无法将类型xx隐式转换为“T”

 public static T GetValue<T>(string inValue)
        {
            if (typeof(T) == typeof(Bitmap))
            {
                return (T)(Object)new Bitmap(inValue);
            }
            else
            {
              //一般类型
                return (T)Convert.ChangeType(inValue, typeof(T));
            }
            throw new Exception("");
        }