[drilli]

I am having a problem with redirecitng while using session variables.

In my Produktet.aspx page is this code:

protected void Page_Load(object sender, EventArgs e)
        {
            
            if (!IsPostBack)
            {
                
                IDKat = int.Parse(Request.QueryString["ID_Kategoria"]);
                Session["ID_Kateg"] = IDKat;
           }
        }

From this page i go to DetajetEProduktit.aspx page and after doing something there and clicking a linkButton (in button_click event i try to redirect to Produktet.aspx page but than my sesion variable is lost).

here is the button click event:

 protected void lnkbKtheu_Click(object sender, EventArgs e)
        {
            string url = "~/Produktet.aspx?ID_Kategoria = " + Session["ID_Kateg"] ;
            Response.Redirect(url);
        }

I tried this : Respnse.Redirect(url,false) but it doesn`t work.

Does anyone know the solution?

[Nakor]

Session returns an object, you may need to convert it to a string or back to its original type which was an integer.

[drilli]

I tried this also but it`s the same problem again

protected void lnkbKtheu_Click(object sender, EventArgs e)
        {
            string url = "~/Produktet.aspx?ID_Kategoria = " + int.Parse( HttpContext.Current.Session["ID_Kateg"].ToString()) ;
            Response.Redirect(url,false);
        }

[keakTheGEEK]

That's not going to work either because you are concatenating your url string to an int (int.parse returns an int).

Try using the Convert.ToString() function:

protected void lnkbKtheu_Click(object sender, EventArgs e)
{
    string url = "~/Produktet.aspx?ID_Kategoria = " + Convert.ToString(Session["ID_Kateg"]);
    Response.Redirect(url,false);
}

You could also use a Nullable int in this scenario as well:

protected void lnkbKtheu_Click(object sender, EventArgs e)
{
    int? ID_Kateg = Session["ID_Kateg"] as int?;
    if (ID_Kateg.HasValue) 
    {
        string url = "~/Produktet.aspx?ID_Kategoria = " + ID_Kateg.ToString();   
        Response.Redirect(url,false);
    }
    else 
    {
        //Do something else
    }
}

[drilli]

I tried both of them but still the same problem...there is a null value in session after redirecting.I don`t know what to do.

[drilli]

and here is the Error :


Value cannot be null.
Parameter name: String

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.ArgumentNullException: Value cannot be null.
Parameter name: String

Source Error:


Line 32:
Line 33: PopulateMenu();
Line 34: IDKat = int.Parse(Request.QueryString["ID_Kategoria"]);
Line 35: Session["ID_Kateg"] = IDKat;
Line 36: //int.Parse(Request.QueryString["ID_Kategoria"]);

Source File: C:\Documents and Settings\Refresh\My Documents\Visual Studio 2008\Projects\PorositOnline\PorositOnline\Produktet.aspx.cs Line: 34

Stack Trace:


[ArgumentNullException: Value cannot be null.
Parameter name: String]
System.Number.StringToNumber(String str, NumberStyles options, NumberBuffer& number, NumberFormatInfo info, Boolean parseDecimal) +7467290
System.Number.ParseInt32(String s, NumberStyles style, NumberFormatInfo info) +119
System.Int32.Parse(String s) +23
PorositOnline.Produktet.Page_Load(Object sender, EventArgs e) in C:\Documents and Settings\Refresh\My Documents\Visual Studio 2008\Projects\PorositOnline\PorositOnline\Produktet.aspx.cs:34
System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +14
System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +35
System.Web.UI.Control.onload(EventArgs e) +99
System.Web.UI.Control.LoadRecursive() +50
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +627

Version Information: Microsoft .NET Framework Version:2.0.50727.3053; ASP.NET Version:2.0.50727.3053

[drilli]

Thanks All for your help.Now it is everything OK.It is working