通过

IEditableCollectionView.CanAddNew 属性

  • 参考

定义

命名空间:
System.ComponentModel
程序集:
WindowsBase.dll

获取一个值，该值指示是否可以将新项添加到集合中。

public:
 property bool CanAddNew { bool get(); };
public bool CanAddNew { get; }
member this.CanAddNew : bool
Public ReadOnly Property CanAddNew As Boolean

属性值

Boolean

如果可以将新项添加到集合中，则为 true；否则为 false。

示例

以下示例检查是否可以将项添加到集合中。 如果 CanAddNew 为 false，则示例告知用户无法添加项。 否则，它会显示提示用户添加新项的窗体。 有关整个示例，请参阅 使用 IEditableCollectionView 示例更改集合 。

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

注解

IEditableCollectionView如果存在以下条件，则可以添加新项：

适用于