How are Query Strings used to pass data between web pages in ASP.NET?

In ASP.NET, query strings are commonly used to pass data between web pages. They provide a simple and straightforward mechanism to send information from one page to another by appending parameters to the URL.

To pass data using query strings, you typically construct a URL with the desired parameters and navigate to the target page. The target page can then access the query string parameters to retrieve the passed data.

1. Construct the URL with the query string parameters:

   
   
   string url = "TargetPage.aspx?id=123&name=John";
   
   

2. Redirect or navigate to the target page using the constructed URL:

   
   
   Response.Redirect(url);
   
   

3. On the target page (e.g., "TargetPage.aspx"), access the query string parameters to retrieve the passed data. This can be done in the page load event or any other appropriate event or method:

   
   
       protected void Page_Load(object sender, EventArgs e)
       {
           string id = Request.QueryString["id"];
           string name = Request.QueryString["name"];
   
           // Use the retrieved data as needed
           // e.g., display it on the page or perform operations based on the values
       }
   
   

   In the above example, the "TargetPage.aspx" page will be loaded with the query string parameters "id" and "name". The values can be accessed using 'Request.QueryString["parameterName"]', where "parameterName" is the name of the specific query string parameter.

It's important to note that query string values are part of the URL and are visible to users. Therefore, avoid passing sensitive or confidential data through query strings. Additionally, be mindful of input validation and security considerations when working with query string parameters to prevent malicious manipulation or attacks.