如何解决迟绑定（Late Binding）中激活Main Body的报错问题？

早绑定模式下激活Main Body的代码可正常运行：

Dim partDocument1 As PartDocument        
partDocument1 = CATIA.ActiveDocument
Dim part1 As Part
part1 = partDocument1.Part
Dim bodies1 As Bodies = part1.Bodies
Dim body1 As Body = bodies1.Item("Main Body")
part1.InWorkObject = body1

但迟绑定模式下执行类似代码时，会返回错误：Exception de HRESULT : 0x80020003 (DISP_E_MEMBERNOTFOUND)，迟绑定代码如下：

Dim partDocument1 As Object        
partDocument1 = CATIA.ActiveDocument
Dim part1 As Object
part1 = partDocument1.Part
Dim bodies1 As Object
bodies1  = part1.Bodies
Dim body1 As Object 
body1  = bodies1.Item("Main Body")
part1.InWorkObject = body1

解决方法 #

针对迟绑定的报错问题，可尝试以下几种方案：

• 修正VBA环境的对象赋值语法：
  如果是在VBA中使用迟绑定，对象变量赋值必须添加Set关键字，否则会触发成员找不到的错误。修改后的代码如下：

  Dim partDocument1 As Object        
  Set partDocument1 = CATIA.ActiveDocument
  Dim part1 As Object
  Set part1 = partDocument1.Part
  Dim bodies1 As Object
  Set bodies1  = part1.Bodies
  Dim body1 As Object 
  Set body1  = bodies1.Item("Main Body")
  Set part1.InWorkObject = body1
  

• 用SetInWorkObject方法替代属性直接赋值：
  部分CATIA COM对象的属性在迟绑定时直接赋值会失效，可改用官方提供的SetInWorkObject方法设置工作对象：

  Dim partDocument1 As Object        
  partDocument1 = CATIA.ActiveDocument
  Dim part1 As Object
  part1 = partDocument1.Part
  Dim bodies1 As Object
  bodies1  = part1.Bodies
  Dim body1 As Object 
  body1  = bodies1.Item("Main Body")
  ' 替换属性赋值为方法调用
  part1.SetInWorkObject(body1)
  

• 通过反射显式调用COM成员（.NET环境）：
  若在VB.NET等.NET环境中使用迟绑定，可通过反射的InvokeMember方法显式访问属性和方法，确保正确解析COM成员：

  Imports System.Reflection
  
  Dim partDocument1 As Object = CATIA.ActiveDocument
  Dim part1 As Object = partDocument1.GetType().InvokeMember("Part", BindingFlags.GetProperty, Nothing, partDocument1, Nothing)
  Dim bodies1 As Object = part1.GetType().InvokeMember("Bodies", BindingFlags.GetProperty, Nothing, part1, Nothing)
  Dim body1 As Object = bodies1.GetType().InvokeMember("Item", BindingFlags.InvokeMethod, Nothing, bodies1, New Object() {"Main Body"})
  ' 显式设置InWorkObject属性
  part1.GetType().InvokeMember("InWorkObject", BindingFlags.SetProperty, Nothing, part1, New Object() {body1})
  

内容的提问来源于stack exchange，提问作者El doctor Sertato