Question

我尝试将下面的代码转换为switch语句，但我的技能在c＃中并不完美。有人可以帮我解决这个案子吗？

protected void logobtn_Click(object sender, ImageClickEventArgs e)
{
    HttpCookie cookie = Request.Cookies.Get("Location");

    if (cookie["Location"] == null || 
        cookie["Location"].ToString() == null || 
        cookie["Location"].ToString() == "" || 
        cookie["Location"].ToString() == "-- Europe and Eastern Europe --" ||
        cookie["Location"].ToString() == "-- Asia & South-East Asia --" || 
        cookie["Location"].ToString() == "-- North & South of America --"
    ) {
        Response.Redirect("Index.aspx");
    } else {
        Response.Redirect(string.Format("Berava.aspx?Country={0}", cookie.Value));
    }
}

Answer 1

如果您使用C＃6

，可以这样做

switch (cookie["Location"]?.ToString()) {
    case null:
    case "":
    case "-- Europe and Eastern Europe --":
    case "-- Asia & South-East Asia --":
    case "-- North & South of America --":
        Response.Redirect("Index.aspx");
        break;
    default:
        Response.Redirect(string.Format("Berava.aspx?Country={0}", cookie.Value));
        break;
}

当?.ToString()为null时，cookie["Location"]内容会返回null。因此，处理这两个条件：

cookie["Location"] == null || 
cookie["Location"].ToString() == null

其他人非常直截了当。我想你可以理解。

IMO，开关看起来不如原来的那样好。在这种情况下，if可能更容易理解。但如果你真的喜欢转换，那也很好。

Answer 2

您可以尝试以下代码：

HttpCookie cookie = Request.Cookies.Get("Location");

            if (cookie["Location"]==null)
                Response.Redirect(string.Format("Berava.aspx?Country={0}", cookie.Value));
else
            switch (cookie["Location"].ToString())
            {
                case null:
                case "":
                case "-- Europe and Eastern Europe --":
                case "-- Asia & South-East Asia --":
                case "-- North & South of America --":    
                    Response.Redirect("Index.aspx");
                    break;
                default:
                    Response.Redirect(string.Format("Berava.aspx?Country={0}", cookie.Value));
                    break;
            }

Answer 3

试试这个，

HttpCookie cookie = Request.Cookies.Get("Location");

        switch (cookie["Location"])
        {
            case null :
            case "":
            case "--Europe and Eastern Europe--" :
            case "-- Asia & South-East Asia --":
            case "-- North & South of America --":
                Response.Redirect("Index.aspx");
                break;
            default:
                Response.Redirect(string.Format("Berava.aspx?Country={0}", cookie.Value));
                break;
        }

Answer 4

我认为你不需要修改你的条件来切换，如果你真的想要你可以使用下面的代码。

 string coo = Convert.ToString(Request.Cookies["Location"]==null?null:Request.Cookies["Location"].Value);
                switch(coo)
                {
                    case null:
                        Response.Redirect("Index.aspx");
                    case "":
                        Response.Redirect("Index.aspx");
                    case "-- North & South of America --":
                         Response.Redirect("Index.aspx");
                    case "-- Asia & South-East Asia --":
                         Response.Redirect("Index.aspx");
                    case "-- Europe and Eastern Europe --":
                         Response.Redirect("Index.aspx");
                    default:
                        Response.Redirect(string.Format("Berava.aspx?Country={0}", coo)); 
}

Answer 5

        var cookie = Request.Cookies.Get("Location")?["Location"];

        switch (cookie)
        {
            case null:
                Response.Redirect("Index.aspx");
                // DO STUFF
                break;
            case "":
                // DO STUFF
                break;
            case "-- Europe and Eastern Europe --":
                // DO STUFF
                break;
            case "-- Asia & South-East Asia --":
                // DO STUFF
                break;
            case "-- North & South of America --":
                // DO STUFF
                break;
            default:
                Response.Redirect(string.Format("Berava.aspx?Country={0}", cookie.Value));
                break;
        }

Answer 6

如果你肯定想要一个案例陈述，那么这应该有效：

HttpCookie cookie = Request.Cookies.Get("Location");

if (cookie != null)
{
    string cookieString = cookie["Location"].ToString();

    switch (cookieString)
    {
        case "":
        case "-- Europe and Eastern Europe --":
        case "-- Asia & South-East Asia --":
        case "-- North & South of America --":
            Response.Redirect("Index.aspx");
            break;
        default:
            Response.Redirect(string.Format("Berava.aspx?Country={0}", cookie.Value));
            break;
    }
}
else
{
    //this is the null case...
    Response.Redirect("Index.aspx");
}

将If语句转换为switch

6 个答案: