Parallel.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / cdf / src / NetFx40 / System.Activities / System / Activities / Statements / Parallel.cs / 1305376 / Parallel.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// Copyright (c) Microsoft Corporation.  All rights reserved.
//-----------------------------------------------------------------------------

namespace System.Activities.Statements 
{
    using System.Activities; 
    using System.Activities.Validation; 
    using System.Collections.Generic;
    using System.Collections.ObjectModel; 
    using System.ComponentModel;
    using System.Windows.Markup;
    using System.Runtime.Collections;
 
    [ContentProperty("Branches")]
    public sealed class Parallel : NativeActivity 
    { 
        CompletionCallback onConditionComplete;
        Collection branches; 
        Collection variables;

        Variable hasCompleted;
 
        public Parallel()
            : base() 
        { 
        }
 
        public Collection Variables
        {
            get
            { 
                if (this.variables == null)
                { 
                    this.variables = new ValidatingCollection 
                    {
                        // disallow null values 
                        OnAddValidationCallback = item =>
                        {
                            if (item == null)
                            { 
                                throw FxTrace.Exception.ArgumentNull("item");
                            } 
                        } 
                    };
                } 
                return this.variables;
            }
        }
 
        [DefaultValue(null)]
        [DependsOn("Variables")] 
        public Activity CompletionCondition 
        {
            get; 
            set;
        }

        [DependsOn("CompletionCondition")] 
        public Collection Branches
        { 
            get 
            {
                if (this.branches == null) 
                {
                    this.branches = new ValidatingCollection
                    {
                        // disallow null values 
                        OnAddValidationCallback = item =>
                        { 
                            if (item == null) 
                            {
                                throw FxTrace.Exception.ArgumentNull("item"); 
                            }
                        }
                    };
                } 
                return this.branches;
            } 
        } 

        protected override void CacheMetadata(NativeActivityMetadata metadata) 
        {
            Collection children = new Collection();

            foreach (Activity branch in this.Branches) 
            {
                children.Add(branch); 
            } 

            if (this.CompletionCondition != null) 
            {
                children.Add(this.CompletionCondition);
            }
 
            metadata.SetChildrenCollection(children);
 
            metadata.SetVariablesCollection(this.Variables); 

            if (this.CompletionCondition != null) 
            {
                if (this.hasCompleted == null)
                {
                    this.hasCompleted = new Variable(); 
                }
 
                metadata.AddImplementationVariable(this.hasCompleted); 
            }
        } 
        protected override void Execute(NativeActivityContext context)
        {
            if (this.branches != null && this.Branches.Count != 0)
            { 
                CompletionCallback onBranchComplete = new CompletionCallback(OnBranchComplete);
 
                for (int i = this.Branches.Count - 1; i >= 0; i--) 
                {
                    context.ScheduleActivity(this.Branches[i], onBranchComplete); 
                }
            }
        }
 
        protected override void Cancel(NativeActivityContext context)
        { 
            // If we don't have a completion condition then we can just 
            // use default logic.
            if (this.CompletionCondition == null) 
            {
                base.Cancel(context);
            }
            else 
            {
                context.CancelChildren(); 
            } 
        }
 
        void OnBranchComplete(NativeActivityContext context, ActivityInstance completedInstance)
        {
            if (this.CompletionCondition != null && !this.hasCompleted.Get(context))
            { 
                // If we haven't completed, we've been requested to cancel, and we've had a child
                // end in a non-Closed state then we should cancel ourselves. 
                if (completedInstance.State != ActivityInstanceState.Closed && context.IsCancellationRequested) 
                {
                    context.MarkCanceled(); 
                    this.hasCompleted.Set(context, true);
                    return;
                }
 
                if (this.onConditionComplete == null)
                { 
                    this.onConditionComplete = new CompletionCallback(OnConditionComplete); 
                }
 
                context.ScheduleActivity(this.CompletionCondition, this.onConditionComplete);
            }
        }
 
        void OnConditionComplete(NativeActivityContext context, ActivityInstance completedInstance, bool result)
        { 
            if (result) 
            {
                context.CancelChildren(); 
                this.hasCompleted.Set(context, true);
            }
        }
    } 
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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Parallel.cs source code in C# .NET

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