WorkflowInstanceExtensionProvider.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / cdf / src / NetFx40 / System.Activities / System / Activities / Hosting / WorkflowInstanceExtensionProvider.cs / 1305376 / WorkflowInstanceExtensionProvider.cs
                        

                        
                            //------------------------------------------------------------------------------ 
// Copyright (c) Microsoft Corporation.  All rights reserved.
//-----------------------------------------------------------------------------

namespace System.Activities.Hosting 
{
    using System.Runtime; 
 
    abstract class WorkflowInstanceExtensionProvider
    { 
        protected WorkflowInstanceExtensionProvider()
        {
        }
 
        public Type Type
        { 
            get; 
            protected set;
        } 

        protected bool GeneratedTypeMatchesDeclaredType
        {
            get; 
            set;
        } 
 
        public abstract object ProvideValue();
 
        public bool IsMatch(object value)
            where TTarget : class
        {
            Fx.Assert(value != null, "extension providers never return a null extension"); 
            if (value is TTarget)
            { 
                if (this.GeneratedTypeMatchesDeclaredType) 
                {
                    return true; 
                }
                else
                {
                    return TypeHelper.AreReferenceTypesCompatible(this.Type, typeof(TTarget)); 
                }
            } 
            else 
            {
                return false; 
            }
        }
    }
 
    class WorkflowInstanceExtensionProvider : WorkflowInstanceExtensionProvider
        where T : class 
    { 
        Func providerFunction;
        bool hasGeneratedValue; 

        public WorkflowInstanceExtensionProvider(Func providerFunction)
            : base()
        { 
            this.providerFunction = providerFunction;
            base.Type = typeof(T); 
        } 

        public override object ProvideValue() 
        {
            T value = this.providerFunction();
            if (!this.hasGeneratedValue)
            { 
                base.GeneratedTypeMatchesDeclaredType = object.ReferenceEquals(value.GetType(), this.Type);
                this.hasGeneratedValue = true; 
            } 

            return value; 
        }
    }
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.

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