PropertyReference.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / cdf / src / NetFx40 / System.Activities / System / Activities / Expressions / PropertyReference.cs / 1305376 / PropertyReference.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// Copyright (c) Microsoft Corporation.  All rights reserved.
//-----------------------------------------------------------------------------

namespace System.Activities.Expressions 
{
    using System.ComponentModel; 
    using System.Reflection; 
    using System.Runtime;
    using System.Runtime.Serialization; 

    public sealed class PropertyReference : CodeActivity>
    {
        PropertyInfo propertyInfo; 

        [DefaultValue(null)] 
        public string PropertyName 
        {
            get; 
            set;
        }

        public InArgument Operand 
        {
            get; 
            set; 
        }
 
        protected override void CacheMetadata(CodeActivityMetadata metadata)
        {
            bool isRequired = false;
            if (typeof(TOperand).IsEnum) 
            {
                metadata.AddValidationError(SR.TargetTypeCannotBeEnum(this.GetType().Name, this.DisplayName)); 
            } 
            else if (typeof(TOperand).IsValueType)
            { 
                metadata.AddValidationError(SR.TargetTypeIsValueType(this.GetType().Name, this.DisplayName));
            }

            if (string.IsNullOrEmpty(this.PropertyName)) 
            {
                metadata.AddValidationError(SR.ActivityPropertyMustBeSet("PropertyName", this.DisplayName)); 
            } 
            else
            { 
                Type operandType = typeof(TOperand);
                this.propertyInfo = operandType.GetProperty(this.PropertyName);

                if (this.propertyInfo == null) 
                {
                    metadata.AddValidationError(SR.MemberNotFound(PropertyName, typeof(TOperand).Name)); 
                } 
                else
                { 
                    MethodInfo getMethod = this.propertyInfo.GetGetMethod();
                    MethodInfo setMethod = this.propertyInfo.GetSetMethod();

                    // Only allow access to public properties, EXCEPT that Locations are top-level variables 
                    // from the other's perspective, not internal properties, so they're okay as a special case.
                    // E.g. "[N]" from the user's perspective is not accessing a nonpublic property, even though 
                    // at an implementation level it is. 
                    if (setMethod == null && TypeHelper.AreTypesCompatible(this.propertyInfo.DeclaringType, typeof(Location)) == false)
                    { 
                        metadata.AddValidationError(SR.ReadonlyPropertyCannotBeSet(this.propertyInfo.DeclaringType, this.propertyInfo.Name));
                    }

                    if ((getMethod != null && !getMethod.IsStatic) || (setMethod != null && !setMethod.IsStatic)) 
                    {
                        isRequired = true; 
                    } 
                }
            } 
            MemberExpressionHelper.AddOperandArgument(metadata, this.Operand, isRequired);
        }
        protected override Location Execute(CodeActivityContext context)
        { 
            Fx.Assert(this.propertyInfo != null, "propertyInfo must not be null");
            return new PropertyLocation(this.propertyInfo, this.Operand.Get(context)); 
        } 

        [DataContract] 
        class PropertyLocation : Location
        {
            [DataMember(EmitDefaultValue = false)]
            object owner; 

            [DataMember] 
            PropertyInfo propertyInfo; 

            public PropertyLocation(PropertyInfo propertyInfo, object owner) 
                : base()
            {
                this.propertyInfo = propertyInfo;
                this.owner = owner; 
            }
 
            public override T Value 
            {
                get 
                {
                    // Only allow access to public properties, EXCEPT that Locations are top-level variables
                    // from the other's perspective, not internal properties, so they're okay as a special case.
                    // E.g. "[N]" from the user's perspective is not accessing a nonpublic property, even though 
                    // at an implementation level it is.
                    if (this.propertyInfo.GetGetMethod() == null && TypeHelper.AreTypesCompatible(this.propertyInfo.DeclaringType, typeof(Location)) == false) 
                    { 
                        throw FxTrace.Exception.AsError(new InvalidOperationException(SR.WriteonlyPropertyCannotBeRead(this.propertyInfo.DeclaringType, this.propertyInfo.Name)));
                    } 

                    return (T)this.propertyInfo.GetValue(this.owner, null);
                }
                set 
                {
                    this.propertyInfo.SetValue(this.owner, value, null); 
                } 
            }
        } 
    }
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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PropertyReference.cs source code in C# .NET

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