[讨论]：关于Variant变量

efan2000

对于一个声明为AcadEntity的对象，当它的属性返回值是Variant（变体）类型时，如果这个值是数组的话，则不能直接引用它当中的某一个值。如

2. 
   
3.   [FONT=courier new]
   
4.     Dim startPoint(0 To 2) As Double
   
5.     Dim endPoint(0 To 2) As Double
   
6.     startPoint(0) = 1#: startPoint(1) = 1#: startPoint(2) = 0#
   
7.     endPoint(0) = 5#: endPoint(1) = 5#: endPoint(2) = 0#
   
8.     Dim lineObj As AcadEntity
   
9.     Set lineObj = ThisDrawing.ModelSpace.AddLine(startPoint, endPoint)
   
10.     MsgBox "Start point = " & lineObj.startPoint(0) & ", " & lineObj.startPoint(1)
    
11.   [/FONT]
    

<br />   [FONT=courier new]<br />     Dim startPoint(0 To 2) As Double<br />     Dim endPoint(0 To 2) As Double<br />     startPoint(0) = 1#: startPoint(1) = 1#: startPoint(2) = 0#<br />     endPoint(0) = 5#: endPoint(1) = 5#: endPoint(2) = 0#<br />     Dim lineObj As AcadEntity<br />     Set lineObj = ThisDrawing.ModelSpace.AddLine(startPoint, endPoint)<br />     MsgBox "Start point = " & lineObj.startPoint(0) & ", " & lineObj.startPoint(1)<br />   [/FONT]<br />

运行程序后，将产生错误。
解决方法：1、声明lineObj对象为AcadLine对象。

2. 
   
3.   [FONT=courier new]
   
4.     Dim startPoint(0 To 2) As Double
   
5.     Dim endPoint(0 To 2) As Double
   
6.     startPoint(0) = 1#: startPoint(1) = 1#: startPoint(2) = 0#
   
7.     endPoint(0) = 5#: endPoint(1) = 5#: endPoint(2) = 0#
   
8.     Dim lineObj As AcadLine
   
9.     Set lineObj = ThisDrawing.ModelSpace.AddLine(startPoint, endPoint)
   
10.     MsgBox "Start point = " & lineObj.startPoint(0) & ", " & lineObj.startPoint(1)
    
11.   [/FONT]
    

<br />   [FONT=courier new]<br />     Dim startPoint(0 To 2) As Double<br />     Dim endPoint(0 To 2) As Double<br />     startPoint(0) = 1#: startPoint(1) = 1#: startPoint(2) = 0#<br />     endPoint(0) = 5#: endPoint(1) = 5#: endPoint(2) = 0#<br />     Dim lineObj As AcadLine<br />     Set lineObj = ThisDrawing.ModelSpace.AddLine(startPoint, endPoint)<br />     MsgBox "Start point = " & lineObj.startPoint(0) & ", " & lineObj.startPoint(1)<br />   [/FONT]<br />

2、创建一临时变量，如：

2. 
   
3.   [FONT=courier new]
   
4.     Dim startPoint(0 To 2) As Double
   
5.     Dim endPoint(0 To 2) As Double
   
6.     startPoint(0) = 1#: startPoint(1) = 1#: startPoint(2) = 0#
   
7.     endPoint(0) = 5#: endPoint(1) = 5#: endPoint(2) = 0#
   
8.     Dim lineObj As AcadLine
   
9.     Set lineObj = ThisDrawing.ModelSpace.AddLine(startPoint, endPoint)
   
10.     Dim tempPoint As Variant
    
11.     tempPoint = lineObj.startPoint
    
12.     MsgBox "Start point = " & tempPoint(0) & ", " & tempPoint(1)
    
13.   [/FONT]
    

<br />   [FONT=courier new]<br />     Dim startPoint(0 To 2) As Double<br />     Dim endPoint(0 To 2) As Double<br />     startPoint(0) = 1#: startPoint(1) = 1#: startPoint(2) = 0#<br />     endPoint(0) = 5#: endPoint(1) = 5#: endPoint(2) = 0#<br />     Dim lineObj As AcadLine<br />     Set lineObj = ThisDrawing.ModelSpace.AddLine(startPoint, endPoint)<br />     Dim tempPoint As Variant<br />     tempPoint = lineObj.startPoint<br />     MsgBox "Start point = " & tempPoint(0) & ", " & tempPoint(1)<br />   [/FONT]<br />

fjw_ok

在未创建对象时你没法知道acadentity是LINE
但创建后知道是LINE了，所以就可看他的
特有属性了！