowNewFolderButton = False 

        ' Default to the My Documents folder.
        Me.folderBrowserDialog1.RootFolder = Environment.SpecialFolder.Personal 

        Me.richTextBox1.AcceptsTab = True 
        Me.richTextBox1.Location = New System.Drawing.Point(8, 8) 
        Me.richTextBox1.Size = New System.Drawing.Size(280, 344) 
        Me.richTextBox1.Anchor = AnchorStyles.Top Or AnchorStyles.Left Or _
                                 AnchorStyles.Bottom Or AnchorStyles.Right 

        Me.ClientSize = New System.Drawing.Size(296, 360) 
        Me.Controls.Add(Me.richTextBox1) 
        Me.Menu = Me.mainMenu1 
        Me.Text = "RTF Document Browser" 
    End Sub
    
    <STAThread()> _
    Shared Sub Main()
        Application.Run(New FolderBrowserDialogExampleForm())
    End Sub

    ' Bring up a dialog to open a file.
    Private Sub openMenuItem_Click(sender As object, e As System.EventArgs) _
        Handles openMenuItem.Click
        ' If a file is not opened, then set the initial directory to the
        ' FolderBrowserDialog.SelectedPath value.
        If (not fileOpened) Then
            openFileDialog1.InitialDirectory = folderBrowserDialog1.SelectedPath 
            openFileDialog1.FileName = nothing 
        End If

        ' Display the openFile dialog.
        Dim result As DialogResult = openFileDialog1.ShowDialog() 

        ' OK button was pressed.
        If (result = DialogResult.OK) Then
            openFileName = openFileDialog1.FileName 
            Try
                ' Output the requested file in richTextBox1.
                Dim s As Stream = openFileDialog1.OpenFile() 
                richTextBox1.LoadFile(s, RichTextBoxStreamType.RichText) 
                s.Close()     
            
                fileOpened = True 

            Catch exp As Exception
                MessageBox.Show("An error occurred while attempting to load the file. The error is:" _
                                + System.Environment.NewLine + exp.ToString() + System.Environment.NewLine) 
                fileOpened = False 
            End Try
            Invalidate() 

            closeMenuItem.Enabled = fileOpened 

        ' Cancel button was pressed.
        ElseIf (result = DialogResult.Cancel) Then
            return 
        End If
    End Sub

    ' Close the current file.
    Private Sub closeMenuItem_Click(sender As object, e As System.EventArgs) _
        Handles closeMenuItem.Click
        richTextBox1.Text = "" 
        fileOpened = False 

        closeMenuItem.Enabled = False 
    End Sub

    ' Bring up a dialog to chose a folder path in which to open or save a file.
    Private Sub folderMenuItem_Click(sender As object, e As System.EventArgs) _
        Handles folderMenuItem.Click
        ' Show the FolderBrowserDialog.
        Dim result As DialogResult = folderBrowserDialog1.ShowDialog() 

        If ( result = DialogResult.OK ) Then
            folderName = folderBrowserDialog1.SelectedPath 
            If (not fileOpened) Then
                ' No file is opened, bring up openFileDialog in selected path.
                openFileDialog1.InitialDirectory = folderName 
                openFileDialog1.FileName = nothing
                openMenuItem.PerformClick() 
            End If
        End If
    End Sub

End Class

Commenti

Il costruttore senza parametri inizializza le proprietà ai valori predefiniti.

Quando viene creato un nuovo FolderBrowserDialog oggetto, la RootFolder proprietà è impostata su , la Description proprietà è impostata Environment.SpecialFolder.Desktopsu una stringa vuota (""), la SelectedPath proprietà è impostata su una stringa vuota e la ShowNewFolderButton proprietà è impostata su true.

In genere, dopo aver creato un nuovo FolderBrowserDialogoggetto , è possibile impostare l'oggetto RootFolder sulla posizione da cui iniziare a esplorare. Facoltativamente, è possibile impostare il SelectedPath percorso di una sottocartella di RootFolder che verrà inizialmente selezionata. È anche possibile impostare facoltativamente la Description proprietà per fornire istruzioni aggiuntive all'utente. Infine, chiamare il ShowDialog metodo per visualizzare la finestra di dialogo all'utente. Quando la finestra di dialogo viene chiusa e il risultato della finestra di dialogo da ShowDialog è DialogResult.OK, sarà SelectedPath una stringa contenente il percorso della cartella selezionata.

FolderBrowserDialog è una finestra di dialogo modale; pertanto, quando visualizzato, blocca il resto dell'applicazione fino a quando l'utente non ha scelto una cartella. Quando viene visualizzata una finestra di dialogo modally, non può verificarsi alcun input (tastiera o clic del mouse) ad eccezione di oggetti nella finestra di dialogo. Il programma deve nascondere o chiudere la finestra di dialogo (in genere in risposta a un'azione dell'utente) prima che l'input al programma chiamante possa verificarsi.

Si applica a