Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Activities/System/Activities/Statements/While.cs

@@ -0,0 +1,152 @@
+//-----------------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+//-----------------------------------------------------------------------------
+
+namespace System.Activities.Statements
+{
+    using System.Activities.Expressions;
+    using System.Collections.ObjectModel;
+    using System.ComponentModel;
+    using System.Diagnostics.CodeAnalysis;
+    using System.Linq.Expressions;
+    using System.Runtime;
+    using System.Runtime.Collections;
+    using System.Windows.Markup;
+
+    [SuppressMessage(FxCop.Category.Naming, FxCop.Rule.IdentifiersShouldNotMatchKeywords, Justification = "Optimizing for XAML naming. VB imperative users will [] qualify (e.g. New [While])")]
+    [ContentProperty("Body")]
+    public sealed class While : NativeActivity
+    {
+        CompletionCallback onBodyComplete;
+        CompletionCallback<bool> onConditionComplete;
+
+        Collection<Variable> variables;
+
+        public While()
+            : base()
+        {
+        }
+
+        public While(Expression<Func<ActivityContext, bool>> condition)
+            : this()
+        {
+            if (condition == null)
+            {
+                throw FxTrace.Exception.ArgumentNull("condition");
+            }
+
+            this.Condition = new LambdaValue<bool>(condition);
+        }
+
+        public While(Activity<bool> condition)
+            : this()
+        {
+            if (condition == null)
+            {
+                throw FxTrace.Exception.ArgumentNull("condition");
+            }
+
+            this.Condition = condition;
+        }
+
+        public Collection<Variable> Variables
+        {
+            get
+            {
+                if (this.variables == null)
+                {
+                    this.variables = new ValidatingCollection<Variable>
+                    {
+                        // disallow null values
+                        OnAddValidationCallback = item =>
+                        {
+                            if (item == null)
+                            {
+                                throw FxTrace.Exception.ArgumentNull("item");
+                            }
+                        }
+                    };
+                }
+                return this.variables;
+            }
+        }
+
+        [DefaultValue(null)]
+        [DependsOn("Variables")]
+        public Activity<bool> Condition
+        {
+            get;
+            set;
+        }
+
+        [DefaultValue(null)]
+        [DependsOn("Condition")]
+        public Activity Body
+        {
+            get;
+            set;
+        }
+
+        protected override void OnCreateDynamicUpdateMap(DynamicUpdate.NativeActivityUpdateMapMetadata metadata, Activity originalActivity)
+        {
+            metadata.AllowUpdateInsideThisActivity();
+        }
+
+        protected override void CacheMetadata(NativeActivityMetadata metadata)
+        {
+            metadata.SetVariablesCollection(this.Variables);
+
+            metadata.AddChild(this.Body);
+
+            if (this.Condition == null)
+            {
+                metadata.AddValidationError(SR.WhileRequiresCondition(this.DisplayName));
+            }
+            else
+            {
+                metadata.AddChild(this.Condition);
+            }
+        }
+
+        protected override void Execute(NativeActivityContext context)
+        {
+            ScheduleCondition(context);
+        }
+
+        void ScheduleCondition(NativeActivityContext context)
+        {
+            Fx.Assert(this.Condition != null, "validated in OnOpen");
+            if (this.onConditionComplete == null)
+            {
+                this.onConditionComplete = new CompletionCallback<bool>(OnConditionComplete);
+            }
+
+            context.ScheduleActivity(this.Condition, this.onConditionComplete);
+        }
+
+        void OnConditionComplete(NativeActivityContext context, ActivityInstance completedInstance, bool result)
+        {
+            if (result)
+            {
+                if (this.Body != null)
+                {
+                    if (this.onBodyComplete == null)
+                    {
+                        this.onBodyComplete = new CompletionCallback(OnBodyComplete);
+                    }
+
+                    context.ScheduleActivity(this.Body, this.onBodyComplete);
+                }
+                else
+                {
+                    ScheduleCondition(context);
+                }
+            }
+        }
+
+        void OnBodyComplete(NativeActivityContext context, ActivityInstance completedInstance)
+        {
+            ScheduleCondition(context);
+        }
+    }
+}