For today, I'll show you a routine that adds a line to modelspace. Here's the main routine:
Public Function AddLine(ByVal pt1 As Geometry.Point3d, ByVal pt2 As Geometry.Point3d) As Boolean
' Get the active document as an object
Dim oDWG As Document = Application.DocumentManager.MdiActiveDocument
' Get the database in the active drawing
Dim oDB As Database = oDWG.Database
' Open a transaction so we can modify the drawing
Dim oTrans As DatabaseServices.Transaction = oDB.TransactionManager.StartTransaction
' Get the block table for the active drawing
Dim oBT As BlockTable = CType(oDB.BlockTableId.GetObject(DatabaseServices.OpenMode.ForRead), BlockTable)
' Get the modelspace block table record
Dim oBTR As BlockTableRecord = CType(oBT(BlockTableRecord.ModelSpace).GetObject(OpenMode.ForWrite), BlockTableRecord)
' Create the new line object
Dim oLine As DatabaseServices.Line = Nothing
' Set our return value to false
Dim retVal As Boolean = False
Try
' Create the new line given the start and end point passed into the function
oLine = New DatabaseServices.Line(pt1, pt2)
' Add the line to the block table
oBTR.AppendEntity(oLine)
' Add the line object to the drawing database
oTrans.AddNewlyCreatedDBObject(oLine, True)
' Close the open transaction (very important)
oTrans.Commit()
' Return true if everything worked
retVal = True
Catch ex As System.Exception
MsgBox(ex.Message, MsgBoxStyle.Information, "Error in AddLine")
Finally
' Clean up the transaction object (very important)
oTrans.Dispose()
End Try
' Return true if everything worked, false if not
Return retVal
End Function
To call this routine, add it to a new vb.net class file. Be sure to reference acdbmgd.dll and acmgd.dll (not copied local) in your project settings and add these five lines at the top of the class file:
Imports Autodesk.AutoCAD
Imports Autodesk.AutoCAD.ApplicationServices
Imports Autodesk.AutoCAD.DatabaseServices
Imports Autodesk.AutoCAD.Geometry
Imports Autodesk.AutoCAD.Runtime
It's good practice to add this to the very top of every file in your project as it will cut down on the number of errors later:
Option Explicit On
Option Strict On
All that's left now is to add a function that will call our AddLine function to create a line in our active drawing.
<CommandMethod("AddLine")> _
Public Sub AddLineToModelSpace()
Try
' Define our first point at 0,0,0
Dim oPt1 As New Point3d(0, 0, 0)
' Define our second point at 5,5,0
Dim oPt2 As New Point3d(5, 5, 0)
' Call the AddLine function, passing it our two defined points
If Not AddLine(oPt1, oPt2) Then Throw New System.Exception("Error calling AddLine.")
Catch ex As System.Exception
MsgBox(ex.Message, MsgBoxStyle.Information, "Error in WoPrj")
End Try
End Sub
If you've copied everything correctly, the program will compile and you can now test out your AddLine function by starting AutoCAD, netloading your DLL and entering AddLine on the command prompt.
