Rethrow.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 / Rethrow.cs / 1305376 / Rethrow.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// Copyright (c) Microsoft Corporation.  All rights reserved.
//-----------------------------------------------------------------------------

namespace System.Activities.Statements 
{
    using System.Activities.Runtime; 
    using System.Activities.Validation; 
    using System.Collections.Generic;
    using System.ComponentModel; 

    public sealed class Rethrow : NativeActivity
    {
        public Rethrow() 
        {
            DelegateInArgument element = new DelegateInArgument() { Name = "constraintArg" }; 
            DelegateInArgument validationContext = new DelegateInArgument() { Name = "validationContext" }; 
            base.Constraints.Add(new Constraint
            { 
                Body = new ActivityAction
                {
                    Argument1 = element,
                    Argument2 = validationContext, 
                    Handler = new RethrowBuildConstraint
                    { 
                        ParentChain = new GetParentChain 
                        {
                            ValidationContext = validationContext, 
                        },
                        RethrowActivity = element
                    },
                } 
            });
        } 
 
        protected override void CacheMetadata(NativeActivityMetadata metadata)
        { 
        }

        protected override void Execute(NativeActivityContext context)
        { 
            FaultContext faultContext = context.Properties.Find(TryCatch.FaultContextId) as FaultContext;
 
            if (faultContext == null) 
            {
                throw FxTrace.Exception.AsError(new InvalidOperationException(SR.FaultContextNotFound(this.DisplayName))); 
            }

            context.RethrowException(faultContext);
        } 

        class RethrowBuildConstraint : NativeActivity 
        { 
            [RequiredArgument]
            [DefaultValue(null)] 
            public InArgument> ParentChain
            {
                get;
                set; 
            }
 
            [RequiredArgument] 
            [DefaultValue(null)]
            public InArgument RethrowActivity 
            {
                get;
                set;
            } 

            protected override void CacheMetadata(NativeActivityMetadata metadata) 
            { 
                RuntimeArgument parentChainArgument = new RuntimeArgument("ParentChain", typeof(IEnumerable), ArgumentDirection.In, true);
                metadata.Bind(this.ParentChain, parentChainArgument); 
                metadata.AddArgument(parentChainArgument);

                RuntimeArgument rethrowActivityArgument = new RuntimeArgument("RethrowActivity", typeof(Rethrow), ArgumentDirection.In, true);
                metadata.Bind(this.RethrowActivity, rethrowActivityArgument); 
                metadata.AddArgument(rethrowActivityArgument);
            } 
 
            protected override void Execute(NativeActivityContext context)
            { 
                IEnumerable parentChain = this.ParentChain.Get(context);
                Rethrow rethrowActivity = this.RethrowActivity.Get(context);
                Activity previousActivity = rethrowActivity;
                bool privateRethrow = false; 

                // TryCatch with Rethrow is usually authored in the following way: 
                // 
                // TryCatch
                // { 
                //   Try = DoWork
                //   Catch Handler = Sequence
                //                   {
                //                     ProcessException, 
                //                     Rethrow
                //                   } 
                // } 
                // Notice that the chain of Activities is TryCatch->Sequence->Rethrow
                // We want to validate that Rethrow is in the catch block of TryCatch 
                // We walk up the parent chain until we find TryCatch.  Then we check if one the catch handlers points to Sequence(the previous activity in the tree)
                foreach (Activity parent in parentChain)
                {
                    // Rethrow is only allowed under the public children of a TryCatch activity. 
                    // If any of the activities in the tree is a private child, report a constraint violation.
                    if (parent.ImplementationChildren.Contains(previousActivity)) 
                    { 
                        privateRethrow = true;
                    } 

                    TryCatch tryCatch = parent as TryCatch;
                    if(tryCatch != null)
                    { 
                        if (previousActivity != null)
                        { 
                            foreach (Catch catchHandler in tryCatch.Catches) 
                            {
                                ActivityDelegate catchAction = catchHandler.GetAction(); 
                                if (catchAction != null && catchAction.Handler == previousActivity)
                                {
                                    if (privateRethrow)
                                    { 
                                        Constraint.AddValidationError(context, new ValidationError(SR.RethrowMustBeAPublicChild(rethrowActivity.DisplayName), rethrowActivity));
                                    } 
                                    return; 
                                }
                            } 
                        }
                    }

                    previousActivity = parent; 
                }
 
                Constraint.AddValidationError(context, new ValidationError(SR.RethrowNotInATryCatch(rethrowActivity.DisplayName), rethrowActivity)); 
            }
        } 
    }
}


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

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