RelationshipNavigation.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / DataEntity / System / Data / Objects / DataClasses / RelationshipNavigation.cs / 1305376 / RelationshipNavigation.cs
                        
                        
                            //---------------------------------------------------------------------- 
// 
//      Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// 
// @owner       [....]
// @backupOwner [....] 
//--------------------------------------------------------------------- 

using System; 
using System.Collections.Generic;
using System.Data.Common;
using System.Globalization;
using System.Text; 
using System.Data.Metadata.Edm;
 
namespace System.Data.Objects.DataClasses 
{
    ///  
    /// This class describes a relationship navigation from the
    /// navigation property on one entity to another entity.  It is
    /// used throughout the collections and refs system to describe a
    /// relationship and to connect from the navigation property on 
    /// one end of a relationship to the navigation property on the
    /// other end. 
    ///  
    [Serializable]
    internal class RelationshipNavigation 
    {
        // ------------
        // Constructors
        // ------------ 

        ///  
        /// Creates a navigation object with the given relationship 
        /// name, role name for the source and role name for the
        /// destination. 
        /// 
        /// Canonical-space name of the relationship.
        /// Name of the role which is the source of the navigation.
        /// Name of the role which is the destination of the navigation. 
        /// The navigation property which is the source of the navigation.
        /// The navigation property which is the destination of the navigation. 
        internal RelationshipNavigation(string relationshipName, string from, string to, NavigationPropertyAccessor fromAccessor, NavigationPropertyAccessor toAccessor) 
        {
            EntityUtil.CheckStringArgument(relationshipName, "relationshipName"); 
            EntityUtil.CheckStringArgument(from, "from");
            EntityUtil.CheckStringArgument(to, "to");

            _relationshipName = relationshipName; 
            _from = from;
            _to = to; 
 
            _fromAccessor = fromAccessor;
            _toAccessor = toAccessor; 
        }

        // ------
        // Fields 
        // ------
 
        // The following fields are serialized.  Adding or removing a serialized field is considered 
        // a breaking change.  This includes changing the field type or field name of existing
        // serialized fields. If you need to make this kind of change, it may be possible, but it 
        // will require some custom serialization/deserialization code.
        private readonly string _relationshipName;
        private readonly string _from;
        private readonly string _to; 

        [NonSerialized] 
        private RelationshipNavigation _reverse; 

        [NonSerialized] 
        private NavigationPropertyAccessor _fromAccessor;

        [NonSerialized]
        private NavigationPropertyAccessor _toAccessor; 

        // ---------- 
        // Properties 
        // ----------
 
        /// 
        /// Canonical-space relationship name.
        /// 
        internal string RelationshipName 
        {
            get 
            { 
                return _relationshipName;
            } 
        }

        /// 
        /// Role name for the source of this navigation. 
        /// 
        internal string From 
        { 
            get
            { 
                return _from;
            }
        }
 
        /// 
        /// Role name for the destination of this navigation. 
        ///  
        internal string To
        { 
            get
            {
                return _to;
            } 
        }
 
        ///  
        /// Navigation property name for the destination of this navigation.
        /// NOTE: There is not a FromPropertyAccessor property on RelationshipNavigation because it is not currently accessed anywhere 
        ///       It is only used to calculate the "reverse" RelationshipNavigation.
        /// 
        internal NavigationPropertyAccessor ToPropertyAccessor
        { 
            get { return _toAccessor; }
        } 
 
        internal bool IsInitialized
        { 
            get { return _toAccessor != null && _fromAccessor != null; }
        }

        internal void InitializeAccessors(NavigationPropertyAccessor fromAccessor, NavigationPropertyAccessor toAccessor) 
        {
            _fromAccessor = fromAccessor; 
            _toAccessor = toAccessor; 
        }
 
        /// 
        /// The "reverse" version of this navigation.
        /// 
        internal RelationshipNavigation Reverse 
        {
            get 
            { 
                if (_reverse == null || !_reverse.IsInitialized)
                { 
                    // the reverse relationship is exactly like this
                    // one but from & to are switched
                    _reverse = new RelationshipNavigation(_relationshipName, _to, _from, _toAccessor, _fromAccessor);
                } 

                return _reverse; 
            } 
        }
 
        /// 
        /// Compares this instance to a given Navigation by their values.
        /// 
        public override bool Equals(object obj) 
        {
                RelationshipNavigation compareTo = obj as RelationshipNavigation; 
                return ((this == compareTo) 
                        || ((null != this) && (null != compareTo)
                            && (this.RelationshipName == compareTo.RelationshipName) 
                            && (this.From == compareTo.From)
                            && (this.To == compareTo.To)));
        }
 
        /// 
        /// Returns a value-based hash code. 
        ///  
        /// the hash value of this Navigation
        public override int GetHashCode() 
        {
                return this.RelationshipName.GetHashCode();
        }
 
        // -------
        // Methods 
        // ------- 

        ///  
        /// ToString is provided to simplify debugging, etc.
        /// 
        public override string ToString()
        { 
            return String.Format(CultureInfo.InvariantCulture,
                                 "RelationshipNavigation: ({0},{1},{2})", 
                                 _relationshipName, 
                                 _from,
                                 _to); 
        }
    }
}

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

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