NavigationProperty.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / DataEntity / System / Data / Metadata / Edm / NavigationProperty.cs / 1305376 / NavigationProperty.cs
                        
                        
                            //---------------------------------------------------------------------- 
// 
//      Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// 
// @owner       [....]
// @backupOwner [....] 
//--------------------------------------------------------------------- 
using System.Collections.Generic;
using System.Data.Common; 
using System.Diagnostics;
using System.Threading;
using System.Linq;
 
namespace System.Data.Metadata.Edm
{ 
    ///  
    /// Represent the edm navigation property class
    ///  
    public sealed class NavigationProperty : EdmMember
    {
        #region Constructors
        ///  
        /// Initializes a new instance of the navigation property class
        ///  
        /// name of the navigation property 
        /// TypeUsage object containing the navigation property type and its facets
        /// Thrown if name or typeUsage arguments are null 
        /// Thrown if name argument is empty string
        internal NavigationProperty(string name, TypeUsage typeUsage)
            : base(name, typeUsage)
        { 
            EntityUtil.CheckStringArgument(name, "name");
            EntityUtil.GenericCheckArgumentNull(typeUsage, "typeUsage"); 
            _accessor = new NavigationPropertyAccessor(name); 
        }
 
        /// 
        /// Initializes a new OSpace instance of the property class
        /// 
        /// name of the property 
        /// TypeUsage object containing the property type and its facets
        /// for the property 
        internal NavigationProperty(string name, TypeUsage typeUsage, System.Reflection.PropertyInfo propertyInfo) 
            : this(name, typeUsage)
        { 
            System.Diagnostics.Debug.Assert(name == propertyInfo.Name, "different PropertyName?");
            if (null != propertyInfo)
            {
                System.Reflection.MethodInfo method; 

                method = propertyInfo.GetGetMethod(); 
                PropertyGetterHandle = ((null != method) ? method.MethodHandle : default(System.RuntimeMethodHandle)); 
            }
        } 
        #endregion

        /// 
        /// Returns the kind of the type 
        /// 
        public override BuiltInTypeKind BuiltInTypeKind { get { return BuiltInTypeKind.NavigationProperty; } } 
 
        #region Fields
        internal const string RelationshipTypeNamePropertyName = "RelationshipType"; 
        internal const string ToEndMemberNamePropertyName = "ToEndMember";
        private RelationshipType _relationshipType;
        private RelationshipEndMember _toEndMember;
        private RelationshipEndMember _fromEndMember; 

        /// Store the handle, allowing the PropertyInfo/MethodInfo/Type references to be GC'd 
        internal readonly System.RuntimeMethodHandle PropertyGetterHandle; 

        /// cached dynamic methods to access the property values from a CLR instance 
        private readonly NavigationPropertyAccessor _accessor;
        #endregion

        ///  
        /// Gets/Sets the relationship type that this navigation property operates on
        ///  
        /// Thrown if the NavigationProperty instance is in ReadOnly state 
        [MetadataProperty(BuiltInTypeKind.RelationshipType, false)]
        public RelationshipType RelationshipType 
        {
            get
            {
                return _relationshipType; 
            }
            internal set 
            { 
                _relationshipType = value;
            } 
        }

        /// 
        /// Gets/Sets the to relationship end member in the navigation 
        /// 
        /// Thrown if the NavigationProperty instance is in ReadOnly state 
        [MetadataProperty(BuiltInTypeKind.RelationshipEndMember, false)] 
        public RelationshipEndMember ToEndMember
        { 
            get
            {
                return _toEndMember;
            } 
            internal set
            { 
                _toEndMember = value; 
            }
        } 

        /// 
        /// Gets/Sets the from relationship end member in the navigation
        ///  
        /// Thrown if the NavigationProperty instance is in ReadOnly state
        [MetadataProperty(BuiltInTypeKind.RelationshipEndMember, false)] 
        public RelationshipEndMember FromEndMember 
        {
            get 
            {
                return _fromEndMember;
            }
            internal set 
            {
                _fromEndMember = value; 
            } 
        }
 
        internal NavigationPropertyAccessor Accessor
        {
            get { return _accessor; }
        } 

        ///  
        /// Where the given navigation property is on the dependent end of a referential constraint, 
        /// returns the foreign key properties. Otherwise, returns an empty set. We will return the members in the order
        /// of the principal end key properties. 
        /// 
        /// Foreign key properties
        public IEnumerable GetDependentProperties()
        { 
            // Get the declared type
            AssociationType associationType = (AssociationType)this.RelationshipType; 
            Debug.Assert( 
                         associationType.ReferentialConstraints != null,
                         "ReferenceConstraints cannot be null"); 

            if (associationType.ReferentialConstraints.Count > 0)
            {
                ReferentialConstraint rc = associationType.ReferentialConstraints[0]; 
                RelationshipEndMember dependentEndMember = rc.ToRole;
 
                if (dependentEndMember.EdmEquals(this.FromEndMember)) 
                {
                    //Order the dependant properties in the order of principal end's key members. 
                    var keyMembers = rc.FromRole.GetEntityType().KeyMembers;
                    var dependantProperties = new List(keyMembers.Count);
                    for (int i = 0; i < keyMembers.Count; i++)
                    { 
                        dependantProperties.Add(rc.ToProperties[rc.FromProperties.IndexOf(((EdmProperty)keyMembers[i]))]);
                    } 
                    return dependantProperties.AsReadOnly(); 
                }
            } 

            return Enumerable.Empty();
        }
    } 
}

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

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