How to pass data from one page to another page using querystring?

Introduction

Querystring is suffixed with the url of the page separated by “?” (question mark) in the form of key and value. Below code snippet, we have “autoid” and “com” querystring with “8” and “show” value respectively.

ShowDetails.aspx?autoid=8&com=show 

Note: In case we want to pass multiple querystring, they are separated by “&” (Ampersand symbol)

DEFAULT.ASPX

<div>
    <a href="ShowDetails.aspx?autoid=5" title="Show records where AutoId is 5">Show records where AutoId is 5 </a>
    <p><asp:HyperLink ID="hyper1" runat="server" Text="Show Record where AutoID is 8"> </asp:HyperLink> </p>
</div>

DEFAULT.ASPX.CS CODE BEHIND

protected void Page_Load(object sender, EventArgs e)
{
  if (!IsPostBack)
  {
     hyper1.NavigateUrl = "ShowDetails.aspx?autoid=8&com=show";
   }
}
 

In the default.aspx page we have an anchor tag and an asp:HyperLink control with two querystrings.

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SHOWDETAILS.ASPX

<div>
    <asp:DetailsView ID="DetailsView1" runat="server" EnableViewState="false" />
</div>

SHOWDETAILS.ASPX.CS CODE BEHIND

 
protected void Page_Load(object sender, EventArgs e)
{
  if (!IsPostBack)
  {
    if (!string.IsNullOrWhiteSpace(Request.QueryString["autoid"]))
    {
      int autoId = 0;
      int.TryParse(Request.QueryString["autoid"], out autoId);
      if (!autoId.Equals(0))
      {
        GetData(autoId);
      }
    }
    // to get the other querystring do the same
    string command = Request.QueryString["com"];
  }
}
private void GetData(int autoId)
{
   DataTable table = new DataTable();
   // get the connection
   using (SqlConnection conn = new SqlConnection(_connStr))
   {
      // write the sql statement to execute
      string sql = "SELECT AutoId, FirstName, LastName, Age, Active FROM PersonalDetail WHERE AutoId = @AutoId ORDER By AutoId";
      // instantiate the command object to fire
      using (SqlCommand cmd = new SqlCommand(sql, conn))
      {
         // get the adapter object and attach the command object to it
         using (SqlDataAdapter ad = new SqlDataAdapter(cmd))
         {
           SqlParameter prm = new SqlParameter("@AutoId", SqlDbType.Int);
           prm.Value = autoId;
           cmd.Parameters.Add(prm);
           // fire Fill method to fetch the data and fill into DataTable
           ad.Fill(table);
         }
      }
  }
  // specify the data source for the GridView
  DetailsView1.DataSource = table;
  // bind the data now
  DetailsView1.DataBind();
}

On click of the hyperlink on the default.aspx, user is redirected to ShowDetails.aspx page with querystring values. That querystring value is retrieved into the Page_Load event of ShowDetails.aspx and passed to GetData method. GetData method uses ADO.NET to retrieve the values from the database and populates to the DetailsView.

OUTPUT

Notice the status bar where url has “autoid=5” separated by “?”.

Clicking above links show the respective record as shown below

Conclusion

Querystring is the easiest way to pass very small amount of data from one page to another page as it passes through the url of the page. However, as it is exposed to the user via the url, it is not suggested to pass the sensitive information like SSL, DOB, PAN Number etc via querystring. 

Do let me know your feedback or question about this article. Thanks for reading and happy learning.