Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

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

@@ -0,0 +1,87 @@
+//----------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+//----------------------------------------------------------------
+
+namespace System.Activities.Expressions
+{
+    using System.Activities.Statements;
+    using System.Collections.Generic;
+    using System.Linq.Expressions;
+    using System.Reflection;
+    using System.Runtime;
+    using System.Collections.ObjectModel;
+    using System.Activities.Validation;
+
+    static class MemberExpressionHelper
+    {
+        public static void AddOperandArgument<TOperand>(CodeActivityMetadata metadata, InArgument<TOperand> operand, bool isRequired)
+        {
+            RuntimeArgument operandArgument = new RuntimeArgument("Operand", typeof(TOperand), ArgumentDirection.In, isRequired);
+            metadata.Bind(operand, operandArgument);
+            metadata.AddArgument(operandArgument);
+        }
+
+        public static void AddOperandLocationArgument<TOperand>(CodeActivityMetadata metadata, InOutArgument<TOperand> operandLocation, bool isRequired)
+        {
+            RuntimeArgument operandLocationArgument = new RuntimeArgument("OperandLocation", typeof(TOperand), ArgumentDirection.InOut, isRequired);
+            metadata.Bind(operandLocation, operandLocationArgument);
+            metadata.AddArgument(operandLocationArgument);
+        }
+
+        public static bool TryGenerateLinqDelegate<TOperand, TResult>(string memberName, bool isField, bool isStatic, out Func<TOperand, TResult> operation, out ValidationError validationError)
+        {
+            operation = null;
+            validationError = null;
+
+            try
+            {
+                ParameterExpression operandParameter = Expression.Parameter(typeof(TOperand), "operand");
+                MemberExpression memberExpression = null;
+                if (isStatic)
+                {
+                    memberExpression = Expression.MakeMemberAccess(null, GetMemberInfo<TOperand>(memberName, isField));
+                }
+                else
+                {
+                    memberExpression = Expression.MakeMemberAccess(operandParameter, GetMemberInfo<TOperand>(memberName, isField));
+                }
+                Expression<Func<TOperand, TResult>> lambdaExpression = Expression.Lambda<Func<TOperand, TResult>>(memberExpression, operandParameter);
+                operation = lambdaExpression.Compile();
+                return true;
+            }
+            catch (Exception e)
+            {
+                if (Fx.IsFatal(e))
+                {
+                    throw;
+                }
+
+                validationError = new ValidationError(e.Message);
+                return false;
+            }
+        }
+
+        static MemberInfo GetMemberInfo<TOperand>(string memberName, bool isField)
+        {
+            MemberInfo result = null;
+            Type declaringType = typeof(TOperand);
+
+            if (!isField)
+            {
+                result = declaringType.GetProperty(memberName);
+            }
+            else
+            {
+                result = declaringType.GetField(memberName);
+            }
+            if (result == null)
+            {
+                throw FxTrace.Exception.AsError(new ValidationException(SR.MemberNotFound(memberName, typeof(TOperand).Name)));
+            }
+            return result;
+        }
+
+
+    }
+
+}