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//---------------------------------------------------------------------------
//
// <copyright file="CommonDialog.cs" company="Microsoft">
// Copyright (C) Microsoft Corporation. All rights reserved.
// </copyright>
//
// Description:
// CommonDialog is a base class representing common dialogs.
// At this time, we intend it only to be used as a parent class
// for the FileDialog class, although it could be used to implement
// other commdlg.dll dialogs in the future. It is not a
// general-purpose dialog class - it's specific to Win32 common
// dialogs.
//
//
// History:
// t-benja 7/7/2005 Created
//
//---------------------------------------------------------------------------
namespace Microsoft.Win32
{
using System;
using System.Runtime.InteropServices;
using System.Runtime.Remoting;
using System.Security;
using System.Security.Permissions;
using System.Threading;
using System.Windows;
using System.Windows.Interop;
using MS.Internal.Interop;
using MS.Internal.PresentationFramework;
using MS.Win32;
/// <summary>
/// An abstract base class for displaying common dialogs.
/// </summary>
/// <Remarks>
/// InheritanceDemand for UIPermission (UIPermissionWindow.AllWindows)
/// </Remarks>
/// <SecurityNote>
/// We Don't want arbitrary Partially trusted code deriving from CommonDialog.
/// InheritanceDemand for UIPermission (UIPermissionWindow.AllWindows)
/// </SecurityNote>
[UIPermission(SecurityAction.InheritanceDemand, Window = UIPermissionWindow.AllWindows)]
public abstract class CommonDialog
{
//---------------------------------------------------
//
// Constructors
//
//---------------------------------------------------
//#region Constructors
//#endregion Constructors
//---------------------------------------------------
//
// Public Methods
//
//---------------------------------------------------
#region Public Methods
/// <summary>
/// When overridden in a derived class, resets the properties
/// of a common dialog to their default values.
/// </summary>
/// <SecurityNote>
/// Critical: Changes Dialog options
/// PublicOk: This method is abstract, and there is an InheritanceDemand for
/// UIPermission (UIPermissionWindow.AllWindows) to derive from CommonDialog.
/// </SecurityNote>
[SecurityCritical]
public abstract void Reset();
/// <summary>
/// This is the public method that will be called to actually show
/// a common dialog. Since CommonDialog is abstract, this function
/// performs initialization tasks for all common dialogs and then
/// calls RunDialog.
/// </summary>
/// <Remarks>
/// Callers must have UIPermission(UIPermissionWindow.AllWindows) to call this API.
/// </Remarks>
/// <SecurityNote>
/// Critical: Calls RunDialog, and accesses parking window hwnd from Application.
/// Calls critical methods ComponentDispatcher.CriticalPushModal/CriticalPopModal.
/// PublicOk: Demands Permission appropriate to the dialog (defaults to UIPermissionWindow.AllWindows)
/// </SecurityNote>
[SecurityCritical]
public virtual Nullable<bool> ShowDialog()
{
CheckPermissionsToShowDialog();
// Don't allow file dialogs to be shown if not in interactive mode
// (for example, if we're running as a service)
if (!Environment.UserInteractive)
{
throw new InvalidOperationException(SR.Get(SRID.CantShowModalOnNonInteractive));
}
// Call GetActiveWindow to retrieve the window handle to the active window
// attached to the calling thread's message queue. We'll set the owner of
// the common dialog to this handle.
IntPtr hwndOwner = UnsafeNativeMethods.GetActiveWindow();
if (hwndOwner == IntPtr.Zero)
{
// No active window, so we'll use the parking window as the owner,
// if its available.
if (Application.Current != null)
{
hwndOwner = Application.Current.ParkingHwnd;
}
}
HwndWrapper tempParentHwnd = null;
try
{
// No active window and application wasn't available or didn't have
// a ParkingHwnd, we create a hidden parent window for the dialog to
// prevent breaking UIAutomation.
if (hwndOwner == IntPtr.Zero)
{
tempParentHwnd = new HwndWrapper(0, 0, 0, 0, 0, 0, 0, "", IntPtr.Zero, null);
hwndOwner = tempParentHwnd.Handle;
}
// Store the handle of the owner window inside our class so we can use it
// to center the dialog later.
