MemberCollection.cs source code in C# .NET

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Code:

/ 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / DataEntity / System / Data / Metadata / Edm / MemberCollection.cs / 1305376 / MemberCollection.cs

                            //---------------------------------------------------------------------- 
// 
//      Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// 
// @owner       [....]
// @backupOwner [....] 
//--------------------------------------------------------------------- 

using System; 
using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Data.Common; 
using System.Reflection;
using System.Text; 
using System.Diagnostics; 
using System.Globalization;
 
namespace System.Data.Metadata.Edm
{
    /// 
    /// Class representing a collection of member objects 
    /// 
    internal sealed class MemberCollection : MetadataCollection 
    { 
        // This way this collection works is that it has storage for members on the current type and access to
        // members in the base types. As of that requirement, MemberCollection has a reference back to the declaring 
        // type that owns this collection. Whenever MemberCollection is asked to do a look by name, it looks at the
        // current collection, if it doesn't find it, then it ask for it from the declaring type's base type's
        // MemberCollection. Because of this order, members in derived types hide members in the base type if they
        // have the same name. For look up by index, base type members have lower index then current type's members. 
        // Add/Update/Remove operations on this collection is only allowed for members owned by this MemberCollection
        // and not allowed for members owned by MemberCollections in the base types. For example, if the caller tries 
        // to remove a member by ordinal which is within the base type's member ordinal range, it throws an exception. 
        // Hence, base type members are in a sense "readonly" to this MemberCollection. When enumerating all the
        // members, the enumeration starts from members in the root type in the inheritance chain. With this special 
        // enumeration requirement, we have a specialized enumerator class for this MemberCollection. See the
        // Enumerator class for details on how it works.

        #region Constructors 
        /// 
        /// Default constructor for constructing an empty collection 
        ///  
        /// The type that has this member collection
        /// Thrown if the declaring type is null 
        public MemberCollection(StructuralType declaringType)
            : this(declaringType, null)
        {
        } 

        ///  
        /// The constructor for constructing the collection with the given items 
        /// 
        /// The type that has this member collection 
        /// The items to populate the collection
        /// Thrown if the declaring type is null
        public MemberCollection(StructuralType declaringType, IEnumerable items)
            : base(items) 
        {
            Debug.Assert(declaringType != null, "This member collection must belong to a declaring type"); 
            _declaringType = declaringType; 
        }
        #endregion 

        #region Fields
        private StructuralType _declaringType;
        #endregion 

        #region Properties 
        ///  
        /// Returns the collection as a readonly collection
        ///  
        public override System.Collections.ObjectModel.ReadOnlyCollection AsReadOnly
        {
            get
            { 
                return new System.Collections.ObjectModel.ReadOnlyCollection(this);
            } 
        } 

        ///  
        /// Gets the count on the number of items in the collection
        /// 
        public override int Count
        { 
            get
            { 
                return GetBaseTypeMemberCount() + base.Count; 
            }
        } 

        /// 
        /// Gets an item from the collection with the given index
        ///  
        /// The index to search for
        /// An item from the collection 
        /// Thrown if the index is out of the range for the Collection 
        /// Always thrown on setter
        public override EdmMember this[int index] 
        {
            get
            {
                int relativeIndex = GetRelativeIndex(index); 
                if (relativeIndex < 0)
                { 
                    // This means baseTypeMemberCount must be non-zero, so we can safely cast the base type to StructuralType 
                    return ((StructuralType)_declaringType.BaseType).Members[index];
                } 

                return base[relativeIndex];
            }
            set 
            {
                throw EntityUtil.OperationOnReadOnlyCollection(); 
            } 
        }
 
        /// 
        /// Gets an item from the collection with the given identity
        /// 
        /// The identity of the item to search for 
        /// An item from the collection
        /// Thrown if identity argument passed in is null 
        /// Thrown if the Collection does not have an item with the given identity 
        /// Always thrown on setter
        public override EdmMember this[string identity] 
        {
            get
            {
                return GetValue(identity, false); 
            }
            set 
            { 
                throw EntityUtil.OperationOnReadOnlyCollection();
            } 
        }

        /// 
        /// Adds an item to the collection 
        /// 
        /// The item to add to the list 
        /// Thrown if member argument is null 
        /// Thrown if the member passed in or the collection itself instance is in ReadOnly state
        /// Thrown if the member that is being added already belongs to another MemberCollection 
        /// Thrown if the MemberCollection already contains a member with the same identity
        public override void Add(EdmMember member)
        {
            // Make sure the member is valid for the add operation. 
            ValidateMemberForAdd(member, "member");
 
            base.Add(member); 

            // Fix up the declaring type 
            member.ChangeDeclaringTypeWithoutCollectionFixup(_declaringType);
        }

        ///  
        /// Determines if this collection contains an item of the given identity
        ///  
        /// The identity of the item to check for 
        /// True if the collection contains the item with the given identity
        public override bool ContainsIdentity(string identity) 
        {
            if (base.ContainsIdentity(identity))
            {
                return true; 
            }
 
