Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

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

@@ -0,0 +1,69 @@
+//-----------------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+//-----------------------------------------------------------------------------
+
+namespace System.Activities.Expressions
+{
+    using System.Linq.Expressions;
+    using System.Runtime;
+
+    public sealed class VariableValue<T> : EnvironmentLocationValue<T>
+    {
+        public VariableValue()
+            : base()
+        {
+        }
+
+        public VariableValue(Variable variable)
+            : base()
+        {
+            this.Variable = variable;
+        }
+
+        public Variable Variable
+        {
+            get;
+            set;
+        }
+
+        public override LocationReference LocationReference
+        {
+            get { return this.Variable; }
+        }
+
+        protected override void CacheMetadata(CodeActivityMetadata metadata)
+        {
+            if (this.Variable == null)
+            {
+                metadata.AddValidationError(SR.VariableMustBeSet);
+            }
+            else
+            {
+                if (!(this.Variable is Variable<T>) && !TypeHelper.AreTypesCompatible(this.Variable.Type, typeof(T)))
+                {
+                    metadata.AddValidationError(SR.VariableTypeInvalid(this.Variable, typeof(T), this.Variable.Type));
+                }
+
+                if (!this.Variable.IsInTree)
+                {
+                    metadata.AddValidationError(SR.VariableShouldBeOpen(this.Variable.Name));
+                }
+
+                if (!metadata.Environment.IsVisible(this.Variable))
+                {
+                    metadata.AddValidationError(SR.VariableNotVisible(this.Variable.Name));
+                }
+            }
+        }
+
+        public override string ToString()
+        {
+            if (Variable != null && !string.IsNullOrEmpty(Variable.Name))
+            {
+                return Variable.Name;
+            }
+
+            return base.ToString();
+        }
+    }
+}