Creat a polyline from database
The point/coordinate data being in database, or anywhere outside of AutoCAD should have no impact on how AutoCAD create a polyline (assume it is AcadLWPolyline usually). If you need to write code to do it, just remember to separate the code that somehow obtain the points/coordinates from somewhere, and the code that actually create the polyline (or any AcadEntity, for that matter).
Say, you have a separate code module that handle database access, which has a public function to return a double array, representing coordinates of a polyline, like this:
Public Function GetPolylineCoordinates(dbConnectionString As String) As Variant
Dim coords() As Double
'' use ADO (or DAO) to connect the Access DB and retrieve the data and fill out the variable "coords"
GetPolylineCoordinates = coords
End Function
Then in another module, you can have a macro like this:
Public Sub DrawPolylineFromData()
Dim dbConnection As String
dbConnection = "???????????" '' CnnectionString
Dim coords As Variant
coords=GetPolylineCoordinates(dbConnection)
Dim pl As AcadLWPolyline
Set pl = ThisDrawing.AddLIghtWeightPolyline(coords)
'' set polyline's other properties, if necessary, such as Layer, Color..
pl.Update
End Sub
I assume you do know that to create a polyline, you need AT LEAST 2 points. That is, the coordinate array that is passed to AcadModelSpace.AddLightWeightPolyline() method MUST HAVE at least 4 elements.
In your code, each loop in the For...Next, you obtain 1 point (one x value, one y value), and then you try to create a LWPolyline with this ONLY point. I did not see you have "On Error Resume Next", and wondering why the AddLightWeightPolyline(coords) did not raise exception, as it should.
BTW, this line
If i = npts + 1 Then Exit For
is completely unnecessary: the "For i to npts" already guarantees that the i will not go past npts!
I suspect that the x/y values in the recordset is meant to a single polyline with many vertices, and you use RecordSet filter to get points in order (you may sort the recordset in SQL statement rather than filter the recordset in each For... loop for better performance). If this is the case, code would be something like:
Dim coords() as double
Dim i as Integer
Dim j As Integer
'' Open and get RecordSet
For i = 1 to npts
''Get 1 point
rsPP.Filter = "pt='" & i & "'"
''Add the point's X value and add it to the coordinate array
Redim Preserve coords(j)
coords(j)=rsPP!cx
j = j + 1
''Add the point's Y value and add it to the coordinate array
Redim Preserve coords(j)
coords(j)=rsPP!cy
j = j + 1
Next
'' Now you create a polyline with Vertex/point count = npts
'' with coordinate array with element count = 2 x npts
Set pl = ThisDrawing.AddLightWeightPolyline(coords)
HTH
