mcs/class/referencesource/System.Data.Entity/System/Data/Metadata/Edm/NavigationProperty.cs

   1 //---------------------------------------------------------------------
   2 // <copyright file="NavigationProperty.cs" company="Microsoft">
   3 //      Copyright (c) Microsoft Corporation.  All rights reserved.
   4 // </copyright>
   5 //
   6 // @owner       Microsoft
   7 // @backupOwner Microsoft
   8 //---------------------------------------------------------------------
   9 using System.Collections.Generic;
  10 using System.Data.Common;
  11 using System.Diagnostics;
  12 using System.Threading;
  13 using System.Linq;
  14
  15 namespace System.Data.Metadata.Edm
  16 {
  17     /// <summary>
  18     /// Represent the edm navigation property class
  19     /// </summary>
  20     public sealed class NavigationProperty : EdmMember
  21     {
  22         #region Constructors
  23         /// <summary>
  24         /// Initializes a new instance of the navigation property class
  25         /// </summary>
  26         /// <param name="name">name of the navigation property</param>
  27         /// <param name="typeUsage">TypeUsage object containing the navigation property type and its facets</param>
  28         /// <exception cref="System.ArgumentNullException">Thrown if name or typeUsage arguments are null</exception>
  29         /// <exception cref="System.ArgumentException">Thrown if name argument is empty string</exception>
  30         internal NavigationProperty(string name, TypeUsage typeUsage)
  31             : base(name, typeUsage)
  32         {
  33             EntityUtil.CheckStringArgument(name, "name");
  34             EntityUtil.GenericCheckArgumentNull(typeUsage, "typeUsage");
  35             _accessor = new NavigationPropertyAccessor(name);
  36         }
  37
  38         /// <summary>
  39         /// Initializes a new OSpace instance of the property class
  40         /// </summary>
  41         /// <param name="name">name of the property</param>
  42         /// <param name="typeUsage">TypeUsage object containing the property type and its facets</param>
  43         /// <param name="propertyInfo">for the property</param>
  44         internal NavigationProperty(string name, TypeUsage typeUsage, System.Reflection.PropertyInfo propertyInfo)
  45             : this(name, typeUsage)
  46         {
  47             System.Diagnostics.Debug.Assert(name == propertyInfo.Name, "different PropertyName?");
  48             if (null != propertyInfo)
  49             {
  50                 System.Reflection.MethodInfo method;
  51
  52                 method = propertyInfo.GetGetMethod();
  53                 PropertyGetterHandle = ((null != method) ? method.MethodHandle : default(System.RuntimeMethodHandle));
  54             }
  55         }
  56         #endregion
  57
  58         /// <summary>
  59         /// Returns the kind of the type
  60         /// </summary>
  61         public override BuiltInTypeKind BuiltInTypeKind { get { return BuiltInTypeKind.NavigationProperty; } }
  62
  63         #region Fields
  64         internal const string RelationshipTypeNamePropertyName = "RelationshipType";
  65         internal const string ToEndMemberNamePropertyName = "ToEndMember";
  66         private RelationshipType _relationshipType;
  67         private RelationshipEndMember _toEndMember;
  68         private RelationshipEndMember _fromEndMember;
  69
  70         /// <summary>Store the handle, allowing the PropertyInfo/MethodInfo/Type references to be GC'd</summary>
  71         internal readonly System.RuntimeMethodHandle PropertyGetterHandle;
  72
  73         /// <summary>cached dynamic methods to access the property values from a CLR instance</summary>
  74         private readonly NavigationPropertyAccessor _accessor;
  75         #endregion
  76
  77         /// <summary>
  78         /// Gets/Sets the relationship type that this navigation property operates on
  79         /// </summary>
  80         /// <exception cref="System.InvalidOperationException">Thrown if the NavigationProperty instance is in ReadOnly state</exception>
  81         [MetadataProperty(BuiltInTypeKind.RelationshipType, false)]
  82         public RelationshipType RelationshipType
  83         {
  84             get
  85             {
  86                 return _relationshipType;
  87             }
  88             internal set
  89             {
  90                 _relationshipType = value;
  91             }
  92         }
  93
  94         /// <summary>
  95         /// Gets/Sets the to relationship end member in the navigation
  96         /// </summary>
  97         /// <exception cref="System.InvalidOperationException">Thrown if the NavigationProperty instance is in ReadOnly state</exception>
  98         [MetadataProperty(BuiltInTypeKind.RelationshipEndMember, false)]
  99         public RelationshipEndMember ToEndMember
 100         {
 101             get
 102             {
 103                 return _toEndMember;
 104             }
 105             internal set
 106             {
 107                 _toEndMember = value;
 108             }
 109         }
 110
 111         /// <summary>
 112         /// Gets/Sets the from relationship end member in the navigation
 113         /// </summary>
 114         /// <exception cref="System.InvalidOperationException">Thrown if the NavigationProperty instance is in ReadOnly state</exception>
 115         [MetadataProperty(BuiltInTypeKind.RelationshipEndMember, false)]
 116         public RelationshipEndMember FromEndMember
 117         {
 118             get
 119             {
 120                 return _fromEndMember;
 121             }
 122             internal set
 123             {
 124                 _fromEndMember = value;
 125             }
 126         }
 127
 128         internal NavigationPropertyAccessor Accessor
 129         {
 130             get { return _accessor; }
 131         }
 132
 133         /// <summary>
 134         /// Where the given navigation property is on the dependent end of a referential constraint,
 135         /// returns the foreign key properties. Otherwise, returns an empty set. We will return the members in the order
 136         /// of the principal end key properties.
 137         /// </summary>
 138         /// <returns>Foreign key properties</returns>
 139         public IEnumerable<EdmProperty> GetDependentProperties()
 140         {
 141             // Get the declared type
 142             AssociationType associationType = (AssociationType)this.RelationshipType;
 143             Debug.Assert(
 144                          associationType.ReferentialConstraints != null,
 145                          "ReferenceConstraints cannot be null");
 146
 147             if (associationType.ReferentialConstraints.Count > 0)
 148             {
 149                 ReferentialConstraint rc = associationType.ReferentialConstraints[0];
 150                 RelationshipEndMember dependentEndMember = rc.ToRole;
 151
 152                 if (dependentEndMember.EdmEquals(this.FromEndMember))
 153                 {
 154                     //Order the dependant properties in the order of principal end's key members.
 155                     var keyMembers = rc.FromRole.GetEntityType().KeyMembers;
 156                     var dependantProperties = new List<EdmProperty>(keyMembers.Count);
 157                     for (int i = 0; i < keyMembers.Count; i++)
 158                     {
 159                         dependantProperties.Add(rc.ToProperties[rc.FromProperties.IndexOf(((EdmProperty)keyMembers[i]))]);
 160                     }
 161                     return dependantProperties.AsReadOnly();
 162                 }
 163             }
 164
 165             return Enumerable.Empty<EdmProperty>();
 166         }
 167     }
 168 }