mcs/class/referencesource/System.Data.Linq/DataBindingList.cs

   1 using System.Collections;
   2 using System.Collections.Generic;
   3 using System.ComponentModel;
   4 using System.Linq;
   5 using System.Data.Linq.Mapping;
   6 using System.Reflection;
   7 using System.Runtime.CompilerServices;
   8
   9 namespace System.Data.Linq.Provider {
  10     internal static class BindingList {
  11         [MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.NoOptimization)]
  12         internal static IBindingList Create<T>(DataContext context, IEnumerable<T> sequence) {
  13             List<T> list = sequence.ToList();
  14             MetaTable metaTable = context.Services.Model.GetTable(typeof(T));
  15             if (metaTable != null) {
  16                 ITable table = context.GetTable(metaTable.RowType.Type);
  17                 Type bindingType = typeof(DataBindingList<>).MakeGenericType(metaTable.RowType.Type);
  18                 return (IBindingList)Activator.CreateInstance(bindingType,
  19                     BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic, null,
  20                     new object[] { list, table }, null
  21                     );
  22             } else {
  23                 return new SortableBindingList<T>(list);
  24             }
  25         }
  26     }
  27
  28     internal class DataBindingList<TEntity> : SortableBindingList<TEntity>
  29         where TEntity : class {
  30         private Table<TEntity> data;
  31         private TEntity addNewInstance;
  32         private TEntity cancelNewInstance;
  33         private bool addingNewInstance;
  34
  35         internal DataBindingList(IList<TEntity> sequence, Table<TEntity> data)
  36             : base(sequence != null ? sequence : new List<TEntity>()) {
  37             if (sequence == null) {
  38                 throw Error.ArgumentNull("sequence");
  39             }
  40             if (data == null) {
  41                 throw Error.ArgumentNull("data");
  42             }
  43
  44             this.data = data;
  45         }
  46
  47         protected override object AddNewCore() {
  48             addingNewInstance = true;
  49             addNewInstance = (TEntity)base.AddNewCore();
  50             return addNewInstance;
  51         }
  52
  53         protected override void InsertItem(int index, TEntity item) {
  54             base.InsertItem(index, item);
  55             if (!addingNewInstance && index >= 0 && index <= Count) {
  56                 this.data.InsertOnSubmit(item);
  57             }
  58         }
  59
  60         protected override void RemoveItem(int index) {
  61             if (index >= 0 && index < Count && this[index] == cancelNewInstance) {
  62                 cancelNewInstance = null;
  63             }
  64             else {
  65                 this.data.DeleteOnSubmit(this[index]);
  66             }
  67
  68             base.RemoveItem(index);
  69         }
  70
  71         protected override void SetItem(int index, TEntity item) {
  72             TEntity removedItem = this[index];
  73             base.SetItem(index, item);
  74             if (index >= 0 && index < Count) {
  75                 //Check to see if the user is trying to set an item that is currently being added via AddNew
  76                 //If so then the list should not continue the AddNew; but instead add the item
  77                 //that is being passed in.
  78                 if (removedItem == addNewInstance) {
  79                     addNewInstance = null;
  80                     addingNewInstance = false;
  81                 }
  82                 else {
  83                     this.data.DeleteOnSubmit(removedItem);
  84                 }
  85                 this.data.InsertOnSubmit(item);
  86             }
  87         }
  88
  89         protected override void ClearItems() {
  90             this.data.DeleteAllOnSubmit(this.data.ToList());
  91             base.ClearItems();
  92         }
  93
  94         public override void EndNew(int itemIndex) {
  95             if (itemIndex >= 0 && itemIndex < Count && this[itemIndex] == addNewInstance) {
  96                 this.data.InsertOnSubmit(addNewInstance);
  97                 addNewInstance = null;
  98                 addingNewInstance = false;
  99             }
 100
 101             base.EndNew(itemIndex);
 102         }
 103
 104         public override void CancelNew(int itemIndex) {
 105             if (itemIndex >= 0 && itemIndex < Count && this[itemIndex] == addNewInstance) {
 106                 cancelNewInstance = addNewInstance;
 107                 addNewInstance = null;
 108                 addingNewInstance = false;
 109             }
 110
 111             base.CancelNew(itemIndex);
 112         }
 113     }
 114 }