Code:
/ 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / cdf / src / NetFx40 / System.Activities / System / Activities / Statements / TryCatch.cs / 1305376 / TryCatch.cs
//------------------------------------------------------------------------------ // Copyright (c) Microsoft Corporation. All rights reserved. //----------------------------------------------------------------------------- namespace System.Activities.Statements { using System; using System.Activities; using System.Activities.Runtime; using System.Collections.Generic; using System.Collections.ObjectModel; using System.ComponentModel; using System.Runtime.Collections; using System.Runtime.Serialization; using System.Windows.Markup; public sealed class TryCatch : NativeActivity { CatchList catches; Collectionvariables; Variable state; FaultCallback exceptionFromCatchOrFinallyHandler; internal const string FaultContextId = "{35ABC8C3-9AF1-4426-8293-A6DDBB6ED91D}"; public TryCatch() : base() { this.state = new Variable (); } 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 Try { get; set; } [DependsOn("Try")] public Collection Catches { get { if (this.catches == null) { this.catches = new CatchList(); } return this.catches; } } [DefaultValue(null)] [DependsOn("Catches")] public Activity Finally { get; set; } FaultCallback ExceptionFromCatchOrFinallyHandler { get { if (this.exceptionFromCatchOrFinallyHandler == null) { this.exceptionFromCatchOrFinallyHandler = new FaultCallback(OnExceptionFromCatchOrFinally); } return this.exceptionFromCatchOrFinallyHandler; } } protected override void CacheMetadata(NativeActivityMetadata metadata) { if (Try != null) { metadata.AddChild(this.Try); } if (this.Finally != null) { metadata.AddChild(this.Finally); } Collection delegates = new Collection (); if (this.catches != null) { foreach (Catch item in this.catches) { ActivityDelegate catchDelegate = item.GetAction(); if (catchDelegate != null) { delegates.Add(catchDelegate); } } } metadata.AddImplementationVariable(this.state); metadata.SetDelegatesCollection(delegates); metadata.SetVariablesCollection(this.Variables); if (this.Finally == null && this.Catches.Count == 0) { metadata.AddValidationError(SR.CatchOrFinallyExpected(this.DisplayName)); } } internal static Catch FindCatchActivity(Type typeToMatch, IList catches) { foreach (Catch item in catches) { if (item.ExceptionType == typeToMatch) { return item; } } return null; } protected override void Execute(NativeActivityContext context) { this.state.Set(context, new TryCatchState()); if (this.Try != null) { context.ScheduleActivity(this.Try, new CompletionCallback(OnTryComplete), new FaultCallback(OnExceptionFromTry)); } else { OnTryComplete(context, null); } } protected override void Cancel(NativeActivityContext context) { TryCatchState state = this.state.Get(context); if (!state.SuppressCancel) { context.CancelChildren(); } } void OnTryComplete(NativeActivityContext context, ActivityInstance completedInstance) { TryCatchState state = this.state.Get(context); // We only allow the Try to be canceled. state.SuppressCancel = true; if (state.CaughtException != null) { Catch toSchedule = FindCatch(state.CaughtException.Exception); if (toSchedule != null) { state.ExceptionHandled = true; if (toSchedule.GetAction() != null) { context.Properties.Add(FaultContextId, state.CaughtException, true); toSchedule.ScheduleAction(context, state.CaughtException.Exception, new CompletionCallback(OnCatchComplete), this.ExceptionFromCatchOrFinallyHandler); return; } } } OnCatchComplete(context, null); } void OnExceptionFromTry(NativeActivityFaultContext context, Exception propagatedException, ActivityInstance propagatedFrom) { if(propagatedFrom.IsCancellationRequested) { if (TD.TryCatchExceptionDuringCancelationIsEnabled()) { TD.TryCatchExceptionDuringCancelation(this.DisplayName); } // The Try activity threw an exception during Cancel; abort the workflow context.Abort(propagatedException); context.HandleFault(); } else { Catch catchHandler = FindCatch(propagatedException); if (catchHandler != null) { if (TD.TryCatchExceptionFromTryIsEnabled()) { TD.TryCatchExceptionFromTry(this.DisplayName, propagatedException.GetType().ToString()); } context.CancelChild(propagatedFrom); TryCatchState state = this.state.Get(context); state.CaughtException = context.CreateFaultContext(); context.HandleFault(); } } } void OnCatchComplete(NativeActivityContext context, ActivityInstance completedInstance) { // Start suppressing cancel for the finally activity TryCatchState state = this.state.Get(context); state.SuppressCancel = true; if (completedInstance != null && completedInstance.State != ActivityInstanceState.Closed) { state.ExceptionHandled = false; } context.Properties.Remove(FaultContextId); if (this.Finally != null) { context.ScheduleActivity(this.Finally, new CompletionCallback(OnFinallyComplete), this.ExceptionFromCatchOrFinallyHandler); } else { OnFinallyComplete(context, null); } } void OnFinallyComplete(NativeActivityContext context, ActivityInstance completedInstance) { TryCatchState state = this.state.Get(context); if (context.IsCancellationRequested && !state.ExceptionHandled) { context.MarkCanceled(); } } void OnExceptionFromCatchOrFinally(NativeActivityFaultContext context, Exception propagatedException, ActivityInstance propagatedFrom) { if (TD.TryCatchExceptionFromCatchOrFinallyIsEnabled()) { TD.TryCatchExceptionFromCatchOrFinally(this.DisplayName); } // We allow cancel through if there is an exception from the catch or finally TryCatchState state = this.state.Get(context); state.SuppressCancel = false; } Catch FindCatch(Exception exception) { Type exceptionType = exception.GetType(); Catch potentialCatch = null; foreach (Catch catchHandler in this.Catches) { if (catchHandler.ExceptionType == exceptionType) { // An exact match return catchHandler; } else if (catchHandler.ExceptionType.IsAssignableFrom(exceptionType)) { if (potentialCatch != null) { if (catchHandler.ExceptionType.IsSubclassOf(potentialCatch.ExceptionType)) { // The new handler is more specific potentialCatch = catchHandler; } } else { potentialCatch = catchHandler; } } } return potentialCatch; } [DataContract] internal class TryCatchState { [DataMember(EmitDefaultValue = false)] public bool SuppressCancel { get; set; } [DataMember(EmitDefaultValue = false)] public FaultContext CaughtException { get; set; } [DataMember(EmitDefaultValue = false)] public bool ExceptionHandled { get; set; } } class CatchList : ValidatingCollection { public CatchList() : base() { this.OnAddValidationCallback = item => { if (item == null) { throw FxTrace.Exception.ArgumentNull("item"); } }; } protected override void InsertItem(int index, Catch item) { if (item == null) { throw FxTrace.Exception.ArgumentNull("item"); } Catch existingCatch = TryCatch.FindCatchActivity(item.ExceptionType, this.Items); if (existingCatch != null) { throw FxTrace.Exception.Argument("item", SR.DuplicateCatchClause(item.ExceptionType.FullName)); } base.InsertItem(index, item); } protected override void SetItem(int index, Catch item) { if (item == null) { throw FxTrace.Exception.ArgumentNull("item"); } Catch existingCatch = TryCatch.FindCatchActivity(item.ExceptionType, this.Items); if (existingCatch != null && !object.ReferenceEquals(this[index], existingCatch)) { throw FxTrace.Exception.Argument("item", SR.DuplicateCatchClause(item.ExceptionType.FullName)); } base.SetItem(index, item); } } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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