c# – 无法将InputEventArgs转换为MouseEventArgs

我正在尝试制作这种扩展方法.在演员说“无法将类型T转换为MouseEventArgs”时出错.我不应该能够向上转换对象(因为MouseEventArgs：InputEventArgs)？

如果你很好奇,我使用它来共享Mouse和Touch事件之间的事件处理程序,只需使用处理程序方法中的基本InputEventArgs.

    public static class InputEventArgsExtensions
    {
        public static Point GetPosition<T>(this T e, IInputElement obj)
            where T : InputEventArgs
        {
            if (e is MouseEventArgs)
                return ((MouseEventArgs)e).GetPosition(obj);
            else if (e is TouchEventArgs)
                return ((TouchEventArgs)e).GetTouchPoint(obj).Position;

            return new Point();
        }
    }

解决方法:

我试过这样做,它对我有用.

    public static class InputEventArgsExtensions
    {
        public static Point GetPosition<T>(this T e, IInputElement obj)
            where T : InputEventArgs
        {
            if (e is MouseEventArgs)
                return (e as MouseEventArgs).GetPosition(obj);
            else if (e is TouchEventArgs)
                return (e as TouchEventArgs).GetTouchPoint(obj).Position;

            return new Point();
        }
    }

标签：c,casting,extension-methods
来源： https://codeday.me/bug/20190704/1372409.html