IBindingList Interface
Definition
Important
Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
Provides the features required to support both complex and simple scenarios when binding to a data source.
public interface class IBindingList : System::Collections::IListpublic interface IBindingList : System.Collections.IListtype IBindingList = interface
interface ICollection
interface IEnumerable
interface IListtype IBindingList = interface
interface IList
interface ICollection
interface IEnumerablePublic Interface IBindingList
Implements IList- Derived
- Implements
Examples
The following example provides a simple implementation of the IBindingList interface. The CustomerList class stores customer information in a list. This example assumes that you have used the Customer class that can be found in the example in the IEditableObject class.
public ref class CustomersList: public CollectionBase, public IBindingList
{
private:
ListChangedEventArgs^ resetEvent;
ListChangedEventHandler^ onListChanged;
virtual event ListChangedEventHandler^ ListChanged;
public:
property bool AllowEdit
{
// Implements IBindingList.
virtual bool get() sealed
{
return true;
}
}
virtual property bool AllowNew
{
bool get()
{
return true;
}
}
property bool AllowRemove
{
virtual bool get()
{
return true;
}
}
property bool SupportsChangeNotification
{
virtual bool get()
{
return true;
}
}
property bool SupportsSearching
{
virtual bool get()
{
return true;
}
}
property bool SupportsSorting
{
virtual bool get()
{
return true;
}
}
// Methods.
virtual Object^ AddNew()
{
Customer^ c = gcnew Customer( this->Count->ToString() );
List->Add( c );
return c;
}
property bool IsSorted
{
// Unsupported properties.
virtual bool get()
{
throw gcnew NotSupportedException;
return false;
}
}
property ListSortDirection SortDirection
{
virtual ListSortDirection get()
{
throw gcnew NotSupportedException;
return ListSortDirection::Ascending;
}
}
property PropertyDescriptor^ SortProperty
{
virtual PropertyDescriptor^ get()
{
throw gcnew NotSupportedException;
return nullptr;
}
}
// Unsupported Methods.
virtual void AddIndex( PropertyDescriptor^ property )
{
throw gcnew NotSupportedException;
}
virtual void ApplySort( PropertyDescriptor^ property, ListSortDirection direction )
{
throw gcnew NotSupportedException;
}
virtual int Find( PropertyDescriptor^ property, Object^ key )
{
throw gcnew NotSupportedException;
return 0;
}
virtual void RemoveIndex( PropertyDescriptor^ property )
{
throw gcnew NotSupportedException;
}
virtual void RemoveSort()
{
throw gcnew NotSupportedException;
}
// Worker functions to populate the list with data.
static Customer^ ReadCustomer1()
{
Customer^ cust = gcnew Customer( "536-45-1245" );
cust->FirstName = "Jo";
cust->LastName = "Brown";
return cust;
}
static Customer^ ReadCustomer2()
{
Customer^ cust = gcnew Customer( "246-12-5645" );
cust->FirstName = "Robert";
cust->LastName = "Brown";
return cust;
}
protected:
virtual void OnListChanged( ListChangedEventArgs^ ev )
{
if ( onListChanged != nullptr )
{
onListChanged( this, ev );
}
}
virtual void OnClear() override
{
List->Clear();
}
virtual void OnClearComplete() override
{
OnListChanged( resetEvent );
}
virtual void OnInsertComplete( int index, Object^ value ) override
{
Customer^ c = safe_cast<Customer^>(value);
c->Parent = this;
OnListChanged( gcnew ListChangedEventArgs( ListChangedType::ItemAdded,index ) );
}
virtual void OnRemoveComplete( int index, Object^ value ) override
{
Customer^ c = safe_cast<Customer^>(value);
c->Parent = this;
OnListChanged( gcnew ListChangedEventArgs( ListChangedType::ItemDeleted,index ) );
}
virtual void OnSetComplete( int index, Object^ oldValue, Object^ newValue ) override
{
if ( oldValue != newValue )
{
Customer^ oldcust = safe_cast<Customer^>(oldValue);
Customer^ newcust = safe_cast<Customer^>(newValue);
oldcust->Parent = 0;
newcust->Parent = this;
OnListChanged( gcnew ListChangedEventArgs( ListChangedType::ItemAdded,index ) );
}
}
public:
// Constructor
CustomersList()
{
resetEvent = gcnew ListChangedEventArgs( ListChangedType::Reset,-1 );
}
void LoadCustomers()
{
IList^ l = static_cast<IList^>(this);
l->Add( ReadCustomer1() );
l->Add( ReadCustomer2() );
OnListChanged( resetEvent );
}
property Object^ Item [int]
{
Object^ get( int index )
{
return static_cast<Customer^>(List->Item[ index ]);
}
void set( int index, Object^ value )
{
List->Item[ index ] = value;
}
}
int Add( Customer^ value )
{
return List->Add( value );
}
Customer^ AddNew()
{
return safe_cast<Customer^>(static_cast<IBindingList^>(this)->AddNew());
}
void Remove( Customer^ value )
{
List->Remove( value );
}
internal:
// Called by Customer when it changes.
void CustomerChanged( Customer^ cust )
{
int index = List->IndexOf( cust );
OnListChanged( gcnew ListChangedEventArgs( ListChangedType::ItemChanged,index ) );
}
};
public class CustomersList : CollectionBase, IBindingList
{
private ListChangedEventArgs resetEvent = new ListChangedEventArgs(ListChangedType.Reset, -1);
private ListChangedEventHandler onListChanged;
public void LoadCustomers()
{
IList l = (IList)this;
l.Add(ReadCustomer1());
l.Add(ReadCustomer2());
OnListChanged(resetEvent);
}
public Customer this[int index]
{
get
{
return (Customer)(List[index]);
}
set
{
List[index] = value;
}
}
public int Add (Customer value)
{
return List.Add(value);
}
public Customer AddNew()
{
return (Customer)((IBindingList)this).AddNew();
}
public void Remove (Customer value)
{
List.Remove(value);
}
protected virtual void OnListChanged(ListChangedEventArgs ev)
{
if (onListChanged != null)
{
onListChanged(this, ev);
}
}
protected override void OnClear()
{
foreach (Customer c in List)
{
c.Parent = null;
}
}
protected override void OnClearComplete()
{
OnListChanged(resetEvent);
}
protected override void OnInsertComplete(int index, object value)
{
Customer c = (Customer)value;
c.Parent = this;
OnListChanged(new ListChangedEventArgs(ListChangedType.ItemAdded, index));
}
protected override void OnRemoveComplete(int index, object value)
{
Customer c = (Customer)value;
c.Parent = this;
OnListChanged(new ListChangedEventArgs(ListChangedType.ItemDeleted, index));
}
protected override void OnSetComplete(int index, object oldValue, object newValue)
{
if (oldValue != newValue)
{
Customer oldcust = (Customer)oldValue;
Customer newcust = (Customer)newValue;
oldcust.Parent = null;
newcust.Parent = this;
OnListChanged(new ListChangedEventArgs(ListChangedType.ItemAdded, index));
}
}
// Called by Customer when it changes.
internal void CustomerChanged(Customer cust)
{
int index = List.IndexOf(cust);
OnListChanged(new ListChangedEventArgs(ListChangedType.ItemChanged, index));
}
// Implements IBindingList.
bool IBindingList.AllowEdit
{
get { return true ; }
}
bool IBindingList.AllowNew
{
get { return true ; }
}
bool IBindingList.AllowRemove
{
get { return true ; }
}
bool IBindingList.SupportsChangeNotification
{
get { return true ; }
}
bool IBindingList.SupportsSearching
{
get { return false ; }
}
bool IBindingList.SupportsSorting
{
get { return false ; }
}
// Events.
public event ListChangedEventHandler ListChanged
{
add
{
onListChanged += value;
}
remove
{
onListChanged -= value;
}
}
// Methods.
object IBindingList.AddNew()
{
Customer c = new Customer(this.Count.ToString());
List.Add(c);
return c;
}
// Unsupported properties.
bool IBindingList.IsSorted
{
get { throw new NotSupportedException(); }
}
ListSortDirection IBindingList.SortDirection
{
get { throw new NotSupportedException(); }
}
PropertyDescriptor IBindingList.SortProperty
{
get { throw new NotSupportedException(); }
}
// Unsupported Methods.
void IBindingList.AddIndex(PropertyDescriptor property)
{
throw new NotSupportedException();
}
void IBindingList.ApplySort(PropertyDescriptor property, ListSortDirection direction)
{
throw new NotSupportedException();
}
int IBindingList.Find(PropertyDescriptor property, object key)
{
throw new NotSupportedException();
}
void IBindingList.RemoveIndex(PropertyDescriptor property)
{
throw new NotSupportedException();
}
void IBindingList.RemoveSort()
{
throw new NotSupportedException();
}
// Worker functions to populate the list with data.
private static Customer ReadCustomer1()
{
Customer cust = new Customer("536-45-1245");
cust.FirstName = "Jo";
cust.LastName = "Brown";
return cust;
}
private static Customer ReadCustomer2()
{
Customer cust = new Customer("246-12-5645");
cust.FirstName = "Robert";
cust.LastName = "Brown";
return cust;
}
}
Public Class CustomersList
Inherits CollectionBase
Implements IBindingList
Private resetEvent As New ListChangedEventArgs(ListChangedType.Reset, -1)
Private onListChanged1 As ListChangedEventHandler
Public Sub LoadCustomers()
Dim l As IList = CType(Me, IList)
l.Add(ReadCustomer1())
l.Add(ReadCustomer2())
OnListChanged(resetEvent)
End Sub
Default Public Property Item(ByVal index As Integer) As Customer
Get
Return CType(List(index), Customer)
End Get
Set(ByVal Value As Customer)
List(index) = Value
End Set
End Property
Public Function Add(ByVal value As Customer) As Integer
Return List.Add(value)
End Function
Public Function AddNew2() As Customer
Return CType(CType(Me, IBindingList).AddNew(), Customer)
End Function
Public Sub Remove(ByVal value As Customer)
List.Remove(value)
End Sub
Protected Overridable Sub OnListChanged(ByVal ev As ListChangedEventArgs)
If (onListChanged1 IsNot Nothing) Then
onListChanged1(Me, ev)
End If
End Sub
Protected Overrides Sub OnClear()
Dim c As Customer
For Each c In List
c.parent = Nothing
Next c
End Sub
Protected Overrides Sub OnClearComplete()
OnListChanged(resetEvent)
End Sub
Protected Overrides Sub OnInsertComplete(ByVal index As Integer, ByVal value As Object)
Dim c As Customer = CType(value, Customer)
c.parent = Me
OnListChanged(New ListChangedEventArgs(ListChangedType.ItemAdded, index))
End Sub
Protected Overrides Sub OnRemoveComplete(ByVal index As Integer, ByVal value As Object)
Dim c As Customer = CType(value, Customer)
c.parent = Me
OnListChanged(New ListChangedEventArgs(ListChangedType.ItemDeleted, index))
End Sub
Protected Overrides Sub OnSetComplete(ByVal index As Integer, ByVal oldValue As Object, ByVal newValue As Object)
If oldValue <> newValue Then
Dim oldcust As Customer = CType(oldValue, Customer)
Dim newcust As Customer = CType(newValue, Customer)
oldcust.parent = Nothing
newcust.parent = Me
OnListChanged(New ListChangedEventArgs(ListChangedType.ItemAdded, index))
End If
End Sub
' Called by Customer when it changes.
Friend Sub CustomerChanged(ByVal cust As Customer)
Dim index As Integer = List.IndexOf(cust)
OnListChanged(New ListChangedEventArgs(ListChangedType.ItemChanged, index))
End Sub
' Implements IBindingList.
ReadOnly Property AllowEdit() As Boolean Implements IBindingList.AllowEdit
Get
Return True
End Get
End Property
ReadOnly Property AllowNew() As Boolean Implements IBindingList.AllowNew
Get
Return True
End Get
End Property
ReadOnly Property AllowRemove() As Boolean Implements IBindingList.AllowRemove
Get
Return True
End Get
End Property
ReadOnly Property SupportsChangeNotification() As Boolean Implements IBindingList.SupportsChangeNotification
Get
Return True
End Get
End Property
ReadOnly Property SupportsSearching() As Boolean Implements IBindingList.SupportsSearching
Get
Return False
End Get
End Property
ReadOnly Property SupportsSorting() As Boolean Implements IBindingList.SupportsSorting
Get
Return False
End Get
End Property
' Events.
Public Event ListChanged As ListChangedEventHandler Implements IBindingList.ListChanged
' Methods.
Function AddNew() As Object Implements IBindingList.AddNew
Dim c As New Customer(Me.Count.ToString())
List.Add(c)
Return c
End Function
' Unsupported properties.
ReadOnly Property IsSorted() As Boolean Implements IBindingList.IsSorted
Get
Throw New NotSupportedException()
End Get
End Property
ReadOnly Property SortDirection() As ListSortDirection Implements IBindingList.SortDirection
Get
Throw New NotSupportedException()
End Get
End Property
ReadOnly Property SortProperty() As PropertyDescriptor Implements IBindingList.SortProperty
Get
Throw New NotSupportedException()
End Get
End Property
' Unsupported Methods.
Sub AddIndex(ByVal prop As PropertyDescriptor) Implements IBindingList.AddIndex
Throw New NotSupportedException()
End Sub
Sub ApplySort(ByVal prop As PropertyDescriptor, ByVal direction As ListSortDirection) Implements IBindingList.ApplySort
Throw New NotSupportedException()
End Sub
Function Find(ByVal prop As PropertyDescriptor, ByVal key As Object) As Integer Implements IBindingList.Find
Throw New NotSupportedException()
End Function
Sub RemoveIndex(ByVal prop As PropertyDescriptor) Implements IBindingList.RemoveIndex
Throw New NotSupportedException()
End Sub
Sub RemoveSort() Implements IBindingList.RemoveSort
Throw New NotSupportedException()
End Sub
' Worker functions to populate the list with data.
Private Shared Function ReadCustomer1() As Customer
Dim cust As New Customer("536-45-1245")
cust.FirstName = "Jo"
cust.LastName = "Brown"
Return cust
End Function
Private Shared Function ReadCustomer2() As Customer
Dim cust As New Customer("246-12-5645")
cust.FirstName = "Robert"
cust.LastName = "Brown"
Return cust
End Function
End Class
Remarks
This interface is implemented by the DataView class. Implementation of a method should exhibit the same behavior as the implementation of that method in the DataView class.
When you call the ApplySort or RemoveSort methods, you should raise a ListChanged event with the Reset enumeration.
When you call the AddNew method, you should raise a ListChanged event with the ItemAdded enumeration carrying the appropriate index. The added row is in a state where pressing the ESC on a DataGridView control can remove the new row. Raising the ListChanged event with the ItemAdded enumeration a second time on this row indicates that the item is now a row not in the "new" state.
When you remove an item or call the CancelEdit method on a new row (if that row implements IEditableObject), you should raise a ListChanged event with the ItemDeleted enumeration carrying the appropriate index.
Properties
| AllowEdit |
Gets whether you can update items in the list. |
| AllowNew |
Gets whether you can add items to the list using AddNew(). |
| AllowRemove |
Gets whether you can remove items from the list, using Remove(Object) or RemoveAt(Int32). |
| Count |
Gets the number of elements contained in the ICollection. (Inherited from ICollection) |
| IsFixedSize |
Gets a value indicating whether the IList has a fixed size. (Inherited from IList) |
| IsReadOnly |
Gets a value indicating whether the IList is read-only. (Inherited from IList) |
| IsSorted |
Gets whether the items in the list are sorted. |
| IsSynchronized |
Gets a value indicating whether access to the ICollection is synchronized (thread safe). (Inherited from ICollection) |
| Item[Int32] |
Gets or sets the element at the specified index. (Inherited from IList) |
| SortDirection |
Gets the direction of the sort. |
| SortProperty |
Gets the PropertyDescriptor that is being used for sorting. |
| SupportsChangeNotification |
Gets whether a ListChanged event is raised when the list changes or an item in the list changes. |
| SupportsSearching |
Gets whether the list supports searching using the Find(PropertyDescriptor, Object) method. |
| SupportsSorting |
Gets whether the list supports sorting. |
| SyncRoot |
Gets an object that can be used to synchronize access to the ICollection. (Inherited from ICollection) |
Methods
| Add(Object) |
Adds an item to the IList. (Inherited from IList) |
| AddIndex(PropertyDescriptor) |
Adds the PropertyDescriptor to the indexes used for searching. |
| AddNew() |
Adds a new item to the list. |
| ApplySort(PropertyDescriptor, ListSortDirection) |
Sorts the list based on a PropertyDescriptor and a ListSortDirection. |
| Clear() |
Removes all items from the IList. (Inherited from IList) |
| Contains(Object) |
Determines whether the IList contains a specific value. (Inherited from IList) |
| CopyTo(Array, Int32) |
Copies the elements of the ICollection to an Array, starting at a particular Array index. (Inherited from ICollection) |
| Find(PropertyDescriptor, Object) |
Returns the index of the row that has the given PropertyDescriptor. |
| GetEnumerator() |
Returns an enumerator that iterates through a collection. (Inherited from IEnumerable) |
| IndexOf(Object) |
Determines the index of a specific item in the IList. (Inherited from IList) |
| Insert(Int32, Object) |
Inserts an item to the IList at the specified index. (Inherited from IList) |
| Remove(Object) |
Removes the first occurrence of a specific object from the IList. (Inherited from IList) |
| RemoveAt(Int32) |
Removes the IList item at the specified index. (Inherited from IList) |
| RemoveIndex(PropertyDescriptor) |
Removes the PropertyDescriptor from the indexes used for searching. |
| RemoveSort() |
Removes any sort applied using ApplySort(PropertyDescriptor, ListSortDirection). |
Events
| ListChanged |
Occurs when the list changes or an item in the list changes. |
Extension Methods
| Cast<TResult>(IEnumerable) |
Casts the elements of an IEnumerable to the specified type. |
| OfType<TResult>(IEnumerable) |
Filters the elements of an IEnumerable based on a specified type. |
| AsParallel(IEnumerable) |
Enables parallelization of a query. |
| AsQueryable(IEnumerable) |
Converts an IEnumerable to an IQueryable. |
