请教类型转换的问题

[maotin]

定义了一个基类,如下：

using System;
using System.Collections.Generic;
using System.Data;
using System.Text;

namespace BusinessRules
{
    public interface IBSBase
    {
        DataSet GetAll();
    }
}

添加一个子类，如下：

using System;
using System.Collections.Generic;
using System.Data;
using System.Text;

namespace BusinessRules
{
    public class Class1:IBSBase
    {
        public DataSet GetAll()
        {
            return null;
        }
    }
}

然后在程序中，使用反射创建子类，代码如下：

 Type obj = System.Reflection.Assembly.LoadFile(filePath).GetType("BusinessRules.Class1");
 //该处出现bug,抛出：无法将类型为“BusinessRules.Class1”的对象强制转换为类型“BusinessRules.IBSBase”。
 BusinessRules.IBSBase rules = (BusinessRules.IBSBase)Activator.CreateInstance(obj);

请教这里怎么得到BusinessRules.IBSBase ；我希望能通过反射得到的子类实例转换成基类！
请各位多指教，谢谢!

[lovefootball]

反射时的BusinessRules.IBSBase 和Class1继承的接口是否在同一个DLL？？？

Type t = typeof(BusinessRules.Class1);
BusinessRules.IBSBase rules = Activator.CreateInstance(t) as BusinessRules.IBSBase;
我这样是没问题的~~

[hiddkiller]

BusinessRules.IBSBase rules =(BusinessRules.IBSBase)Activator.CreateInstance(obj);

这样不行吗?

[Dobzhansky]

我这样可以转换

          assembly = Assembly.Load(_assemblyName);// Assembly.LoadFrom(assemblyName);
          _providerInstance = (EcaProvider)assembly.CreateInstance(_providerName);

[Dobzhansky]

[Quote=引用 7 楼 lovefootball 的回复:]
反射时的BusinessRules.IBSBase 和Class1继承的接口是否在同一个DLL？？？

Type t = typeof(BusinessRules.Class1);
BusinessRules.IBSBase rules = Activator.CreateInstance(t) as BusinessRules.IBSBase;
我这样是没问题的~~
[/Quote]

很可能是不同程序集的问题把

[gomoku]

1. The reason is that copying class/interface definition into your projects won't make them the identical type. So you need
to have a common dll that contains the interface (IBSBase.dll).

2. In your Class1 project add reference to IBSBase.dll

3. In your project that Activator.CreateInstance(), add reference to IBSBase.dll.

4. Then it is ok to cast: BusinessRules.IBSBase rules = (BusinessRules.IBSBase)Activator.CreateInstance(obj);

[ilovey4]

不懂 帮顶

[wangxb8888]

路过

[smartkide]

学习中,帮顶.

[Tll_W]

关注一下

[stning]

肯定可以，就as。楼上有人给出解决方案了

[codehunter008]

11楼正解！

[vwxyzh]

[Quote=引用 11 楼 gomoku 的回复:]
1. The reason is that copying class/interface definition into your projects won't make them the identical type. So you need
to have a common dll that contains the interface (IBSBase.dll).

2. In your Class1 project add reference to IBSBase.dll

3. In your project that Activator.CreateInstance(), add reference to IBSBase.dll.

4. Then it is ok to cast: BusinessRules.IBSBase rules = (Busine…
[/Quote]
额外加一条，反射加载的dll要在相同目录，否则即使IBSBase.dll的版本相同也会出现类型不同的情况

[maotin]

[Quote=引用 7 楼 lovefootball 的回复:]
反射时的BusinessRules.IBSBase 和Class1继承的接口是否在同一个DLL？？？

Type t = typeof(BusinessRules.Class1);
BusinessRules.IBSBase rules = Activator.CreateInstance(t) as BusinessRules.IBSBase;
我这样是没问题的~~
[/Quote]
是在同一个dll，命名空间也一致

 //如果这样处理，可以转换成功；
 Type t = typeof(BusinessRules.Class1);
 //如果使用下面这种方式，转换后为null，filePath为dll的路径，pBusinessName="BusinessRules.Class1"
 Type t = System.Reflection.Assembly.LoadFile(filePath).GetType(pBusinessName);
 BusinessRules.IBSBase rules = Activator.CreateInstance(t) as BusinessRules.IBSBase; 

[songyingjian2008]

学习

[_空指针_]

BusinessRules.IBSBase rules = null;
rules = Activator.CreateInstance(obj) as BusinessRules.IBSBase;

[BillMhw]

学习了

[vwxyzh]

出现这个问题，通常是因为Assembly的目录和应用程序的目录不同而导致的

[ws_hgo]

没有用反射
Learning........

[capeyf]

根据楼上的回答我的测试也已经调通了 确实是assmbly虽然是一个dll但是引用的时候却是不一样的

[Java_And_NET]

实 现 接 口 了 吗 ?