CrystalReportViewer forgetting parameters when drilling down

[jf111]

I've got a CrystalReportViewer which is showing a report. I'm passing two parameters to it which change the data. This works, unless you try to drill down into the report further, at which point it resets to the default parameters.

It's a bit like the reportviewer element refreshes itself and forgets everything. I did have a page_init method which attempted to push the values back in but I was getting object reference errors so had probably done it wrong.

What else should I try? Please see code below:

     protected void Page_Load(object sender, EventArgs e)
        {
            if (Session["ReportSource"] != null)
            {
                CrystalReportViewer1.ReportSource = (ReportDocument)Session["ReportSource"];
            }
            else
            {
                ReportDocument reportDocument = new ReportDocument();
                reportDocument.Load(Server.MapPath("~/Report/In Out.rpt"));
                reportDocument.SetDatabaseLogon("user", "pass" ,@"server", "db"); //removed credentials !
                CrystalReportViewer1.ReportSource = reportDocument;
                Session["ReportSource"] = reportDocument;
    
            }
        }
        
        protected void butReport_Click(object sender, EventArgs e)
        {
            ReportDocument reportDocument = new ReportDocument();
            reportDocument.Load(Server.MapPath("./Report/In Out.rpt"));
              reportDocument.SetDatabaseLogon("user", "pass" ,@"server", "db"); //removed credentials !    
            ///Load Session variables with values from web-controls
            Session["@FromDate"] = ConvertToDateTime(Request.Form["StartDate"]);
            Session["@ToDate"] = ConvertToDateTime(Request.Form["EndDate"]);
            reportDocument.SetParameterValue("Start", Session["@FromDate"]);
            reportDocument.SetParameterValue("End", Session["@ToDate"]);
            CrystalReportViewer1.ReportSource = reportDocument;
        }

My CR is embedded as follows

  <div align="center">
                <asp:TextBox ID="StartDate" runat="server" type="date" placeholder="e.g. 31/12/2014" ></asp:TextBox> 
                <asp:TextBox ID="EndDate" runat="server" type="date" placeholder="e.g. 31/12/2014" ></asp:TextBox>
                <asp:button runat="server" id="Submit" type="button" value="Show Report" Text="View Report" onclick="butReport_Click" /></div>
                       
            <div>
    <CR:CrystalReportViewer ID="CrystalReportViewer1" runat="server" 
                       AutoDataBind="True" EnableDatabaseLogonPrompt="False" 
                       GroupTreeImagesFolderUrl="" Height="940px" 
                       ToolbarImagesFolderUrl="" ToolPanelWidth="200px" Width="1411px" 
                       EnableParameterPrompt="False" ReuseParameterValuesOnRefresh="True" 
                       ReportSourceID="CrystalReportSource1" />
                   <CR:CrystalReportSource ID="CrystalReportSource1" runat="server">
                       <Report FileName="Report\In Out.rpt">
                       </Report>
                   </CR:CrystalReportSource>
    </div>

 

[jf111]

Just incase anyone finds this, I fixed it via the following code

protected void Page_Load(object sender, EventArgs e)
{
if (Session["ReportSource"] != null)
CrystalReportViewer1.ReportSource = (ReportDocument)Session["ReportSource"];
}

protected void butReport_Click(object sender, EventArgs e)
{
ReportDocument reportDocument = new ReportDocument();
reportDocument.Load(Server.MapPath("./Report/In Out.rpt"));
reportDocument.SetDatabaseLogon(credentials removed);

///Load Session variables with values from web-controls
Session["@FromDate"] = ConvertToDateTime(Request.Form["StartDate"]);
Session["@ToDate"] = ConvertToDateTime(Request.Form["EndDate"]);
reportDocument.SetParameterValue("Start", Session["@FromDate"]);
reportDocument.SetParameterValue("End", Session["@ToDate"]);
CrystalReportViewer1.ReportSource = reportDocument;
Session["ReportSource"] = reportDocument;
}