NavigationPropertySingletonExpression.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 / fx / src / DataWeb / Client / System / Data / Services / Client / ALinq / NavigationPropertySingletonExpression.cs / 1305376 / NavigationPropertySingletonExpression.cs
                        

                        
                            //---------------------------------------------------------------------- 
// 
//      Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//  
//      Respresents a navigation to a singleton property.
//  
// 
// @owner  [....]
//--------------------------------------------------------------------- 
namespace System.Data.Services.Client
{
    #region Private fields.
 
    using System;
    using System.Collections.Generic; 
    using System.Diagnostics; 
    using System.Linq;
    using System.Linq.Expressions; 

    #endregion Private fields.

    /// Expression for a navigation property into a single entity (eg: Customer.BestFriend). 
    internal class NavigationPropertySingletonExpression : ResourceExpression
    { 
        #region Private fields. 

        /// property member name 
        private readonly Expression memberExpression;

        ///  resource type
        private readonly Type resourceType; 

        #endregion Private fields. 
 
        /// 
        /// Creates a NavigationPropertySingletonExpression expression 
        /// 
        /// the return type of the expression
        /// the source expression
        /// property member name 
        /// resource type for expression
        /// expand paths for resource set 
        /// count option for the resource set 
        /// custom query options for resourcse set
        /// projection expression 
        internal NavigationPropertySingletonExpression(Type type, Expression source, Expression memberExpression, Type resourceType, List expandPaths, CountOption countOption, Dictionary customQueryOptions, ProjectionQueryOptionExpression projection)
            : base(source, (ExpressionType)ResourceExpressionType.ResourceNavigationPropertySingleton, type, expandPaths, countOption, customQueryOptions, projection)
        {
            Debug.Assert(memberExpression != null, "memberExpression != null"); 
            Debug.Assert(resourceType != null, "resourceType != null");
 
            this.memberExpression = memberExpression; 
            this.resourceType = resourceType;
        } 

        /// 
        /// Gets the member expression.
        ///  
        internal MemberExpression MemberExpression
        { 
            get 
            {
                return (MemberExpression)this.memberExpression; 
            }
        }

        ///  
        /// The resource type of the singe instance produced by this singleton navigation.
        ///  
        internal override Type ResourceType 
        {
            get { return this.resourceType; } 
        }

        /// 
        /// Singleton navigation properties always produce at most 1 result 
        /// 
        internal override bool IsSingleton 
        { 
            get { return true; }
        } 

        /// 
        /// Does Singleton navigation have query options.
        ///  
        internal override bool HasQueryOptions
        { 
            get 
            {
                return this.ExpandPaths.Count > 0 || 
                    this.CountOption == CountOption.InlineAll ||
                    this.CustomQueryOptions.Count > 0  ||
                    this.Projection != null;
            } 
        }
 
        ///  
        /// Cast changes the type of the ResourceExpression
        ///  
        /// new type
        /// new NavigationPropertySingletonExpression
        internal override ResourceExpression CreateCloneWithNewType(Type type)
        { 
            return new NavigationPropertySingletonExpression(
                type, 
                this.source, 
                this.MemberExpression,
                TypeSystem.GetElementType(type), 
                this.ExpandPaths.ToList(),
                this.CountOption,
                this.CustomQueryOptions.ToDictionary(kvp => kvp.Key, kvp => kvp.Value),
                this.Projection); 
        }
    } 
} 

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

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