AttributeConverter.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / cdf / src / NetFx40 / Tools / System.Activities.Presentation / System / Activities / Presentation / Xaml / AttributeConverter.cs / 1305376 / AttributeConverter.cs
                        
                        
                            //---------------------------------------------------------------- 
// Copyright (c) Microsoft Corporation.  All rights reserved.
//---------------------------------------------------------------

namespace System.Activities.Presentation.Xaml 
{
    using System.Collections.Generic; 
    using System.ComponentModel; 
    using System.ComponentModel.Design.Serialization;
    using System.Globalization; 
    using System.Reflection;
    using System.Collections;
    using System.Runtime;
 
    //AttributeConverter is to convert some XAML-unfriendly attributes (without default ctor) to InstanceDescriptor for XAML serialization
    //AttributeInfo is a helper class to provide type specfic info for each Attribute class 
    abstract class AttributeInfo where TAttribute : Attribute 
    {
        public abstract ConstructorInfo GetConstructor(); 
        public abstract ICollection GetConstructorArguments(TAttribute attribute);
        //whether to use argumented-ctor for serialization even when there's default ctor
        public abstract bool LookupConstructionRequiresArguments { get; }
    } 

    class AttributeConverter : TypeConverter 
        where TAttribute:Attribute 
        where TAttributeInfo:AttributeInfo, new()
    { 
        TAttributeInfo attributeInfo = new TAttributeInfo();
        static ConstructorInfo attributeConstructor = null;

        ConstructorInfo Constructor 
        {
            get 
            { 
                //no need to lock here because every thread will generate the same constructor info even in race condition
                //and cost to get the constructor is relative small 
                if (AttributeConverter.attributeConstructor == null)
                {
                    AttributeConverter.attributeConstructor = this.attributeInfo.GetConstructor();
                } 

                return AttributeConverter.attributeConstructor; 
            } 
        }
 
        public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType)
        {
            if (destinationType == typeof(InstanceDescriptor))
            { 
                return true;
            } 
            return base.CanConvertTo(context, destinationType); 
        }
 
        public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType)
        {
            return false;
        } 

        public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType) 
        { 
            if (destinationType != typeof(InstanceDescriptor))
            { 
                return base.ConvertTo(context, culture, value, destinationType);
            }

            TAttribute attribute = value as TAttribute; 
            if (attribute == null)
            { 
                throw FxTrace.Exception.AsError(new ArgumentException( 
                    string.Format(CultureInfo.CurrentCulture, SR.AttributeConverter_ValueMustBeAttribute, typeof(TAttribute)),
                    "value")); 
            }

            return new InstanceDescriptor(this.Constructor, this.attributeInfo.GetConstructorArguments(attribute), true);
        } 
    }
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
//---------------------------------------------------------------- 
// Copyright (c) Microsoft Corporation.  All rights reserved.
//---------------------------------------------------------------

namespace System.Activities.Presentation.Xaml 
{
    using System.Collections.Generic; 
    using System.ComponentModel; 
    using System.ComponentModel.Design.Serialization;
    using System.Globalization; 
    using System.Reflection;
    using System.Collections;
    using System.Runtime;
 
    //AttributeConverter is to convert some XAML-unfriendly attributes (without default ctor) to InstanceDescriptor for XAML serialization
    //AttributeInfo is a helper class to provide type specfic info for each Attribute class 
    abstract class AttributeInfo where TAttribute : Attribute 
    {
        public abstract ConstructorInfo GetConstructor(); 
        public abstract ICollection GetConstructorArguments(TAttribute attribute);
        //whether to use argumented-ctor for serialization even when there's default ctor
        public abstract bool LookupConstructionRequiresArguments { get; }
    } 

    class AttributeConverter : TypeConverter 
        where TAttribute:Attribute 
        where TAttributeInfo:AttributeInfo, new()
    { 
        TAttributeInfo attributeInfo = new TAttributeInfo();
        static ConstructorInfo attributeConstructor = null;

        ConstructorInfo Constructor 
        {
            get 
            { 
                //no need to lock here because every thread will generate the same constructor info even in race condition
                //and cost to get the constructor is relative small 
                if (AttributeConverter.attributeConstructor == null)
                {
                    AttributeConverter.attributeConstructor = this.attributeInfo.GetConstructor();
                } 

                return AttributeConverter.attributeConstructor; 
            } 
        }
 
        public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType)
        {
            if (destinationType == typeof(InstanceDescriptor))
            { 
                return true;
            } 
            return base.CanConvertTo(context, destinationType); 
        }
 
        public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType)
        {
            return false;
        } 

        public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType) 
        { 
            if (destinationType != typeof(InstanceDescriptor))
            { 
                return base.ConvertTo(context, culture, value, destinationType);
            }

            TAttribute attribute = value as TAttribute; 
            if (attribute == null)
            { 
                throw FxTrace.Exception.AsError(new ArgumentException( 
                    string.Format(CultureInfo.CurrentCulture, SR.AttributeConverter_ValueMustBeAttribute, typeof(TAttribute)),
                    "value")); 
            }

            return new InstanceDescriptor(this.Constructor, this.attributeInfo.GetConstructorArguments(attribute), true);
        } 
    }
} 

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

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