Public Overloads Sub OpenWorkbookAsync( _
   ByVal workbookPath As String, _
   ByVal uiCultureName As String, _
   ByVal dataCultureName As String, _
   ByVal userState As Object _
) 

Dim instance As ExcelService
Dim workbookPath As String
Dim uiCultureName As String
Dim dataCultureName As String
Dim userState As Object
 
instance.OpenWorkbookAsync(workbookPath, uiCultureName, dataCultureName, userState)

public void OpenWorkbookAsync( 
   string workbookPath,
   string uiCultureName,
   string dataCultureName,
   object userState
)