DispatcherFrame.cs source code in C# .NET

Source code for the .NET framework in C#

                        

Code:

/ Dotnetfx_Win7_3.5.1 / Dotnetfx_Win7_3.5.1 / 3.5.1 / DEVDIV / depot / DevDiv / releases / Orcas / NetFXw7 / wpf / src / Base / System / Windows / Threading / DispatcherFrame.cs / 1 / DispatcherFrame.cs

                            using System; 
using System.Security;

namespace System.Windows.Threading
{ 
    /// 
    ///     Representation of Dispatcher frame. 
    ///  
    public class DispatcherFrame : DispatcherObject
    { 

        /// 
        ///     Critical: This code exists to ensure that the static variables initialized
        ///     do not cause security violations.The reason this comes into existance is because 
        ///     of the call to RegisterWindowMessage
        ///     TreatAsSafe:This is safe to call 
        ///  
        [SecurityCritical,SecurityTreatAsSafe]
        static DispatcherFrame() 
        {
        }

        ///  
        ///     Constructs a new instance of the DispatcherFrame class.
        ///  
        public DispatcherFrame() : this(true) 
        {
        } 

        /// 
        ///     Constructs a new instance of the DispatcherFrame class.
        ///  
        /// 
        ///     Indicates whether or not this frame will exit when all frames 
        ///     are requested to exit. 
        ///     

/// Dispatcher frames typically break down into two categories: /// 1) Long running, general purpose frames, that exit only when /// told to. These frames should exit when requested. /// 2) Short running, very specific frames that exit themselves /// when an important criteria is met. These frames may /// consider not exiting when requested in favor of waiting /// for their important criteria to be met. These frames /// should have a timeout associated with them. /// public DispatcherFrame(bool exitWhenRequested) { _exitWhenRequested = exitWhenRequested; _continue = true; } ///

/// Indicates that this dispatcher frame should exit. /// /// /// Critical - calls a critical method - postThreadMessage. /// PublicOK - all we're doing is posting a current message to our thread. /// net effect is the dispatcher "wakes up" /// and uses the continue flag ( which may have just changed). /// public bool Continue { get { // This method is free-threaded. // First check if this frame wants to continue. bool shouldContinue = _continue; if(shouldContinue) { // This frame wants to continue, so next check if it will // respect the "exit requests" from the dispatcher. if(_exitWhenRequested) { Dispatcher dispatcher = Dispatcher; // This frame is willing to respect the "exit requests" of // the dispatcher, so check them. if(dispatcher._exitAllFrames || dispatcher._hasShutdownStarted) { shouldContinue = false; } } } return shouldContinue; } [SecurityCritical] set { // This method is free-threaded. _continue = value; // Post a message so that the message pump will wake up and // check our continue state. Dispatcher.BeginInvoke(DispatcherPriority.Send, (DispatcherOperationCallback) delegate(object unused) {return null;}, null); } } private bool _exitWhenRequested; private bool _continue; } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. // Copyright (c) Microsoft Corporation. All rights reserved. using System; using System.Security; namespace System.Windows.Threading { /// /// Representation of Dispatcher frame. /// public class DispatcherFrame : DispatcherObject { /// /// Critical: This code exists to ensure that the static variables initialized /// do not cause security violations.The reason this comes into existance is because /// of the call to RegisterWindowMessage /// TreatAsSafe:This is safe to call /// [SecurityCritical,SecurityTreatAsSafe] static DispatcherFrame() { } /// /// Constructs a new instance of the DispatcherFrame class. /// public DispatcherFrame() : this(true) { } /// /// Constructs a new instance of the DispatcherFrame class. /// /// /// Indicates whether or not this frame will exit when all frames /// are requested to exit. ///

/// Dispatcher frames typically break down into two categories: /// 1) Long running, general purpose frames, that exit only when /// told to. These frames should exit when requested. /// 2) Short running, very specific frames that exit themselves /// when an important criteria is met. These frames may /// consider not exiting when requested in favor of waiting /// for their important criteria to be met. These frames /// should have a timeout associated with them. /// public DispatcherFrame(bool exitWhenRequested) { _exitWhenRequested = exitWhenRequested; _continue = true; } ///

/// Indicates that this dispatcher frame should exit. /// /// /// Critical - calls a critical method - postThreadMessage. /// PublicOK - all we're doing is posting a current message to our thread. /// net effect is the dispatcher "wakes up" /// and uses the continue flag ( which may have just changed). /// public bool Continue { get { // This method is free-threaded. // First check if this frame wants to continue. bool shouldContinue = _continue; if(shouldContinue) { // This frame wants to continue, so next check if it will // respect the "exit requests" from the dispatcher. if(_exitWhenRequested) { Dispatcher dispatcher = Dispatcher; // This frame is willing to respect the "exit requests" of // the dispatcher, so check them. if(dispatcher._exitAllFrames || dispatcher._hasShutdownStarted) { shouldContinue = false; } } } return shouldContinue; } [SecurityCritical] set { // This method is free-threaded. _continue = value; // Post a message so that the message pump will wake up and // check our continue state. Dispatcher.BeginInvoke(DispatcherPriority.Send, (DispatcherOperationCallback) delegate(object unused) {return null;}, null); } } private bool _exitWhenRequested; private bool _continue; } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. // Copyright (c) Microsoft Corporation. All rights reserved.

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