在cookie中存储和检索数据 [英] store and retrieve data in cookie

问题描述

嗨..

我在第1页有一个下拉列表。我选择了我想要的项目，然后点击go ..它将我带到下一页（第2页）并获取结果。 。当我回到第1页时，下拉列表显示默认值而不是我选择的那个。当我退出我的应用程序并登录时，同样的事情发生。我想要的是下拉列表应该显示相同的内容直到我选择的值，除非我关闭浏览器。我已经将下拉列表存储在cookie中。但是当我注销登录到我的应用程序或者当我去其他页面时，我有点担心如何填充它回到我已经给出条件的页面。这就是我所做的事情





HttpCookie myCookie = new HttpCookie（" MyTestCookie"）;

DateTime now = DateTime.Now;



//设置cookie值。

myCookie.Value = now.ToString（）;

//设置cookie过期日期。

myCookie.Expires = n ow.AddYears（50）; //对于一个有效永不过期的cookie



//添加cookie。

Response.Cookies.Add（myCookie）;



Response.Write（"< p>已写入cookie。）;





//读取饼干



HttpCookie myCookie =新的HttpCookie（MyTestCookie）;

myCookie = Request.Cookies [" MyTestCookie"];



//读取cookie信息并显示它。

if（myCookie！= null ）

Response.Write（"< p>" + myCookie.Name +"< p>" + myCookie.Value）;

else

Response.Write（未找到）;

Hi..
I have a dropdownlist in page1.I select the item that I want and click on go..It takes me to the next page(page2) and gets me the result..Again when I come back to page 1 the dropdownlist shows the default value and not the one which I selected..The same thing happens when I log out of my application and logs in..all that I wanted is dropdownlist should show the same value which I selected until and unless I close the browser.i have stored the dropdownlist in cookie..But I''m bit worried how to populate it when I log out nd login to my application or when i go some other page and come back to the page where I have given the condition..this is what I have done


HttpCookie myCookie = new HttpCookie("MyTestCookie");
DateTime now = DateTime.Now;

// Set the cookie value.
myCookie.Value = now.ToString();
// Set the cookie expiration date.
myCookie.Expires = now.AddYears(50); // For a cookie to effectively never expire

// Add the cookie.
Response.Cookies.Add(myCookie);

Response.Write("<p> The cookie has been written.");


//Read cookie

HttpCookie myCookie = new HttpCookie("MyTestCookie");
myCookie = Request.Cookies["MyTestCookie"];

// Read the cookie information and display it.
if (myCookie != null)
Response.Write("<p>"+ myCookie.Name + "<p>"+ myCookie.Value);
else
Response.Write("not found");

推荐答案

在创建cookie之前，您需要检查具有tat name的cookie是否已经退出或者没有。现在你正在创建cookie而不检查它是否已经存在于客户端。这意味着每次都会覆盖你的cookie值。

把你的代码放在这样的：

Before creating cookie you need to check whether that cookie with tat name already exits or not.Right now you are creating cookie without checking whether it is already there in client side. thats mean ur cookie value get override each time.
Put ur code like this:

HttpCookie myCookie = new HttpCookie("MyTestCookie");
 myCookie = Request.Cookies["MyTestCookie"];

 // Check for cookie already present
 if (myCookie != null)
 Response.Write("Cookie is already there.");
 else
{
//create cookie

HttpCookie myCookie = new HttpCookie("MyTestCookie");
 DateTime now = DateTime.Now;
  
 // Set the cookie value.
 myCookie.Value = now.ToString();
 // Set the cookie expiration date.
 myCookie.Expires = now.AddYears(50); // For a cookie to effectively never expire
  
 // Add the cookie.
 Response.Cookies.Add(myCookie);
  
 Response.Write("The cookie has been written.");
}

Ur读取cookie代码与你已经写过的相同

希望这能帮到你。

Ur reading cookie code remains same as u hav written already
hope this helps u out.

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