ListSourceHelper 类
定义
在实现由 IListSource 接口定义的成员时,由数据源控件使用。Used by data source controls when implementing the members defined by the IListSource interface. 此类不能被继承。This class cannot be inherited.
public ref class ListSourceHelper abstract sealed
public static class ListSourceHelper
type ListSourceHelper = class
Public Class ListSourceHelper
- 继承
-
ListSourceHelper
示例
下面的代码示例演示了实现方法的数据源类的设计模式 IListSource 。The following code example demonstrates the design pattern for a data source class that implements the IListSource methods.
#region Implementation of IDataSource
public virtual DataSourceView GetView(string viewName) {
if (null == view) {
view = new SomeDataSourceView(this);
}
return view;
}
public virtual ICollection GetViewNames() {
ArrayList al = new ArrayList(1);
al.Add(GetView(String.Empty).Name);
return al as ICollection;
}
event EventHandler IDataSource.DataSourceChanged {
add {
((IDataSource)this).DataSourceChanged += value;
}
remove {
((IDataSource)this).DataSourceChanged -= value;
}
}
#endregion
#region Implementation of IListSource
bool IListSource.ContainsListCollection {
get {
return ListSourceHelper.ContainsListCollection(this);
}
}
IList IListSource.GetList() {
return ListSourceHelper.GetList(this);
}
#endregion
#Region "Implementation of IDataSource"
Public Overridable Function GetView(viewName As String) As DataSourceView Implements IDataSource.GetView
If view Is Nothing Then
view = New SomeDataSourceView(Me)
End If
Return view
End Function 'GetView
Public Overridable Function GetViewNames() As ICollection Implements IDataSource.GetViewNames
Dim al As New ArrayList(1)
al.Add(GetView(String.Empty).Name)
Return CType( al, ICollection)
End Function 'GetViewNames
Event DataSourceChanged As EventHandler Implements IDataSource.DataSourceChanged
#End Region
#Region "Implementation of IListSource"
ReadOnly Property ContainsListCollection() As Boolean Implements IListSource.ContainsListCollection
Get
Return ListSourceHelper.ContainsListCollection(Me)
End Get
End Property
Function GetList() As IList Implements IListSource.GetList
Return ListSourceHelper.GetList(Me)
End Function 'IListSource.GetList
#End Region
注解
ListSourceHelper类是一个实用工具类,它提供用于 IListSource 通过数据源控件简化接口的实现。The ListSourceHelper class is a utility class provided to simplify implementation of the IListSource interface by data source controls. 实现 IDataSource 接口但不扩展类的数据源控件 DataSourceControl 可以 ListSourceHelper 在其自身的实现中使用该接口所定义的方法的静态方法 IListSource 。Data source controls that implement the IDataSource interface but do not extend the DataSourceControl class can use the static ListSourceHelper methods in their own implementations of the methods defined by the IListSource interface. 从类扩展的数据源控件 DataSourceControl 会自动继承这些方法实现。Data source controls that extend from the DataSourceControl class inherit these method implementations automatically.
方法
| ContainsListCollection(IDataSource) |
指示指定数据源控件是否包含数据源视图对象的集合。Indicates whether the specified data source control contains a collection of data source view objects. |
| GetList(IDataSource) |
检索数据源对象的 IList 集合。Retrieves an IList collection of data source objects. |