Question

I got an error when trying to get the value of Int32.Parse(Request.QueryString["PLCID"].ToString()) in the thread method and i tried to use parameterizedthread but faild

here my code snippet

protected void btnReqConfirm_Click(object sender, EventArgs e)
{
    Int32 val = Int32.Parse(Request.QueryString["PLCID"].ToString());
    id = Guid.NewGuid();

    ThreadStart ts = new ThreadStart(longRunningProcess);
    Thread th = new Thread(ts);
    th.Start();

    Response.Redirect("Status.aspx?ID="+id.ToString());
}
protected void longRunningProcess()
{
    String _MachineName = String.Empty;
    _MachineIP = String.Empty;
    DBLayer.getMachineByPLCID(Int32.Parse(Request.QueryString["PLCID"].ToString()), out _MachineName, out _MachineIP);

    if (DBLayer.insertRequest(User.Identity.Name, DBLayer.getMachineID(_MachineName), Convert.ToDateTime(lblReqFromVal.Text), Convert.ToDateTime(lblReqToVal.Text)))
    {
        _PLCName = DBLayer._getPlCByID(Int32.Parse(Request.QueryString["PLCID"].ToString()));

        //stop mail now
        LogicLayer.AddNewListItem("Confirmation Mail", "You can initiate your session directly from this link : " + string.Format(@"http://IP/RRRProject/DirectSessionPage.aspx?Machine={0}", _MachineIP), (User.Identity.Name).Substring(5) + "@invensys.com");
        lblConfirmationMessage.Visible = true;
        lblConfirmationMessage.ForeColor = Color.Green;

        Thread.Sleep(9000);
        SimpleProcessCollections.Add(id, "Some result.");
    }
}

any idea??

Answer 1

I suppose that the new Thread is not tied to the same HttpContext of the first one; a Request.QueryString call is a call to HttpContext.Current.Request.QueryString so ts won’t see the parameters of your webapplications.

Anyway, you can pass the QueryString to the Thread and use it. Look at the code sample.

protected void btnReqConfirm_Click(object sender, EventArgs e)
{
 ...
   ThreadStart ts = new ThreadStart(longRunningProcess(Request.QueryString));
 ...
}

protected void longRunningProcess(NameValueCollection queryString)
{
 ...

    _PLCName = DBLayer._getPlCByID(Int32.Parse(queryString["PLCID"].ToString()));
 ...
}