            // The item is not in this collection, check the base type member collection 
            EdmType baseType = _declaringType.BaseType;
            if (baseType != null && ((StructuralType)baseType).Members.Contains(identity)) 
            {
                return true;
            }
 
            return false;
        } 
 
        /// 
        /// Find the index of an item 
        /// 
        /// The item whose index is to be looked for
        /// The index of the found item, -1 if not found
        public override int IndexOf(EdmMember item) 
        {
            // Try to get it from this collection, if found, then the relative index needs to be added with the number 
            // of members in the base type to get the absolute index 
            int relativeIndex = base.IndexOf(item);
            if (relativeIndex != -1) 
            {
                return relativeIndex + GetBaseTypeMemberCount();
            }
 
            // Try to find it in the base type
            StructuralType baseType = _declaringType.BaseType as StructuralType; 
            if (baseType != null) 
            {
                return baseType.Members.IndexOf(item); 
            }

            return -1;
        } 

        ///  
        /// Copies the items in this collection to an array 
        /// 
        /// The array to copy to 
        /// The index in the array at which to start the copy
        /// Thrown if array argument is null
        /// Thrown if the arrayIndex is less than zero
        /// Thrown if the array argument passed in with respect to the arrayIndex passed in not big enough to hold the MemberCollection being copied 
        public override void CopyTo(EdmMember[] array, int arrayIndex)
        { 
            // Check on the array index 
            if (arrayIndex < 0)
            { 
                throw EntityUtil.ArgumentOutOfRange("arrayIndex");
            }

            // Check if the array together with the array index has enough room to copy 
            int baseTypeMemberCount = GetBaseTypeMemberCount();
            if (base.Count + baseTypeMemberCount > array.Length - arrayIndex) 
            { 
                throw EntityUtil.Argument("arrayIndex");
            } 

            // If the base type has any members, copy those first
            if (baseTypeMemberCount > 0)
            { 
                ((StructuralType)_declaringType.BaseType).Members.CopyTo(array, arrayIndex);
            } 
 
            base.CopyTo(array, arrayIndex + baseTypeMemberCount);
        } 

        /// 
        /// Gets an item from the collection with the given identity
        ///  
        /// The identity of the item to search for
        /// Whether case is ignore in the search 
        /// An item from the collection, null if the item is not found 
        /// True an item is retrieved
        /// if identity argument is null 
        public override bool TryGetValue(string identity, bool ignoreCase, out EdmMember item)
        {
            // See if it's in this collection
            if (!base.TryGetValue(identity, ignoreCase, out item)) 
            {
                // Now go to the parent type to find it 
                EdmType baseType = _declaringType.BaseType; 
                if (baseType != null)
                { 
                    ((StructuralType)baseType).Members.TryGetValue(identity, ignoreCase, out item);
                }
            }
 
            return item != null;
        } 
 
        /// 
        /// Gets an itme with identity 
        /// 
        /// 
        /// 
        ///  
        public override EdmMember GetValue(string identity, bool ignoreCase)
        { 
            EdmMember item = null; 

            if (!TryGetValue(identity, ignoreCase, out item)) 
            {
                throw EntityUtil.ItemInvalidIdentity(identity, "identity");
            }
 
            return item;
        } 
 
        /// 
        /// Get the declared only members of a particular type 
        /// 
        internal ReadOnlyMetadataCollection GetDeclaredOnlyMembers() where T : EdmMember
        {
            MetadataCollection newCollection = new MetadataCollection(); 
            for (int i = 0; i < base.Count; i++)
            { 
                T member = base[i] as T; 
                if (member != null)
                { 
                    newCollection.Add(member);
                }
            }
 
            return newCollection.AsReadOnlyMetadataCollection();
        } 
 
        /// 
        /// Get the number of members the base type has.  If the base type is not a structural type or has no 
        /// members, it returns 0
        /// 
        /// The number of members in the base type
        private int GetBaseTypeMemberCount() 
        {
            // The count of members is what in this collection plus base type's member collection 
            StructuralType baseType = _declaringType.BaseType as StructuralType; 
            if (baseType != null)
            { 
                return baseType.Members.Count;
            }

            return 0; 
        }
 
        ///  
        /// Gets the index relative to this collection for the given index.  For an index to really refers to something in
        /// the base type, the return value is negative relative to this collection.  For an index refers to something in this 
        /// collection, the return value is positive.  In both cases, it's simply (index) - (base type member count)
        /// 
        /// The relative index
        private int GetRelativeIndex(int index) 
        {
            int baseTypeMemberCount = GetBaseTypeMemberCount(); 
            int thisTypeMemberCount = base.Count; 

            // Check if the index is in range 
            if (index < 0 || index >= baseTypeMemberCount + thisTypeMemberCount)
            {
                throw EntityUtil.ArgumentOutOfRange("index");
            } 

            return index - baseTypeMemberCount; 
        } 

        private void ValidateMemberForAdd(EdmMember member, string argumentName) 
        {
            // Check to make sure the given member is not associated with another type
            EntityUtil.GenericCheckArgumentNull(member, argumentName);
 
            Debug.Assert(member.DeclaringType == null, string.Format(CultureInfo.CurrentCulture, "The member {0} already has a declaring type, it cannot be added to this collection.", argumentName));
 
            // Validate the item with the declaring type. 
            _declaringType.ValidateMemberForAdd(member);
        } 

        #endregion
    }
} 

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

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