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