c# - Activator.CreateInstance 失败

Question

我正在使用 Activator.CreateInstance 动态创建一个实例。但是，它说对象在每次尝试时都不能为空。粘贴下面的代码。我做错了什么吗？

有什么问题吗

Activator.CreateInstance

取代传统的 switch/case 语句来确定运行时的对象类型？谢谢。

public abstract  class Base
{
    public abstract void Func();

}
public  class  Derived:Base
{
    public override void Func()
    {
        MessageBox.Show("Derived First");
    }
}

public class Derived2 : Base
{
    public override void Func()
    {
        MessageBox.Show("Derived Second");
    }
}

private void button1_Click(object sender, EventArgs e)
{
    // I was trying to make use of the overladed version 
    // where it takes the Type as parameter.
    BaseClass report = 
       (BaseClass) Activator.CreateInstance(Type.GetType("Derived")); 
    report.Func();
}

Answer 1

来自 Type.GetType 的 typeName 参数的文档:

The assembly-qualified name of the type to get. See AssemblyQualifiedName. If the type is in the currently executing assembly or in Mscorlib.dll, it is sufficient to supply the type name qualified by its namespace.

这意味着您(至少)还需要传递命名空间:

BaseClass report = (BaseClass) Activator.CreateInstance(Type.GetType("YourNamespace.Derived"));