Question

我通过以下任一代码在运行时将数据库连接到crystal报表，但它在回发中丢失了数据库连接（当我在treeview中单击或尝试导航到下一页时）这是我得到的错误：
System.Runtime.InteropServices.COMException：数据库登录失败。

            ReportDocument cryRpt = new ReportDocument();
            cryRpt.Load(path);

（（（1）））

            for (int i = 0; i < cryRpt.DataSourceConnections.Count; i++)
                cryRpt.DataSourceConnections[i].SetConnection(ServerName, DatabaseName, UserID, Password);
            for (int i = 0; i < cryRpt.Subreports.Count; i++)
                for (int j = 0; j < cryRpt.Subreports[i].DataSourceConnections.Count; j++)
                    cryRpt.OpenSubreport(cryRpt.Subreports[i].Name).DataSourceConnections[j].SetConnection(ServerName, DatabaseName, UserID, Password);

                    cryRpt.OpenSubreport(cryRpt.Subreports[i].Name).DataSourceConnections[j].SetConnection(ServerName, DatabaseName, UserID, Password);

（（（2）））

            crConnectionInfo.ServerName = ServerName;
            crConnectionInfo.DatabaseName = DatabaseName;
            crConnectionInfo.UserID = UserID;
            crConnectionInfo.Password = Password;
            crDatabase = cryRpt.Database;
            crTables = crDatabase.Tables;

            for (int i = 0; i < crTables.Count; i++)
            {
                crTable = crTables[i];
                crTableLogOnInfo = crTable.LogOnInfo;
                crTableLogOnInfo.ConnectionInfo = crConnectionInfo;
                crTable.ApplyLogOnInfo(crTableLogOnInfo);
                //crTable.Location = crConnectionInfo.DatabaseName + ".dbo." + crTable.Location.Substring(crTable.Location.LastIndexOf(".") + 1) 
            }

Answer 1

回发时，CrystalReportViewer正在丢失具有有效连接的报告。

将我在会话中存储cryRpt的行添加到现有报告加载代码中。如下所示，将此组合代码放入仅在初始页面加载时运行的例程：

if (!IsPostBack)
{
    // do all your normal code loading you did in your OP
    // add this line to store the ReportDocument
    Session["myReport"] = cryRpt;
    crReportViewer.ReportSource = cryRpt;
    crReportViewer.Show();
}

然后将此代码放在else中（当我们回发时）从会话中获取ReportDocument并将其重新分配给CrystalReportViewer控件。

else
{
    // this is when you postback
    // (i.e. paging, drilling into tree view, exporting, printing)        
    crReportViewer.ReportSource = (ReportDocument)Session["myReport"];
    crReportViewer.Show();
}

数据库登录失败。在水晶报告中回发后

1 个答案: