IEditableCollectionView.CanAddNew Property

Definition

Namespace:

System.ComponentModel

Assembly:

WindowsBase.dll

Gets a value that indicates whether a new item can be added to the collection.

public:
 property bool CanAddNew { bool get(); };

public bool CanAddNew { get; }

member this.CanAddNew : bool

Public ReadOnly Property CanAddNew As Boolean

Property Value

Boolean

true if a new item can be added to the collection; otherwise, false.

Examples

The following example checks whether an item can be added to the collection. If CanAddNew is false, the example tells the user that an item cannot be added. Otherwise, it shows a form that prompts the user to add a new item. For the entire sample, see Changing a Collection by Using IEditableCollectionView Sample .

IEditableCollectionView editableCollectionView = 
    itemsControl.Items as IEditableCollectionView; 

if (!editableCollectionView.CanAddNew)
{
    MessageBox.Show("You cannot add items to the list.");
    return;
}

// Create a window that prompts the user to enter a new
// item to sell.
ChangeItemWindow win = new ChangeItemWindow();

//Create a new item to be added to the collection.
win.DataContext = editableCollectionView.AddNew();

// If the user submits the new item, commit the new
// object to the collection.  If the user cancels 
// adding the new item, discard the new item.
if ((bool)win.ShowDialog())
{
    editableCollectionView.CommitNew();
}
else
{
    editableCollectionView.CancelNew();
}

Dim editableCollectionView As IEditableCollectionView = TryCast(itemsControl.Items, IEditableCollectionView)

If Not editableCollectionView.CanAddNew Then
    MessageBox.Show("You cannot add items to the list.")
    Return
End If

' Create a window that prompts the user to enter a new
' item to sell.
Dim win As New ChangeItemWindow()

'Create a new item to be added to the collection.
win.DataContext = editableCollectionView.AddNew()

' If the user submits the new item, commit the new
' object to the collection.  If the user cancels 
' adding the new item, discard the new item.
If CBool(win.ShowDialog()) Then
    editableCollectionView.CommitNew()
Else
    editableCollectionView.CancelNew()
End If

Remarks

An IEditableCollectionView can add a new item if the following are true:

• An item can be added to the underlying collection. For example, if the collection is read-only, CanAddNew is false.

• The IEditableCollectionView can create an object of the type that is in the collection. For example, if the collection is of type ObservableCollection<T>, the IEditableCollectionView must be able to create an object of type T.