92 lines
3.3 KiB
C#
92 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;
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using System.Activities.Validation;
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using System.ComponentModel;
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using System.Reflection;
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using System.Runtime;
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public sealed class PropertyValue<TOperand, TResult> : CodeActivity<TResult>
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{
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Func<TOperand, TResult> operationFunction;
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bool isOperationFunctionStatic;
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public InArgument<TOperand> Operand
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{
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get;
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set;
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}
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[DefaultValue(null)]
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public string PropertyName
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{
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get;
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set;
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}
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protected override void CacheMetadata(CodeActivityMetadata metadata)
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{
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bool isRequired = false;
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if (typeof(TOperand).IsEnum)
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{
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metadata.AddValidationError(SR.TargetTypeCannotBeEnum(this.GetType().Name, this.DisplayName));
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}
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if (string.IsNullOrEmpty(this.PropertyName))
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{
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metadata.AddValidationError(SR.ActivityPropertyMustBeSet("PropertyName", this.DisplayName));
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}
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else
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{
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PropertyInfo propertyInfo = null;
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Type operandType = typeof(TOperand);
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propertyInfo = operandType.GetProperty(this.PropertyName);
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if (propertyInfo == null)
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{
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metadata.AddValidationError(SR.MemberNotFound(this.PropertyName, typeof(TOperand).Name));
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}
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else
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{
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Fx.Assert(propertyInfo.GetAccessors().Length > 0, "Property should have at least 1 accessor.");
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this.isOperationFunctionStatic = propertyInfo.GetAccessors()[0].IsStatic;
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isRequired = !this.isOperationFunctionStatic;
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ValidationError validationError;
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if (!MemberExpressionHelper.TryGenerateLinqDelegate(this.PropertyName, false, this.isOperationFunctionStatic, out this.operationFunction, out validationError))
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{
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metadata.AddValidationError(validationError);
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}
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MethodInfo getMethod = propertyInfo.GetGetMethod();
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MethodInfo setMethod = propertyInfo.GetSetMethod();
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if ((getMethod != null && !getMethod.IsStatic) || (setMethod != null && !setMethod.IsStatic))
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{
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isRequired = true;
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}
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}
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}
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MemberExpressionHelper.AddOperandArgument(metadata, this.Operand, isRequired);
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}
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protected override TResult Execute(CodeActivityContext context)
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{
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TOperand operandValue = this.Operand.Get(context);
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if (!this.isOperationFunctionStatic && operandValue == null)
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{
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throw FxTrace.Exception.AsError(new InvalidOperationException(SR.MemberCannotBeNull("Operand", this.GetType().Name, this.DisplayName)));
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}
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TResult result = this.operationFunction(operandValue);
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return result;
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}
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}
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}
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