AsyncOperation.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / FX-1434 / FX-1434 / 1.0 / untmp / whidbey / REDBITS / ndp / fx / src / CompMod / System / ComponentModel / AsyncOperation.cs / 1 / AsyncOperation.cs
                        

                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

namespace System.ComponentModel 
{ 
    using System.Security.Permissions;
    using System.Threading; 

    [HostProtection(SharedState = true)]
    public sealed class AsyncOperation
    { 
        private SynchronizationContext syncContext;
        private object userSuppliedState; 
        private bool alreadyCompleted; 

        ///  
        ///     Constructor. Protected to avoid unwitting usage - AsyncOperation objects
        ///     are typically created by AsyncOperationManager calling CreateOperation.
        /// 
        private AsyncOperation(object userSuppliedState, SynchronizationContext syncContext) 
        {
            this.userSuppliedState = userSuppliedState; 
            this.syncContext = syncContext; 
            this.alreadyCompleted = false;
            this.syncContext.OperationStarted(); 
        }

        /// 
        ///     Destructor. Guarantees that sync context will always get notified of completion. 
        /// 
        ~AsyncOperation() 
        { 
            if (!alreadyCompleted && syncContext != null)
            { 
                syncContext.OperationCompleted();
            }
        }
 
        public object UserSuppliedState
        { 
            get { return userSuppliedState; } 
        }
 
        /// 
        public SynchronizationContext SynchronizationContext
        {
            get 
            {
                return syncContext; 
            } 
        }
 
        public void Post(SendOrPostCallback d, object arg)
        {
            VerifyNotCompleted();
            VerifyDelegateNotNull(d); 
            syncContext.Post(d, arg);
        } 
 
        public void PostOperationCompleted(SendOrPostCallback d, object arg)
        { 
            Post(d, arg);
            OperationCompletedCore();
        }
 
        public void OperationCompleted()
        { 
            VerifyNotCompleted(); 
            OperationCompletedCore();
        } 

        private void OperationCompletedCore()
        {
            try 
            {
                syncContext.OperationCompleted(); 
            } 
            finally
            { 
                alreadyCompleted = true;
                GC.SuppressFinalize(this);
            }
        } 

        private void VerifyNotCompleted() 
        { 
            if (alreadyCompleted)
            { 
                throw new InvalidOperationException(SR.GetString(SR.Async_OperationAlreadyCompleted));
            }
        }
 
        private void VerifyDelegateNotNull(SendOrPostCallback d)
        { 
            if (d == null) 
            {
                throw new ArgumentNullException(SR.GetString(SR.Async_NullDelegate), "d"); 
            }
        }

        ///  
        ///     Only for use by AsyncOperationManager to create new AsyncOperation objects
        ///  
        internal static AsyncOperation CreateOperation(object userSuppliedState, SynchronizationContext syncContext) 
        {
            AsyncOperation newOp = new AsyncOperation(userSuppliedState, syncContext); 
            return newOp;
        }
    }
}

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