Public Function BeginComputeDistance( _
   ByVal MapName As String, _
   ByVal FromPoint As Point, _
   ByVal ToPoint As Point, _
   ByVal Units As esriUnits, _
   ByVal callback As AsyncCallback, _
   ByVal asyncState As Object _
) As IAsyncResult

Dim instance As MapServerProxy
Dim MapName As String
Dim FromPoint As Point
Dim ToPoint As Point
Dim Units As esriUnits
Dim callback As AsyncCallback
Dim asyncState As Object
Dim value As IAsyncResult
 
value = instance.BeginComputeDistance(MapName, FromPoint, ToPoint, Units, callback, asyncState)

public IAsyncResult BeginComputeDistance( 
   string MapName,
   Point FromPoint,
   Point ToPoint,
   esriUnits Units,
   AsyncCallback callback,
   object asyncState
)