转到下一页时，Crystal Report数据库登录失败错误

Question

I have a Asp.net Form with Crystal Report Viewer Control on It.

On Page_Load Event, I am loading a report & setting a DataSource To it from Database.

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        DataTable dt=  Custom.StaticGeneral.GetDataTable("Select  top 100 * From CustVend order by Code desc");
        dt.TableName = "CustVend";
        dt.AcceptChanges();

        DataSet ds = new DataSet();
        ds.Tables.Add(dt);
        ds.AcceptChanges();


        ReportDocument myReportDocument;
        myReportDocument = new ReportDocument();

        myReportDocument.Load(Server.MapPath("CrystalReport1.rpt"));

        myReportDocument.SetDataSource(ds);
        CrystalReportViewer1.ReportSource = myReportDocument;
        //CrystalReportViewer1.DataBind(); Also Tried This 

        CrystalReportViewer1.DisplayToolbar = true;
    }
}

this is the relevant html

<CR:CrystalReportViewer ID="CrystalReportViewer1" runat="server" 
            GroupTreeImagesFolderUrl="" Height="1202px" 
            ReuseParameterValuesOnRefresh="True" EnableDatabaseLogonPrompt="false"
            ToolbarImagesFolderUrl="" ToolPanelWidth="200px" Width="1104px" />

I have set EnableDatabaseLogonPrompt="false" because I am providing my own data source & question of log in does not arise.

I get to see the Report when Page is Loaded with my data. However, When I Select "Go To Next Page" Link of the crystal report Viewer Control, An Error Pops Up as

Error : "Database logon failed."

Seems that I am missing out something (probably rebinding the dataset/Report) but can't figure it out...

I can solve this error by commenting out the Line if (!IsPostBack). but is it the right way to query the Database again & load the whole report every time user is changing a page ?

Or are there Simpler/easier options available..

Answer 1

The code that loads the report must be execute on every postback. Page_Init is the right place where you can put this code (Page_Load can cause some errors).

Hey, it's reccomended to close ReportDocument on every page unload; this avoid an uncontrolled increase on a Report Counter that will stop the application

 protected void Page_Unload(object sender, EventArgs e)
   {
      if (reportDocument != null)
      reportDocument.Close();
   }

Answer 2

Put the code in LoadData method that should be called if(!IsPostBack). IsPostBack is used for Ajax calls and it's not the case for CrystalReports.

Here is how I do it:

<CR:CrystalReportSource ID="CrystalReportSource1" runat="server">
        <Report FileName="myCristalReport.rpt"></Report>
</CR:CrystalReportSource>

<CR:CrystalReportViewer 
                        ID="CrystalReportViewer1" 
                        runat="server" 
                        AutoDataBind="true"
                        EnableDatabaseLogonPrompt="False" 
                        EnableParameterPrompt="False" 
                        ReportSourceID="CrystalReportSource1" 
                        ToolPanelView="None" />

and in LoadData :

 var reportSource = (CrystalReportSource)this.FindControlRecursively("CrystalReportSource1");
     reportSource.ReportDocument.SetDatabaseLogon("dbuser", "dbpassword");
     reportSource.ReportDocument.SetParameterValue("Month", 2);

....