动态转换类型对象到类型（某些类）

Question

I would like some of my methods take an Object and convert it in to a useable type:

*Simple example

public void PostAction (object act){
    object Action = (act.GetType) act;
    string ActionName = Action.PostName;
}

From doing a little looking around the internet and Stackoverflow, I have found only ways to call an object's methods without a type

public void PostAction (object act){
    Type t = act.GetType(); // myObject.GetType() would also work
    MethodInfo GetPostName = t.GetMethod("GetPostName");
    GetPostName.Invoke(act, null);
}

Is there a better way? Can I cast a Object to its Type??

Answer 1

You could use dynamic :

public void PostAction (object act){
    ((dynamic)act).GetPostName();
}

But I would go further and change the approach:

1. Declare interface with your GetPostName method:

    public interface IMyInterface { void GetPostName(); } 

2. Implement the interface in your class

3. Change PostAction method to take IMyInterface parameter:

    public void PostAction(IMyInterface act) 

4. Use the interface method withing PostAction method:

    public void PostAction(IMyInterface act) { act.GetPostName(); } 

Benefits:

• would give you a compile-time type safety
• would be faster, because wouldn't require reflection

Answer 2

You should actually never use reflection to invoke a method of an object you pass in. And it is also not really best practice to use object as parameter type of a method. You usually want your code strongly typed.

Anyways, if you want "object" as the type of your parameter, simply cast the object to an interface or type:

    public interface IMyInterface
    {
        string GetPostName();
    }

    public void PostAction(object actObject)
    {
        var action = actObject as IMyInterface;
        if (action != null)
        {
            var postName = action.GetPostName();
        }
    }

If you cast like this, the result can be null if the object does not implement that interface, thats why you might want to check against null...