从字符串类名创建实例 [英] Create instance from string class name

问题描述

有没有办法做到这一点?我有一个通过查询字符串传递的类名，我想基于它创建一个新实例.

Is there a way to achieve this? I have a class name that I pass via query string and I want to make a new instance based on that.

我尝试过的:

Private Function Carregar() As Object
    Dim bal = String.Concat("PROTBAL.", Request.QueryString("nomeBAL"))
    Dim ent = Request.QueryString("nomeENT")
    Dim codigo = Request.QueryString("codigo")
    Dim descricao = Request.QueryString("descricao")
    Dim teste = Activator.CreateInstance(Type.GetType(bal))
    Return teste.Listar()
End Function

事情是变量teste总是Nothing.

推荐答案

假设您正确连接类名，这应该有效:

assuming you concat the class name correctly, this should work:

System.Reflection.Assembly.GetExecutingAssembly().CreateInstance(bal)

编辑

如果类型(类)可以/可能在另一个程序集中，那么这有效:

If the type (class) can/may be in another assembly, then this works:

System.Reflection.Assembly.GetAssembly(bal).CreateInstance(bal)

但我不确定这会起作用 eitehr - 我没有注意到名称中的点运算符 - 这是内部类还是命名空间引用?我不认为你可以这样解决内部类.如果你可以在 PROTBAL 上创建一个像 CreateNewThing 这样的方法，你可以去掉所有这些，只用一个 arg 调用该方法来指示你想要的类型(因为 PROTBAL 是已知的).

but I am not sure that will work eitehr - I did not notice the dot operator in the name - is this an internal class or namespace ref? I dont think you can resolve internal classes that way. If you could create a method on PROTBAL like CreateNewThing you could do away with all this and just call the method with an arg to indicate which type you want (since PROTBAL is known).

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