Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Activities/System/Activities/Expressions/OrElse.cs

@@ -0,0 +1,82 @@
+//----------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+//----------------------------------------------------------------
+
+namespace System.Activities.Expressions
+{
+    using System.Activities;
+    using System.Activities.DynamicUpdate;
+    using System.Activities.Statements;
+    using System.ComponentModel;
+    using System.Diagnostics.CodeAnalysis;
+    using System.Runtime;
+
+    [SuppressMessage(FxCop.Category.Naming, FxCop.Rule.IdentifiersShouldNotMatchKeywords, Justification = "Optimizing for XAML naming. VB imperative users will [] qualify (e.g. New [OrElse])")]
+    public sealed class OrElse : Activity<bool>
+    {
+        public OrElse()
+            : base()
+        {
+            this.Implementation =
+                () =>
+                {
+                    if (this.Left != null && this.Right != null)
+                    {
+                        return new If
+                        {
+                            Condition = this.Left,
+                            Then = new Assign<bool>
+                            {
+                                To = new OutArgument<bool>(context => this.Result.Get(context)),
+                                Value = true,
+                            },
+                            Else = new Assign<bool>
+                            {
+                                To = new OutArgument<bool>(context => this.Result.Get(context)),
+                                Value = new InArgument<bool>(this.Right)
+                            }
+                        };
+                    }
+                    else
+                    {
+                        return null;
+                    }
+                };
+        }
+
+        [DefaultValue(null)]
+        public Activity<bool> Left
+        {
+            get;
+            set;
+        }
+
+        [DefaultValue(null)]
+        public Activity<bool> Right
+        {
+            get;
+            set;
+        }
+
+        protected override void OnCreateDynamicUpdateMap(UpdateMapMetadata metadata, Activity originalActivity)
+        {
+            metadata.AllowUpdateInsideThisActivity();
+        }
+
+        protected override void CacheMetadata(ActivityMetadata metadata)
+        {
+            metadata.AddImportedChild(this.Left);
+            metadata.AddImportedChild(this.Right);
+
+            if (this.Left == null)
+            {
+                metadata.AddValidationError(SR.BinaryExpressionActivityRequiresArgument("Left", "OrElse", this.DisplayName));
+            }
+
+            if (this.Right == null)
+            {
+                metadata.AddValidationError(SR.BinaryExpressionActivityRequiresArgument("Right", "OrElse", this.DisplayName));
+            }
+        }
+    }
+}