Delphi连接AutoCAD_计算任意线条的长度宏的嵌套

在AutoCAD里可以通过 List 和Area命令求的样条曲线等任意一条曲线的长度。但是要在delphi得到AutoCAD里任意一条曲线的长度就需要编写宏，然后再将宏嵌入到Delphi里

这是在AutoCAD2004下调试通过的宏

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

这是Delphi里对该宏的嵌入式调用

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;

    Result:=pCadDoc.GetVariable('USERR1');

end;

体会：

       1，宏的语法就是VB的语法。

       2，宏里面的"&"符号就是字符串的连接，在delphi里面就是字符串的相加。比如

            宏里面的 "(setvar " & Chr(34) & "USERR1" & Chr(34) & Chr(32)

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

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

        3 宏里面的VbCr就相当于是按了一下回车键，而在delphi里面就是#13

        4 在delphi里面嵌套宏一定要注意空格和回车。比如在宏里面是"USERR1"，在delphi里  面也必须写成：'USERR1',如果写成'USERR1 '，在连接AutoCAD时就会出线“呼叫被拒绝”，或者是及时在delphi里面能运行通过，你却得不到想要的结果。

         5 关于参数的传递 与函数的调用。

            AutoCAD里提供一个设置系统变量的函数 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

 这个函数在AutoCAD提供的类型库里的原型是这样的：

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

                 理论上这样调用是没有问题的

                           SetVariable('USERR1',1.5);

                但是这样编译能通的过去，运行的时候就会报错“无法设置系统变量值”

                如果声明一个WideString类型的变量就可以了 如：

                           var

                              lName:WideString;

                           lName:='USERR1';

                           SetVariable(lName,1.5);