TypeExtension.cs source code in C# .NET

                        Code:
                         / DotNET / DotNET / 8.0 / untmp / WIN_WINDOWS / lh_tools_devdiv_wpf / Windows / wcp / Framework / System / Windows / Markup / TypeExtension.cs / 1 / TypeExtension.cs
                        
                        
                            /****************************************************************************\ 
*
* File: TypeExtension.cs
*
*  Class for Xaml markup extension for a Type reference 
*
* Copyright (C) 2004 by Microsoft Corporation.  All rights reserved. 
* 
\***************************************************************************/
 
using System;
using System.Windows;
using System.ComponentModel;
 
namespace System.Windows.Markup
{ 
    ///  
    ///  Class for Xaml markup extension for a Type reference.
    ///  
    [TypeConverter(typeof(TypeExtensionConverter))]
    [MarkupExtensionReturnType(typeof(Type))]
    public class TypeExtension : MarkupExtension
    { 
        /// 
        ///  Default Constructor 
        ///  
        public TypeExtension()
        { 
        }

        /// 
        ///  Constructor that takes a type name 
        /// 
        public TypeExtension(string typeName) 
        { 
            if (typeName == null)
            { 
                throw new ArgumentNullException("typeName");
            }

            _typeName = typeName; 
        }
 
        ///  
        /// Constructor that takes a type
        ///  
        public TypeExtension(Type type)
        {
            if (type == null)
            { 
                throw new ArgumentNullException("type");
            } 
 
            _type = type;
            // we would like to set TypeName here, but we can't because we can't resolve its namespace 
        }

        /// 
        ///  Return an object that should be set on the targetObject's targetProperty 
        ///  for this markup extension.  TypeExtension resolves a string into a Type
        ///  and returns it. 
        ///  
        /// Object that can provide services for the markup extension.
        ///  
        ///  The object to set on this property.
        /// 
        public override object ProvideValue(IServiceProvider serviceProvider)
        { 
            // If a type was supplied, no context nor type name are needed
 
            if (_type != null) 
            {
                return _type; 
            }

            // Validate the initialization
 
            if (_typeName == null)
            { 
                throw new InvalidOperationException(SR.Get(SRID.MarkupExtensionTypeName)); 
            }
 
            // Get the IXamlTypeResolver from the service provider

            IXamlTypeResolver xamlTypeResolver = serviceProvider.GetService(typeof(IXamlTypeResolver)) as IXamlTypeResolver;
            if( xamlTypeResolver == null ) 
            {
                throw new InvalidOperationException( SR.Get(SRID.MarkupExtensionNoContext, GetType().Name, "IXamlTypeResolver" )); 
            } 

            // Get the type 

            _type = xamlTypeResolver.Resolve(_typeName);

            if (_type == null) 
            {
                throw new InvalidOperationException(SR.Get(SRID.MarkupExtensionTypeNameBad, _typeName)); 
            } 

            return _type; 
            // we could cash the result of type as _type, but it might cause some problems, and in theory we shouldn't need to
        }

        ///  
        ///  The typename represented by this markup extension.  The name has the format
        ///  Prefix:Typename, where Prefix is the xml namespace prefix for this type. 
        ///  
        [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
        public string TypeName 
        {
            get { return _typeName; }
            set
            { 
                if (value == null)
                { 
                    throw new ArgumentNullException("value"); 
                }
 
                _typeName = value;
                _type = null; // so that ProvideValue does not use the existing type
            }
        } 

        ///  
        ///  The type represented by this markup extension. 
        /// 
        [DefaultValue(null)] 
        [ConstructorArgument("type")]
        public Type Type
        {
            get { return _type; } 
            set
            { 
                if (value == null) 
                {
                    throw new ArgumentNullException("value"); 
                }

                _type = value;
                _typeName = null; // so that ProvideValue does not use the existing typeName 
            }
        } 
 
        private string _typeName;
        private Type _type; 
    }
}


// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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TypeExtension.cs source code in C# .NET

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