ILocateCommandEvents_LocateFilter is not working for second datapoint

Question

Hi folks, 
 I am missing something here. I want to prompt the user to click on a line in 2 different places and collect both datapoints. 
 If I click on text for the first datapoint it correctly says its not a line, however for the second datapoint I can click on anything and it accepts it... help! 
 
 sub main() 
 CommandState.StartLocate New clsLocatePts 
 end sub

' ---------------------------class code --------------------------------------- 
 Option Explicit Implements ILocateCommandEvents 
 Dim Mypoint(1) As Point3d ' holds the data point user provides Dim numPointsPlaced As Long ' number of datapoints placed 
 Private Sub ILocateCommandEvents_Start() Application.ShowCommand "" Application.ShowPrompt "Select first point on line, RESET to exit" numPointsPlaced = 0 End Sub 
 Private Sub ILocateCommandEvents_Accept(ByVal Element As Element, Point As Point3d, ByVal view As view) On Error GoTo err If numPointsPlaced = 0 Then CommandState.StartDynamics Mypoint(0) = Point ' capture first point MsgBox "Point 1 captured" Application.ShowPrompt "Select Second Point on line, RESET to restart" Else CommandState.SetLocateCursor MsgBox "Point 2 captured" Mypoint(1) = Point ' capture second point 
 ' have 2 points time for H/W calc MsgBox "time to calc" 
 CommandState.StartDefaultCommand numPointsPlaced = 0 Exit Sub End If 
 numPointsPlaced = numPointsPlaced + 1 Exit Sub err: MsgBox "Datapoint module error " & err.Number & vbCrLf & err.Description End Sub 
 Private Sub ILocateCommandEvents_LocateFilter(ByVal Element As Element, Point As Point3d, Accepted As Boolean) 
 ' add in line string later 
 If Element.Type = msdElementTypeLine Then Accepted = True Else Accepted = False End If 
 End Sub 
 Private Sub ILocateCommandEvents_LocateFailed() ' ShowStatus "Not a line element" MsgBox "Not a line element" End Sub 
 Private Sub ILocateCommandEvents_Dynamics(Point As Point3d, ByVal view As view, ByVal DrawMode As MsdDrawingMode) 
 End Sub 
 Private Sub ILocateCommandEvents_LocateReset() '???? End Sub 
 Private Sub ILocateCommandEvents_Cleanup() 
 End Sub

Jan Šlegr · Accepted Answer

Hi, 
 I think the problem is not in the code, which only follows tool design. At first, you have to define exactly what your tool workflow will be, in other words what will happen when a user click data or reset mouse button. Simplified version of what you described can be: 
 
 Start the tool. 
 Data point at element: First point is identified. Reset: No action. 
 Data point at element: Second point is identified. Reset: Reject the first point (the tool returns to beginning). 
 Data point anywhere: Acceptance of second point, the tool can finish what should be done. Reset: Reject the second point. 
 
 Such kind of workflow (usually is more complex for real tools) gives you clear picture what event (Locate, Accept etc.) to use to track what user action. In your case I think the solution can be: 
 
 One "state variable" ... you have it already, it's number of placed points. 
 If Locate test is passed (element type = line or line string), increase number of placed points. 
 Test when reset button is clicked and if a point(s) is identified already, decreast number of placed points. 
 If Accept method is called and two points are entered, the tool can do its job. 
 
 It means you will have to move the most of your code from Accept method to Locate method. What is helpful is to set break points to all ILocateCommandEvents methods and to track what is called when. 
 With regards, 
 Jan

sivag · Answer

Hi, 
 In your case, you can use IPrimitiveCommandEvents. 
 Set cursor to Locate in the start event of IPrimitiveCommandEvents. 
 Private Sub IPrimitiveCommandEvents_Start() 
 CommandState.SetLocateCursor 
 End Sub 
 In the Data Point event, locate the element by using the data point and validate it. 
 If it is a valid element, store the data point. 
 Private Sub IPrimitiveCommandEvents_DataPoint(Point As Point3d, ByVal View As View) 
 Dim elm As Element 
 Set elm = CommandState.LocateElement(Point, View, True) 
 If elm Is Nothing Then 
 MsgBox "Pick on Line", vbInformation 
 Exit Sub 
 End If 
 If elm.IsLineElement = False Then 
 MsgBox "Invalid Element", vbInformation 
 Else 
 If ptcount = 1 Then 
 dataPoint1 = Point 
 ptcount = 2 
 Else 
 dataPoint2 = Point 
 '........... 
 '........... 
 End If 
 End If 
 End Sub 
 HTH, 
 Siva