FileDialog Class
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FileDialog Class


Displays a dialog box from which the user can select a file.

Namespace:   System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)

public abstract class FileDialog : CommonDialog


Gets or sets a value indicating whether the dialog box automatically adds an extension to a file name if the user omits the extension.


Gets or sets a value indicating whether this FileDialog instance should automatically upgrade appearance and behavior when running on Windows Vista.


Gets a value indicating whether the component can raise an event.(Inherited from Component.)


Gets or sets a value indicating whether the dialog box displays a warning if the user specifies a file name that does not exist.


Gets or sets a value indicating whether the dialog box displays a warning if the user specifies a path that does not exist.


Gets the IContainer that contains the Component.(Inherited from Component.)


Gets the custom places collection for this FileDialog instance.


Gets or sets the default file name extension.


Gets or sets a value indicating whether the dialog box returns the location of the file referenced by the shortcut or whether it returns the location of the shortcut (.lnk).


Gets a value that indicates whether the Component is currently in design mode.(Inherited from Component.)


Gets the list of event handlers that are attached to this Component.(Inherited from Component.)


Gets or sets a string containing the file name selected in the file dialog box.


Gets the file names of all selected files in the dialog box.


Gets or sets the current file name filter string, which determines the choices that appear in the "Save as file type" or "Files of type" box in the dialog box.


Gets or sets the index of the filter currently selected in the file dialog box.


Gets or sets the initial directory displayed by the file dialog box.


This API supports the product infrastructure and is not intended to be used directly from your code. Gets the Win32 instance handle for the application.


This API supports the product infrastructure and is not intended to be used directly from your code. Gets values to initialize the FileDialog.


Gets or sets a value indicating whether the dialog box restores the current directory before closing.


Gets or sets a value indicating whether the Help button is displayed in the file dialog box.


Gets or sets the ISite of the Component.(Inherited from Component.)


Gets or sets whether the dialog box supports displaying and saving files that have multiple file name extensions.


Gets or sets an object that contains data about the control. (Inherited from CommonDialog.)


Gets or sets the file dialog box title.


Gets or sets a value indicating whether the dialog box accepts only valid Win32 file names.


Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object.(Inherited from MarshalByRefObject.)


Releases all resources used by the Component.(Inherited from Component.)


Releases the unmanaged resources used by the Component and optionally releases the managed resources.(Inherited from Component.)


Determines whether the specified object is equal to the current object.(Inherited from Object.)


Releases unmanaged resources and performs other cleanup operations before the Component is reclaimed by garbage collection.(Inherited from Component.)


Serves as the default hash function. (Inherited from Object.)


Retrieves the current lifetime service object that controls the lifetime policy for this instance.(Inherited from MarshalByRefObject.)


Returns an object that represents a service provided by the Component or by its Container.(Inherited from Component.)


Gets the Type of the current instance.(Inherited from Object.)

System_CAPS_protmethodHookProc(IntPtr, Int32, IntPtr, IntPtr)

Defines the common dialog box hook procedure that is overridden to add specific functionality to the file dialog box.(Overrides CommonDialog.HookProc(IntPtr, Int32, IntPtr, IntPtr).)


Obtains a lifetime service object to control the lifetime policy for this instance.(Inherited from MarshalByRefObject.)


Creates a shallow copy of the current Object.(Inherited from Object.)


Creates a shallow copy of the current MarshalByRefObject object.(Inherited from MarshalByRefObject.)


Raises the FileOk event.


Raises the HelpRequest event.(Inherited from CommonDialog.)

System_CAPS_protmethodOwnerWndProc(IntPtr, Int32, IntPtr, IntPtr)

Defines the owner window procedure that is overridden to add specific functionality to a common dialog box.(Inherited from CommonDialog.)


Resets all properties to their default values.(Overrides CommonDialog.Reset().)


This API supports the product infrastructure and is not intended to be used directly from your code. Specifies a common dialog box.(Overrides CommonDialog.RunDialog(IntPtr).)


Runs a common dialog box with a default owner.(Inherited from CommonDialog.)


Runs a common dialog box with the specified owner.(Inherited from CommonDialog.)


This API supports the product infrastructure and is not intended to be used directly from your code. Provides a string version of this object.(Overrides Component.ToString().)


This API supports the product infrastructure and is not intended to be used directly from your code. Owns the FileOk event.