_hwndOwnerWindow = hwndOwner;
// Signal that this thread is going to go modal.
try
{
ComponentDispatcher.CriticalPushModal();
return RunDialog(hwndOwner);
}
finally
{
ComponentDispatcher.CriticalPopModal();
}
}
finally
{
if (tempParentHwnd != null)
{
tempParentHwnd.Dispose();
}
}
}
/// <summary>
/// Runs a common dialog box, with the owner as the given Window
/// </summary>
/// <Remarks>
/// Callers must have UIPermission(UIPermissionWindow.AllWindows) to call this API.
/// </Remarks>
/// <SecurityNote>
/// Critical: Calls RunDialog and accesses owner handle and parking window hwnd from Application.
/// Calls critical methods ComponentDispatcher.CriticalPushModal/CriticalPopModal.
/// PublicOk: Demands UIPermission (UIPermissionWindow.AllWindows)
/// </SecurityNote>
[SecurityCritical]
public Nullable<bool> ShowDialog(Window owner)
{
CheckPermissionsToShowDialog();
// If a valid window wasn't passed into this function, we'll
// call ShowDialog() to use the active window instead of
// throwing an exception
if (owner == null)
{
return ShowDialog();
}
// Don't allow file dialogs to be shown if not in interactive mode
// (for example, if we're running as a service)
if (!Environment.UserInteractive)
{
throw new InvalidOperationException(SR.Get(SRID.CantShowModalOnNonInteractive));
}
// Get the handle of the owner window using WindowInteropHelper.
IntPtr hwndOwner = (new WindowInteropHelper(owner)).CriticalHandle;
// Just in case, check if the window's handle is zero.
if (hwndOwner == IntPtr.Zero)
{
// CODE
throw new InvalidOperationException();
}
// Store the handle of the owner window inside our class so we can use it
// to center the dialog later.
_hwndOwnerWindow = hwndOwner;
// Signal that this thread is going to go modal.
try
{
ComponentDispatcher.CriticalPushModal();
return RunDialog(hwndOwner);
}
finally
{
ComponentDispatcher.CriticalPopModal();
}
}
#endregion Public Methods
//---------------------------------------------------
//
// Public Properties
//
//---------------------------------------------------
#region Public Properties
/// <summary>
/// Provides the ability to attach an arbitrary object to the dialog.
/// </summary>
public object Tag
{
get
{
return _userData;
}
set
{
_userData = value;
}
}
#endregion Public Properties
//---------------------------------------------------
//
// Public Events
//
//---------------------------------------------------
//#region Public Events
//#endregion Public Events
//---------------------------------------------------
//
// Protected Methods
//
//---------------------------------------------------
#region Protected Methods
/// <summary>
/// Defines the common dialog box hook procedure that is overridden to
/// add specific functionality to a common dialog box.
/// </summary>
/// <SecurityNote>
/// Critical: Calls UnsafeNativeMethods.SetFocus() and UnsafeNativeMethods.PostMessage()
/// </SecurityNote>
[SecurityCritical]
protected virtual IntPtr HookProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam)
{
// WM_INITDIALOG
// The WM_INITDIALOG message is sent to the dialog box procedure immediately
// before a dialog box is displayed. Dialog box procedures typically use
// this message to initialize controls and carry out any other initialization
// tasks that affect the appearance of the dialog box.
//
// We handle WM_INITDIALOG to move the dialog to the center of the screen
if ((WindowMessage)msg == WindowMessage.WM_INITDIALOG)
{
// call MoveToScreenCenter to reposition the dialog based on the location
// of the owner window.
MoveToScreenCenter(new HandleRef(this,hwnd));
// WM_INITDIALOG expects TRUE to be returned to properly set focus.
return new IntPtr(1);
}
return IntPtr.Zero;
}
/// <summary>
/// When overridden in a derived class, displays a particular type of common dialog box.
/// </summary>
protected abstract bool RunDialog(IntPtr hwndOwner);
/// <summary>
/// Demands permissions appropriate to the dialog to be shown.
/// </summary>
[SecurityCritical, SecurityTreatAsSafe]
protected virtual void CheckPermissionsToShowDialog()
{
// Verify we're on the right thread.
