CallByName & ByRef in VB.NET

[迈克揉索芙特]

Public Class Class1
Public Function test(ByRef S1 As String) As String
S1 = "second"
End Function
End Class

In my form I do the following:

Dim myObj As New Class1()
Dim local As String = "first"
Call CallByName(myObj , "test", CallType.Method, local)
MsgBox(local)

The byRef dosent seem to be working when I use it with CallByName. Same code works fine in VB but not in VB.NET.

求解中...

[Iovswety]

Don't use CallByName method

Public Class Class1 
    Public Function test(ByRef S1 As String) As String 
        S1 = "second" 
    End Function 
End Class 

        Dim myObj  As New Class1() 
        Dim local As String = "first" 
        myObj.test(local) 
        MsgBox(local) 

[wuyq11]

CallByName函数，调用对象的指定名称的成员方法
反射就是CallByName的.NET版本
在VB.net中通过反射调用
Dim c as New Class1()
Dim type As Type = c.[GetType]()
Dim methodInfo As MethodInfo = type.GetMethod("test", BindingFlags.Instance Or BindingFlags.NonPublic Or BindingFlags.[Public])
Dim args As Object() = New Object() {""}
Dim result As Object = methodInfo.Invoke(target, args)

[古今多少事]

hehe,100%Copy!No problem.

[贝隆]

啊！！你都有难题啊，帮顶。。。

[tiandiyouwo1]

顶

[迈克揉索芙特]

[Quote=引用 2 楼 wuyq11 的回复:]
CallByName函数，调用对象的指定名称的成员方法
反射就是CallByName的.NET版本
在VB.net中通过反射调用
Dim c as New Class1()
Dim type As Type = c.[GetType]()
Dim methodInfo As MethodInfo = type.GetMethod("test", BindingFlags.Instance Or BindingFlags.NonPublic Or BindingFlags.[Public])
Dim args As Object() = New Object() {""}
Dim result As Object = methodInfo.Invoke(target, args)

[/Quote]
谢谢，果然是大佬。
不过我现在用的就是反射，但有问题如下：
我的程序是基于WCF技术的C/S架构，客户端动态调用服务，用如上Object.Invoke(反射)方法时，服务端的错误信息不能到达客户端。反而CallByName却可以正常返回，但缺点是ByRef时的参数返回值让人头痛。

[迈克揉索芙特]

头发掉一地，问题解决了。
最终还是用的反射，vb.net的CallByName在ByRef参数下有缺陷，不知道算不算一个bug。

至于WCF返回的错误信息，是我的疏忽所致。
错误信息应该从ex.InnerException.Message中获得，而我之前却从ex.Message中获得。
粗心导致走了弯路，不该不该...

[yanlongwuhui]

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