Occurs when the component is disposed by a call to the Dispose method. (Inherited from Component.)


Occurs when the user clicks on the Open or Save button on a file dialog box.


Occurs when the user clicks the Help button on a common dialog box.(Inherited from CommonDialog.)

FileDialog is an abstract class that contains common behavior for the OpenFileDialog and SaveFileDialog classes. It is not intended to be used directly but contains common behavior for those two classes. You cannot create an instance of FileDialog. Although the class is declared public, you cannot inherit from it, as it contains internal abstract methods. To create a dialog box to select or save a file, use OpenFileDialog or SaveFileDialog.

FileDialog is a modal dialog box; therefore, when shown, it blocks the rest of the application until the user has chosen a file. When a dialog box is displayed modally, no input (keyboard or mouse click) can occur except to objects on the dialog box. The program must hide or close the dialog box (usually in response to some user action) before input to the calling program can occur.


When you use classes derived from FileDialog, such as OpenFileDialog and SaveFileDialog, avoid using string literals containing absolute paths. Instead, dynamically obtain the path using one or more of the techniques described in the following table.

If you want to enable users to select a folder instead of a file, use the FolderBrowserDialog.

Depending upon the type of application, how data associated with the application is stored, and the reason for accessing the file system, there are many possible ways in which you can create a directory path. The following table shows the techniques for creating paths dynamically.

Path or program category

Class and members to use

Standard Windows paths, such as Program Files, MyDocuments, the Desktop and so on

The System.Environment class is the most complete source for these, either through its static methods, such as SystemDirectory, or through the GetFolderPath method, using one of the Environment.SpecialFolder enumerated values.

Paths related to the current application

The Application class has static members to obtain certain paths, such as StartupPath, ExecutablePath, LocalUserAppDataPath, and CommonAppDataPath.

The GetTempPath method of the System.IO.Path returns the path of the temporary folder.

The GetCurrentDirectory method of the System.IO.Directory class returns the application's current executing directory.

The RootDirectory property of the DriveInfo class represents the specified drive's root directory.

Paths stored as application settings

Access the corresponding applications settings property of the wrapper class derived from ApplicationSettingsBase. For more information, see Application Settings for Windows Forms.

Registry storage

Some applications store directory information in the registry. The Application class has the CommonAppDataPath and LocalUserAppDataPath properties that resolve to a RegistryKey value.

ClickOnce applications

For ClickOnce applications, use Application class members such as UserAppDataPath, which will return a pointer to the ClickOnce data directory. For more information, see Accessing Local and Remote Data in ClickOnce Applications.

International applications

For international applications, retrieve the relative path portion from a string resource in your application by using the System.Resources.ResourceReader class. For more information about globalization and localization, see the topic Globalizing and Localizing .NET Framework Applications.

Notice that a full path may be built up using one or more of the described techniques. For example, the GetFolderPath method might be used to obtain the path to the MyDocuments folder, then an application setting may be used to add a relative subdirectory portion.

The System.IO.Path class contains static members to assist in manipulating absolute and relative path strings, whereas the System.IO.File and System.IO.Directory classes have static members that actually manipulate files and directories, respectively.


If the user of your application changes the folder in the FileDialog, then the current working directory for your application is set to the location specified in the FileDialog. To prevent this, set the RestoreDirectory property to true.

Legacy Code Example

The following code example uses the OpenFileDialog implementation of FileDialog and illustrates creating, setting of properties, and showing the dialog box. The example uses the ShowDialog method to display the dialog box and return the DialogResult. The example requires a form with a Button placed on it and the System.IO namespace added to it.

private void button1_Click(object sender, System.EventArgs e)
    Stream myStream = null;
    OpenFileDialog openFileDialog1 = new OpenFileDialog();

    openFileDialog1.InitialDirectory = "c:\\" ;
    openFileDialog1.Filter = "txt files (*.txt)|*.txt|All files (*.*)|*.*" ;
    openFileDialog1.FilterIndex = 2 ;
    openFileDialog1.RestoreDirectory = true ;

    if(openFileDialog1.ShowDialog() == DialogResult.OK)
            if ((myStream = openFileDialog1.OpenFile()) != null)
                using (myStream)
                    // Insert code to read the stream here.
        catch (Exception ex)
            MessageBox.Show("Error: Could not read file from disk. Original error: " + ex.Message);

.NET Framework
Available since 1.1

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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