FilePresentation.cs source code in C# .NET

                        Code:
                         / DotNET / DotNET / 8.0 / untmp / WIN_WINDOWS / lh_tools_devdiv_wpf / Windows / wcp / TrustUi / MS / Internal / documents / Application / FilePresentation.cs / 1 / FilePresentation.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// 
//    Copyright (C) Microsoft Corporation.  All rights reserved. 
//
//  
//  Interacts with user on file based information for XpsViewer.
//  
// 
// History:
//  08/28/2005: [....]: Refactored some of the code from FileManagement.cs 
//                        Simplified responsiblity to user interaction
//-----------------------------------------------------------------------------

using System; 
using System.IO;
using System.Security; 
using System.Security.Permissions; 
using System.Windows.Forms;
using System.Windows.TrustUI; 

namespace MS.Internal.Documents.Application
{
///  
/// Interacts with user on file based information for XpsViewer.
///  
///  
/// Responsibility:
/// Should be the only class that interacts with the user with or for file 
/// location information.
/// 
internal static class FilePresentation
{ 
    #region Internal Methods
    //------------------------------------------------------------------------- 
    // Internal Methods 
    //-------------------------------------------------------------------------
 
    /// 
    /// Prompts the user for the save location for the current XpsDocument.
    /// 
    /// The token for the current document 
    /// 
    ///  
    /// Critical: 
    ///  - we access and set CriticalFileToken
    ///  - we create a CriticalFileToken for the user specifed location 
    ///  - we access the RootBrowserWindow, which is critical
    ///  - we assert to show the file save dialog
    ///  - we make asserts to get the local filename specified by the
    ///    the user; the file name is not stored 
    /// TreatAsSafe:
    ///  - the caller has the fileToken for the existing document 
    ///  - the data already exists on the system we are simply updating it 
    ///    with information provided by the user
    ///  - the data is data the user already had access to 
    ///  - document is an XpsDocument a non executable extension that is
    ///    safe to run in PartialTrust
    /// 
    [SecurityCritical, SecurityTreatAsSafe] 
    internal static bool ShowSaveFileDialog(ref CriticalFileToken fileToken)
    { 
        string extension = SR.Get(SRID.FileManagementSaveExt); 

        Trace.SafeWrite(Trace.File, "Showing SafeFileDialog."); 

        bool result = false;

        SaveFileDialog save = new SaveFileDialog(); 

        if (fileToken != null) 
        { 
            string originalLocation = fileToken.Location.LocalPath;
            new FileIOPermission(PermissionState.Unrestricted).Assert(); // BlessedAssert 
            try
            {
                save.FileName = originalLocation;
            } 
            finally
            { 
                FileIOPermission.RevertAssert(); 
            }
        } 

        save.Filter = SR.Get(SRID.FileManagementSaveFilter);
        save.DefaultExt = extension;
 
        DialogResult dialogResult;
 
        // We need FileDialogPermissionAccess.Save and UIPermission.AllWindows 
        // to invoke the ShowDialog method specifying a parent window.
        // We need to specify a parent window in order to avoid a Winforms 
        // Common Dialog issue where the wrong window is used as the parent
        // which causes the Save dialog to be incorrectly localized.
        PermissionSet permissions = new PermissionSet(PermissionState.None);
        permissions.AddPermission(new UIPermission(UIPermissionWindow.AllWindows)); 
        permissions.AddPermission(new FileDialogPermission(FileDialogPermissionAccess.Save));
 
        // Get the root browser window, if it exists. 
        IWin32Window rbw = null;
        if (DocumentApplicationDocumentViewer.Instance != null) 
        {
            rbw = DocumentApplicationDocumentViewer.Instance.RootBrowserWindow;
        }
 
        permissions.Assert(); //BlessedAssert
        try 
        { 
            if (rbw != null)
            { 
                dialogResult = save.ShowDialog(rbw);
            }
            else
            { 
                dialogResult = save.ShowDialog();
            } 
        } 
        finally
        { 
            PermissionSet.RevertAssert();
        }

        if (dialogResult == DialogResult.OK) 
        {
            string filePath; 
            // can not use OpenFile w/ stream as we need the name 
            // to do a safe save as word does
            FileIOPermission getFileName = new FileIOPermission(PermissionState.None); 
            // path is unknown at this time
            // get_FileName requires AllAccess; wish it was PathDiscovery imho
            getFileName.AllFiles = FileIOPermissionAccess.AllAccess;
 
            getFileName.Assert(); //BlessedAssert
            try 
            { 
                filePath = save.FileName;
            } 
            finally
            {
                FileIOPermission.RevertAssert();
            } 

            // Add .xps extension if not already present. 
            // This must be done manually since the file save dialog will automatically 
            // add the extension only if the filename doesn't have a known extension.
            // For instance, homework.1 would become homework.1.xps, but if the user 
            // gets up to homework.386, then the dialog would just pass it through as
            // is, requiring us to append the extension here.
            if (!extension.Equals(
                Path.GetExtension(filePath), 
                StringComparison.OrdinalIgnoreCase))
            { 
                filePath = filePath + extension; 
            }
 
            Uri file = new Uri(filePath);

            // as this is the only place we can verify the user authorized this
            // particular file we construct the token here 
            new FileIOPermission(
                FileIOPermissionAccess.Read | FileIOPermissionAccess.Write, 
                filePath) 
            .Assert(); // BlessedAssert
            try 
            {
                fileToken = new CriticalFileToken(file);
            }
            finally 
            {
                FileIOPermission.RevertAssert(); 
            } 
            result = true;
            Trace.SafeWrite(Trace.File, "A save location was selected."); 
        }

        return result;
    } 

    ///  
    /// Notifies the user that the selected destination file is read-only, so 
    /// we cannot save to that location.
    ///  
    internal static void ShowDestinationIsReadOnly()
    {
        System.Windows.MessageBox.Show(
            SR.Get(SRID.FileManagementDestinationIsReadOnly), 
            SR.Get(SRID.FileManagementTitleError),
            System.Windows.MessageBoxButton.OK, 
            System.Windows.MessageBoxImage.Exclamation 
            );
    } 

    /// 
    /// Notifies the user of the failure to create temporary files, which
    /// prevents editing. 
    /// 
    internal static void ShowNoTemporaryFileAccess() 
    { 
        System.Windows.MessageBox.Show(
            SR.Get(SRID.FileManagementNoTemporaryFileAccess), 
            SR.Get(SRID.FileManagementTitleError),
            System.Windows.MessageBoxButton.OK,
            System.Windows.MessageBoxImage.Exclamation
            ); 
    }
 
    ///  
    /// Notifies the user of the failure to open from a location.
    ///  
    internal static void ShowNoAccessToSource()
    {
        System.Windows.MessageBox.Show(
            SR.Get(SRID.FileManagementNoAccessToSource), 
            SR.Get(SRID.FileManagementTitleError),
            System.Windows.MessageBoxButton.OK, 
            System.Windows.MessageBoxImage.Exclamation 
            );
    } 

    /// 
    /// Notifies the user of the failure to save to a location.
    ///  
    internal static void ShowNoAccessToDestination()
    { 
        System.Windows.MessageBox.Show( 
            SR.Get(SRID.FileManagementNoAccessToDestination),
            SR.Get(SRID.FileManagementTitleError), 
            System.Windows.MessageBoxButton.OK,
            System.Windows.MessageBoxImage.Exclamation
            );
    } 
    #endregion Internal Methods
} 
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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