DataSourceView.CanUpdate 屬性

定義

取得值,指出與目前 DataSourceView 物件關聯的 DataSourceControl 物件是否支援 ExecuteUpdate(IDictionary, IDictionary, IDictionary) 作業。Gets a value indicating whether the DataSourceView object associated with the current DataSourceControl object supports the ExecuteUpdate(IDictionary, IDictionary, IDictionary) operation.

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

屬性值

Boolean

如果支援該作業則為 true,否則為 falsetrue if the operation is supported; otherwise, false. 預設實作會傳回 falseThe default implementation returns false.

範例

下列程式碼範例示範如何 CanUpdate 在擴充類別的類別中,覆寫屬性和 ExecuteUpdate 方法 DataSourceViewThe following code example demonstrates how to override the CanUpdate property and the ExecuteUpdate method in a class that extends the DataSourceView class. 這個程式碼範例是針對類別提供之較大範例的一部分 DataSourceViewThis code example is part of a larger example provided for the DataSourceView class.

// The CsvDataSourceView does not currently
// permit update operations. You can modify or
// extend this sample to do so.
public override bool CanUpdate {
    get {
        return false;
    }
}
protected override int ExecuteUpdate(IDictionary keys, IDictionary values, IDictionary oldValues)
{
    throw new NotSupportedException();
}
   ' The CsvDataSourceView does not currently
   ' permit update operations. You can modify or
   ' extend this sample to do so.
   Public Overrides ReadOnly Property CanUpdate() As Boolean
      Get
         Return False
      End Get
   End Property

   Protected Overrides Function ExecuteUpdate(keys As IDictionary, _
                                              values As IDictionary, _
                                              oldValues As IDictionary) As Integer
      Throw New NotSupportedException()
   End Function 'ExecuteUpdate

End Class

備註

CanUpdate屬性不僅反映資料來源控制項的功能,也會反映目前是否適合執行作業。The CanUpdate property reflects not only a capability of the data source control, but also whether it is currently appropriate to perform an operation. 例如,即使資料繫結控制項支援此作業 ExecuteUpdate ,如果未設定必要的 update 命令或某些其他資料,則屬性會傳回 CanUpdate false ,因為更新作業會失敗。For example, even though a data-bound control supports the ExecuteUpdate operation, if a required update command or some other data is not set, the CanUpdate property returns false, as an update operation would fail.

適用於

另請參閱