Public Overridable Function OnInitializeDataSource( _
   ByVal dataSource As Object, _
   ByVal isFlyRequest As Boolean, _
   ByVal queryText As String, _
   ByVal startRow As Integer, _
   ByVal endRow As Integer, _
   ByVal rowCount As Integer, _
   ByVal additionalFilters As String, _
   ByVal isDDClicked As Boolean _
) As Boolean

Visual Basic (Usage)	Copy Code
Dim instance As WebCombo Dim dataSource As Object Dim isFlyRequest As Boolean Dim queryText As String Dim startRow As Integer Dim endRow As Integer Dim rowCount As Integer Dim additionalFilters As String Dim isDDClicked As Boolean Dim value As Boolean   value = instance.OnInitializeDataSource(dataSource, isFlyRequest, queryText, startRow, endRow, rowCount, additionalFilters, isDDClicked)

public virtual bool OnInitializeDataSource( 
   object dataSource,
   bool isFlyRequest,
   string queryText,
   int startRow,
   int endRow,
   int rowCount,
   string additionalFilters,
   bool isDDClicked
)

public function OnInitializeDataSource( 
    dataSource: TObject;
    isFlyRequest: Boolean;
    queryText: String;
    startRow: Integer;
    endRow: Integer;
    rowCount: Integer;
    additionalFilters: String;
    isDDClicked: Boolean
): Boolean; virtual; 

public function OnInitializeDataSource( 
   dataSource : Object,
   isFlyRequest : boolean,
   queryText : String,
   startRow : int,
   endRow : int,
   rowCount : int,
   additionalFilters : String,
   isDDClicked : boolean
) : boolean;

public: virtual bool OnInitializeDataSource( 
   Object* dataSource,
   bool isFlyRequest,
   string* queryText,
   int startRow,
   int endRow,
   int rowCount,
   string* additionalFilters,
   bool isDDClicked
) 

public:
virtual bool OnInitializeDataSource( 
   Object^ dataSource,
   bool isFlyRequest,
   String^ queryText,
   int startRow,
   int endRow,
   int rowCount,
   String^ additionalFilters,
   bool isDDClicked
) 

Parameters

dataSource

A reference to the dataSource object.

isFlyRequest

queryText

startRow

endRow

rowCount

additionalFilters

isDDClicked

Return Value

Instead of writing your databinding code in Page_Load event, it is more effective to use InitializeDataSource event as a central place for the WebCombo's databinding code. By using this event, you are automatically taking advantage of the WebCombo's automatic data caching feature.

Note that you don't need to use IsDataCached anymore to query the DataCache status since that the control will automatically check it and only call this event when it needs DataSource. You also don't need to put it under !IsPostBack or other conditions because the event is only fired on first page load, on refresh, or when the cache has been cleared/expired. Additionally, the databinding code has been very simplified so that you don't have to call DataBind after you assign the DataSource as needed by other controls normally.

WebCombo.NET 4.0 introduces you to a new code-less data binding. With this new databinding concept, programming databind web application is very easy, simple and straightforward. There are no codes that required in the page’s code behind. Unlike in the previous version, you do not need to write codes inside InitializeDataSource event which pass the datasource to e.DataSource.

Note that you don't need to use IsDataCached anymore to query the DataCache status since that the control will automatically check it and only call this event when it needs DataSource. You also don't need to put it under !IsPostBack or other conditions because the event is only fired on first page load, on refresh, or when the cache has been cleared/expired. Additionally, the databinding code has been very simplified so that you don't have to call WebCombo.DataBind after you assign the DataSource as needed by other controls normally.

Target Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family, Windows Vista, Windows Server 2008 family

Reference

Tasks

Concepts