Freigeben über

CursorRefresh Method

  • Artikel

Refreshes a cursor with current data from the data source. CursorRefresh re-executes the value of the SelectCmd parameter in the BeforeCursorRefresh event with respect to CursorAdapter DataSourceType.

Note

If the SelectCmd parameter in the BeforeCursorRefresh event contains parameters, you can modify the scope of the rows that are returned through the original query by changing the parameters.

CursorAdapter.CursorRefresh()

Return Value

Logical data type. CursorRefresh returns True (.T.) if the cursor is repopulated successfully and False (.F.) if not repopulated successfully.

Note

To retrieve error information when CursorRefresh returns False (.F.), you must call the AERROR( ) function because Visual Foxpro error handling, such as the ON ERROR command, Error event, and TRY...CATCH...FINALLY command, does not capture this error information.

Remarks

Applies To: CursorAdapter Class

CursorRefresh updates the following properties for the ADO or ODBC-based cursor from the following CursorAdapter properties:

Visual FoxPro generates an error message when the cursor contains unsaved changes.

If the CursorAdapter DataSourceType property is "ADO" when executing the CursorAdapter CursorFill method, CursorRefresh behaves in the following manner:

  • CursorAdapter object has an attached cursor resulting from executing SelectCmd using CursorFill:

    • Sets the ADO Command CommandText property for the ADO RecordSet ActiveCommand object to the SelectCmd used to open the ADO RecordSet unless CommandText already contains this value.

    • Refreshes the Command object parameters collection and re-evaluates the parameter values.

    • Calls the ADO RecordSet Requery method and passes the same values in the nOptions parameter used by CursorFill to open the ADO RecordSet.

  • CursorAdapter object has an attached cursor resulting from passing an already open ADO RecordSet to the CursorFill Source parameter.

    • Calls the ADO RecordSet Requery method and pass the same value for the nOptions parameter used by CursorFill.

Note

The CursorRefresh method ignores the MapBinary and MapVarchar properties for mapping data types.

Example

Example 1

The following example illustrates retrieving results using ADO with a parameter and using CursorRefresh to refresh data. The connection string settings for SQL Server (localhost) and Visual FoxPro OLE DB Provider are the following:

* .ConnectionString = 'provider=SQLOLEDB.1;data source=localhost;'+ 
* 'initial catalog=Northwind;trusted_connection=yes'
CLEAR
LOCAL loConn AS ADODB.CONNECTION, ;
   loCommand AS ADODB.COMMAND, ;
   loException AS EXCEPTION, ;
   loCursor AS CURSORADAPTER, ;
   country, ;
   laErrors[1]
loConn = CREATEOBJECT('ADODB.Connection')
WITH loConn
   .ConnectionString = 'provider=vfpoledb;data source=' + ;
   HOME(2)+'northwind\Northwind.dbc'
   TRY
      .OPEN()
   CATCH TO loException
      MESSAGEBOX(loException.MESSAGE)
      CANCEL
   ENDTRY
ENDWITH
loCommand = CREATEOBJECT('ADODB.Command')
loCommand.ActiveConnection = loConn
loCursor = CREATEOBJECT('CursorAdapter')
WITH loCursor
   .ALIAS          = 'Customers'
   .DATASOURCETYPE = 'ADO'
   .SELECTCMD      = ;
   'select * from customers where country=?lcCountry'
   lcCountry       = 'Brazil'
   .DATASOURCE = CREATEOBJECT('ADODB.Recordset')
   .DATASOURCE.ActiveConnection = loConn
   llReturn = .CURSORFILL(.F., .F., 0, loCommand)
   IF llReturn
      BROWSE
      lcCountry = 'Canada'
      llReturn  = .CURSORREFRESH()
      IF llReturn
         BROWSE
      ENDIF llReturn
   ELSE
      AERROR(laErrors)
      MESSAGEBOX(laErrors[2])
   ENDIF llReturn
ENDWITH

The following example that illustrates using CursorRefresh with an already opened ADO Recordset. The connection string settings for SQL Server (localhost) and the Visual FoxPro OLE DB Provider are:

* .ConnectionString = 'provider=SQLOLEDB.1;data source=localhost;' + ;
* 'initial catalog=Northwind;trusted_connection=yes'
CLEAR
LOCAL loConn AS ADODB.CONNECTION, ;
   loCommand AS ADODB.COMMAND, ;
   loParam AS ADODB.PARAMETER, ;
   loRs AS ADODB.Recordset,;
   loException AS EXCEPTION, ;
   loCursor AS CURSORADAPTER, ;
   lcCountry, ;
   laErrors[1]
loConn = CREATEOBJECT('ADODB.Connection')
WITH loConn
   .ConnectionString = 'provider=vfpoledb;data source=' + ;
      HOME(2)+'northwind\Northwind.dbc'
   TRY
      .OPEN()
   CATCH TO loException
      MESSAGEBOX(loException.MESSAGE)
      CANCEL
   ENDTRY
ENDWITH
loCommand = CREATEOBJECT('ADODB.Command')
loCommand.CommandText = ;
   "SELECT * FROM customers WHERE Country = ?"
loParam = loCommand.CreateParameter("Country", 129, 1, 15, "")
loCommand.PARAMETERS.APPEND(loParam)
loCommand.PARAMETERS("Country") = "Brazil"
loCommand.ActiveConnection = loConn
loRs = loCommand.Execute()
loCursor = CREATEOBJECT('CursorAdapter')
WITH loCursor
   .ALIAS          = 'Customers'
   .DATASOURCETYPE = 'ADO'
   llReturn = .CURSORFILL(.F., .F., 0, loRs)
   IF llReturn
      BROWSE
      loRs.ActiveCommand.PARAMETERS("Country") = "Canada"
      llReturn  = .CURSORREFRESH()
      IF llReturn
         BROWSE
      ENDIF llReturn
   ELSE
      AERROR(laErrors)
      MESSAGEBOX(laErrors[2])
   ENDIF llReturn
ENDWITH

See Also

Reference

CursorAdapter Object Properties, Methods, and Events
BeforeCursorRefresh Event

Other Resources

Methods (Visual FoxPro)