Delphi鏈接AutoCAD_計算任意線條的長度宏的嵌套

在AutoCAD裏能夠經過 List 和Area命令求的樣條曲線等任意一條曲線的長度。可是要在delphi獲得AutoCAD裏任意一條曲線的長度就須要編寫宏，而後再將宏嵌入到Delphi裏

這是在AutoCAD2004下調試經過的宏

Sub SecFunc()
    Dim SelectionSet As AcadSelectionSet
    Dim lSpLine As AcadSpline
       
    Dim sysVarName As String
    Dim sysVarData As Variant
    Dim DataType As Integer
       
    ThisDrawing.SelectionSets.Item(0).Delete
    Set SelectionSet = ThisDrawing.SelectionSets.Add("New_SelectionSet")
    SelectionSet.SelectOnScreen

    Set lSpLine = SelectionSet.Item(0)
   
    ThisDrawing.SetVariable "USERR1", 1.5
    ThisDrawing.SendCommand "(vl-load-com)" & vbCr
   
    Dim StrCom As String
   
    StrCom = "(setvar " & Chr(34) & "USERR1" & Chr(34) & Chr(32) & "(vlax-curve-getdistatparam (vlax-ename->vla-object (handent " & Chr(34) & lSpLine.Handle & Chr(34) & ")) (vlax-curve-getendparam (vlax-ename->vla-object (handent " & Chr(34) & lSpLine.Handle & Chr(34) & ")))))" & vbCr
    ThisDrawing.SendCommand StrCom
    MsgBox StrCom
    sysVarData = ThisDrawing.GetVariable("USERR1")
    MsgBox sysVarData
End Sub

這是Delphi裏對該宏的嵌入式調用

function GetLengthOfObject(pHandle:THandle;pCadDoc:OleVariant):Real;
var
  lTempVariant:OleVariant;
  lTempVar:wideString;
begin
    lTempVariant:=0;
    lTempVar:='USERR1';
    pCadDoc.SetVariable(lTempVar,lTempVariant);
    lTempVar:='(vl-load-com)' + #13;
    pCadDoc.SendCommand(lTempVar);

    lTempVar:='(setvar ' + Chr(34) + 'USERR1'+Chr(34)+ Chr(32) +
                        '(vlax-curve-getdistatparam (vlax-ename->vla-object '+
                        '(handent '+ Chr(34) +IntToStr(pHandle)+ Chr(34)+')) '+
                        '(vlax-curve-getendparam (vlax-ename->vla-object '+
                        '(handent '+ Chr(34) +IntToStr(pHandle)+Chr(34) +
                        ')))))'+#13;
    pCadDoc.SendCommand(lTempVar);
    Result:=pCadDoc.GetVariable('USERR1');
end;
體會：

       1，宏的語法就是VB的語法。

       2，宏裏面的"&"符號就是字符串的鏈接，在delphi裏面就是字符串的相加。好比

            宏裏面的 "(setvar " & Chr(34) & "USERR1" & Chr(34) & Chr(32)

            在delphi裏面就是"(setvar " + Chr(34) + "USERR1" + Chr(34) + Chr(32)

            其中 Chr(34)是 " 符號 Chr(32)是空字符

        3 宏裏面的VbCr就至關因而按了一下回車鍵，而在delphi裏面就是#13

        4 在delphi裏面嵌套宏必定要注意空格和回車。好比在宏裏面是"USERR1"，在delphi裏  面也必須寫成：'USERR1',若是寫成'USERR1 '，在鏈接AutoCAD時就會出線「呼叫被拒絕」，或者是及時在delphi裏面能運行經過，你卻得不到想要的結果。

         5 關於參數的傳遞 與函數的調用。

            AutoCAD裏提供一個設置系統變量的函數 SetVariable 原型是：

                  object.SetVariable Name, Value

                             Object : Document
                                          The object or objects this method applies to.     

                             Name :String; input-only
                                        The name of the system variable to set.  

                               Value:Variant; input-only
                                         The new value for the specified system variable.    

                  Example

                       

Sub Example_SetVariable()
    ' This example sets various system variables, each of
    ' a different data type.
    
    Dim sysVarName As String
    Dim sysVarData As Variant
    Dim DataType As Integer
    
    ' Set FILEDIA system variable (data type Integer) to 1. NOTE that
    ' you need to declare a variable as the data type of system variable,
    ' assign data to that variable and then make it variant type
    Dim intData As Integer
    sysVarName = "FILEDIA"
    intData = 1
    sysVarData = intData    ' Integer data
    ThisDrawing.SetVariable sysVarName, sysVarData
    
    ' Check the variable using GetVariable
    sysVarData = ThisDrawing.GetVariable(sysVarName)
    MsgBox sysVarName & " = " & sysVarData, , "SetVariable Example"
    
    ' Set DCTCUST system variable (data type String) to "My Custom Dictionary"
    Dim strData As String
    sysVarName = "DCTCUST"
    strData = "My Custom Dictionary"
    sysVarData = strData        ' String data
    ThisDrawing.SetVariable sysVarName, sysVarData
    
    ' Check the variable using GetVariable
    sysVarData = ThisDrawing.GetVariable(sysVarName)
    MsgBox sysVarName & " = " & sysVarData, , "SetVariable Example"
   
    ' Set CHAMFERA system variable (data type Double) to 1.5
    Dim dataDouble As Double
    sysVarName = "CHAMFERA"
    dataDouble = 1.5
    sysVarData = dataDouble ' Double data
    ThisDrawing.SetVariable sysVarName, sysVarData
    ' Check the variable using GetVariable
    sysVarData = ThisDrawing.GetVariable(sysVarName)
    MsgBox sysVarName & " = " & sysVarData, , "SetVariable Example"
   
    ' Set INSBASE system variable (data type array) to (1.0,1.0,0)
    Dim arrayData3D(0 To 2) As Double
    sysVarName = "INSBASE"
    arrayData3D(0) = 1#: arrayData3D(1) = 1#: arrayData3D(2) = 0
    sysVarData = arrayData3D    ' 3D array data
    ThisDrawing.SetVariable sysVarName, sysVarData
    ' Check the variable using GetVariable
    sysVarData = ThisDrawing.GetVariable(sysVarName)
    MsgBox sysVarName & " = " & sysVarData(0) & ", " & sysVarData(1) & ", " & sysVarData(2), , "SetVariable Example"
    
End Sub

 這個函數在AutoCAD提供的類型庫裏的原型是這樣的：

                 procedure SetVariable(const Name: WideString; Value: OleVariant); safecall;

                 理論上這樣調用是沒有問題的

                           SetVariable('USERR1',1.5);

                可是這樣編譯能通的過去，運行的時候就會報錯「沒法設置系統變量值」

                若是聲明一個WideString類型的變量就能夠了 如：

                           var

                              lName:WideString;

                           lName:='USERR1';

                           SetVariable(lName,1.5);