// This mitigates multi-threaded attacks without having to make the file dialogs thread-safe.
if (_thread != Thread.CurrentThread)
{
throw new InvalidOperationException(SR.Get(SRID.CantShowOnDifferentThread));
}
SecurityHelper.DemandUIWindowPermission();
}
#endregion Protected Methods
//---------------------------------------------------
//
// Internal Methods
//
//---------------------------------------------------
#region Internal Methods
/// <summary>
/// Centers the given window on the screen. This method is used by HookProc
/// to center the dialog on the screen before it is shown. We can't mark it
/// private because we need to call it from our derived classes like
/// FileDialog.
/// </summary>
/// <SecurityNote>
/// Critical: Calls UnsafeNativeMethods.SetWindowPos()
/// </SecurityNote>
[SecurityCritical]
internal void MoveToScreenCenter(HandleRef hWnd)
{
// Create an IntPtr to store a handle to the monitor.
IntPtr hMonitor = IntPtr.Zero;
// Get the monitor to use based on the location of the parent window
if (_hwndOwnerWindow != IntPtr.Zero)
{
// we have a owner hwnd; center on the screen on
// which our owner hwnd is.
// We use MONITOR_DEFAULTTONEAREST to get the monitor
// nearest to the window if the window doesn't intersect
// any display monitor.
hMonitor = SafeNativeMethods.MonitorFromWindow(
new HandleRef(this, _hwndOwnerWindow), // window to find monitor location for
NativeMethods.MONITOR_DEFAULTTONEAREST); // get the monitor nearest to the window
// Only move the window if we got a valid monitor... otherwise let Windows
// position the dialog.
if (hMonitor != IntPtr.Zero)
{
// Now, create another RECT and fill it with the bounds of the parent window.
NativeMethods.RECT dialogRect = new NativeMethods.RECT();
SafeNativeMethods.GetWindowRect(hWnd, ref dialogRect);
Size dialogSize = new Size((dialogRect.right - dialogRect.left), /*width*/
(dialogRect.bottom - dialogRect.top)); /*height*/
// create variables that will receive the new position of the dialog
double x = 0;
double y = 0;
// Call into a static function in System.Windows.Window to calculate
// the actual new position
Window.CalculateCenterScreenPosition( hMonitor,
dialogSize,
ref x,
ref y);
// Call SetWindowPos to actually move the window.
UnsafeNativeMethods.SetWindowPos(hWnd, // handle to the window to move
NativeMethods.NullHandleRef, // window to precede this one in zorder
(int)Math.Round(x),
(int)Math.Round(y), // new X and Y positions
0, 0, // new width and height, if applicable
// Flags:
// SWP_NOSIZE: Retains current size
// SWP_NOZORDER: retains current zorder
// SWP_NOACTIVATE: does not activate the window
NativeMethods.SWP_NOSIZE | NativeMethods.SWP_NOZORDER | NativeMethods.SWP_NOACTIVATE);
}
}
}
#endregion Internal Methods
//---------------------------------------------------
//
// Internal Properties
//
//---------------------------------------------------
#region Internal Properties
#endregion Internal Properties
//---------------------------------------------------
//
// Internal Events
//
//---------------------------------------------------
//#region Internal Events
//#endregion Internal Events
//---------------------------------------------------
//
// Private Methods
//
//---------------------------------------------------
//#region Private Methods
//#endregion Private Methods
//---------------------------------------------------
//
// Protected Properties
//
//---------------------------------------------------
//#region Protected Properties
//#endregion Protected Properties
//---------------------------------------------------
//
// Private Fields
//
//---------------------------------------------------
#region Private Fields
// Private variable used to store data for the Tag property
private object _userData;
private Thread _thread = Thread.CurrentThread;
/// <summary>
/// The owner hwnd passed into the dialog is stored as a private
/// member so that the dialog can be properly centered onscreen.
/// It is exposed through the OwnerWindowHandle property.
/// </summary>
/// <SecurityNote>
/// Critical: hWnds are critical data.
/// </SecurityNote>
[SecurityCritical]
private IntPtr _hwndOwnerWindow;
#endregion Private Fields
}
}
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