CURRENT-QUERY( ) method

The handle to the ProDataSet query that contains the currently selected row in the ProBindingSource. This method enables access to the correct child query when a bound .NET grid edits, creates, or deletes a row from a child table.

Use this method when the .NET control is bound to a ProDataSet object that contains child buffers.

Data type:

HANDLE

Access:

Read-only

Applies to:

Data-relation object handle

 

Syntax 

CURRENT-QUERY ( [ band-index ] )

band-index

An optional integer value that specifies the band index in a hierarchical grid. The band index is a 0-based index. Use this parameter only with recursive data-relations. If you specify this parameter for a non-recursive data-relation, the AVM raises an error.

When a .NET control binds to a ProBindingSource that uses a ProDataSet as its data source object, multiple relations for the same parent-child relationship might be presented to the user simultaneously. When the user first expands a parent row in the bound .NET control, the ProBindingSource creates a new child query and displays all child rows for that parent row. The ProBindingSource uses the ProDataSet object’s data-relation query to create and maintain this unique query for all child rows related to the expanded parent row.

Note:

You cannot set this query handle or modify the query.

The following code fragment shows an event handler. The event handler accepts information from a bound UltraWinGrid displaying Order and Orderline data through the grid’s extended version of the .NET System.EventArgs class. From that information, the event handler can find the correct query for the currently selected record.

 

DEFINE VARIABLE hDataSet AS HANDLE NO-UNDO.   ...   PROCEDURE BeforeRowUpdate:   DEFINE INPUT PARAMETER sender AS System.Object         NO-UNDO.   DEFINE INPUT PARAMETER args   AS     Infragistics.Win.UltraWinGrid.CancelableRowEventArgs NO-UNDO.     DEFINE VARIABLE cBufferName AS CHARACTER NO-UNDO.   DEFINE VARIABLE hRelation   AS HANDLE    NO-UNDO.   DEFINE VARIABLE hQuery      AS HANDLE    NO-UNDO.     cBufferName = args:Row:Band:Key.   IF cBufferName EQ "ttOrder" THEN     ASSIGN       hRelation = hDataSet:GET-RELATION(1)       hQuery    = hRelation:CURRENT-QUERY.   END.   ELSE IF cBufferName EQ "ttOrderLine" THEN     ASSIGN       hRelation = hDataSet:GET-RELATION(2)       hQuery    = hRelation:CURRENT-QUERY.   END. END PROCEDURE.

When a ProBindingSource is attached to a ProDataSet with a recursive data-relation, the code above does not work because a single buffer is associated with multiple BandIndexes in a hierarchical grid. The event handler must specify the BandIndex of the current row to determine the correct query.

The following example shows a similar event handler using the optional parameter. Because an employee might also be a manager and have employees of his own, dsRecursive has a recursive data-relation between EmpName and Manager. For the top band of the hierarchy, the event handler can use the TOP-NAV-QUERY. For lower bands, it needs the optional parameter to determine the correct query.

 

DEFINE TEMP-TABLE ttEmp NO-UNDO   BEFORE-TABLE ttEmpB   FIELD EmpName    AS CHARACTER   FIELD Manager    AS CHARACTER   FIELD HireDate   AS INTEGER   INDEX idxEmpName AS UNIQUE EmpName. DEFINE DATASET dsRecursive FOR ttEmp   DATA-RELATION r1 FOR ttemp, ttemp   RELATION-FIELDS(EmpName,Manager) RECURSIVE. DEFINE VARIABLE hRelation AS HANDLE NO-UNDO. DEFINE VARIABLE hTopQuery AS HANDLE NO-UNDO.   ...   PROCEDURE BeforeRowUpdate:   DEFINE INPUT PARAMETER sender AS System.Object         NO-UNDO.   DEFINE INPUT PARAMETER args   AS     Infragistics.Win.UltraWinGrid.CancelableRowEventArgs NO-UNDO.   DEFINE VARIABLE bandIndex     AS INTEGER               NO-UNDO.   DEFINE VARIABLE hQuery        AS HANDLE                NO-UNDO.     ASSIGN     bandIndex = args:Row:Band:Index     hRelation = DATASET dsRecursive:GET-RELATION(1).     IF bandIndex EQ 0 THEN     hQuery = hTopQuery.   ELSE IF bandIndex > 0 THEN     hQuery = hRelation:CURRENT-QUERY(bandIndex). END PROCEDURE.

See also:

BandIndex property