ListSourceHelper Class
Definition
Important
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Used by data source controls when implementing the members defined by the IListSource interface. This class cannot be inherited.
public ref class ListSourceHelper abstract sealed
public static class ListSourceHelper
type ListSourceHelper = class
Public Class ListSourceHelper
- Inheritance
-
ListSourceHelper
Examples
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
Remarks
The ListSourceHelper class is a utility class provided to simplify implementation of the IListSource interface by data source controls. 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. Data source controls that extend from the DataSourceControl class inherit these method implementations automatically.
Methods
ContainsListCollection(IDataSource) |
Indicates whether the specified data source control contains a collection of data source view objects. |
GetList(IDataSource) |
Retrieves an IList collection of data source objects. |