Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

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

@@ -0,0 +1,69 @@
+//-----------------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+//-----------------------------------------------------------------------------
+
+namespace System.Activities.Expressions
+{
+    using System.Collections.Generic;
+    using System.Linq.Expressions;
+    using System.Runtime;
+    using System.Windows.Markup;
+
+    public sealed class ArgumentReference<T> : EnvironmentLocationReference<T>
+    {
+        RuntimeArgument targetArgument;
+
+        public ArgumentReference()
+        {
+        }
+
+        public ArgumentReference(string argumentName)
+        {
+            this.ArgumentName = argumentName;
+        }
+
+        public string ArgumentName
+        {
+            get;
+            set;
+        }
+
+        public override LocationReference LocationReference
+        {
+            get { return this.targetArgument; }
+        }
+
+        protected override void CacheMetadata(CodeActivityMetadata metadata)
+        {
+            this.targetArgument = null;
+
+            if (string.IsNullOrEmpty(this.ArgumentName))
+            {
+                metadata.AddValidationError(SR.ArgumentNameRequired);
+            }
+            else
+            {
+                this.targetArgument = ActivityUtilities.FindArgument(this.ArgumentName, this);
+
+                if (this.targetArgument == null)
+                {
+                    metadata.AddValidationError(SR.ArgumentNotFound(this.ArgumentName));
+                }
+                else if (this.targetArgument.Type != typeof(T))
+                {
+                    metadata.AddValidationError(SR.ArgumentTypeMustBeCompatible(this.ArgumentName, this.targetArgument.Type, typeof(T)));
+                }
+            }
+        }
+
+        public override string ToString()
+        {
+            if (!string.IsNullOrEmpty(this.ArgumentName))
+            {
+                return this.ArgumentName;
+            }
+
+            return base.ToString();
+        }
+    }
+}