尝试下载 Crystal 报告 PDF 时出错

Question

我正在尝试实施 Crystal 报告到我的项目

我的家庭控制器：

using System;
using System.Collections.Generic;
using System.Data.Entity;
using System.IO;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using Biblioteca.Models;
using CrystalDecisions.CrystalReports.Engine;

namespace Biblioteca.Controllers
{
    public class HomeController : Controller
    {
        private BibliotecaDatabase db = new BibliotecaDatabase();

        public ActionResult Index()
        {
            var totalesviewmodel = new TotalesViewModel();
            totalesviewmodel.MontoCopias = db.AlumnosList.Sum(o => o.Copias);
            totalesviewmodel.MontoImpresiones = db.AlumnosList.Sum(o => o.Impresiones);
            totalesviewmodel.DineroDeposito = db.AlumnosList.Sum(o => o.Deposito);
            totalesviewmodel.DineroSap = db.AlumnosList.Sum(o => o.Sap);
            totalesviewmodel.MontoCopiasMaestro = db.MaestrosList.Sum(o => o.Copias);
            totalesviewmodel.MontoImpresionesMaestro = db.MaestrosList.Sum(o => o.Impresiones);
            return View(totalesviewmodel);
        }

        public ActionResult Reports()
        {
            List<Alumno> allDatos = new List<Alumno>();
            using (BibliotecaEntities dc = new BibliotecaEntities())
            {
                allDatos = dc.Alumnos.ToList();
            }
            return View(allDatos);
        }

        public ActionResult ExportReport()
        {
            List<Alumno> allDatos = new List<Alumno>();
            using (BibliotecaEntities dc = new BibliotecaEntities())
            {
                allDatos = dc.Alumnos.ToList();
            }

            ReportDocument rd = new ReportDocument();
            rd.Load(Path.Combine(Server.MapPath("~/Reports"), "rpt_datos.rpt"));
            rd.SetDataSource(allDatos);

            Response.Buffer = false;
            Response.ClearContent();
            Response.ClearHeaders();

            try
            {
                Stream stream = rd.ExportToStream(CrystalDecisions.Shared.ExportFormatType.PortableDocFormat);
                stream.Seek(0, SeekOrigin.Begin);
                return File(stream, "application/pdf", "DatoList.pdf");
            }
            catch (Exception ex)
            {
                throw;
            }
        }

        public ActionResult Contact ()
        {
            ViewBag.Message = "Your contact page.";

            return View();
        }
    }
}

当我尝试下载报告的 PDF 文件时，我的项目停止在：

rd.SetDataSource(allDatos);

出现此错误：

An exception of type 'System.Reflection.TargetInvocationException' occurred in mscorlib.dll but was not handled in user code

当我点击继续时，我的浏览器显示：

The ObjectContext instance has been disposed and can no longer be used for operations that require a connection.

我做错了什么？

Answer 1

那是因为您在功能代码块的 using 范围之外编写此代码：

rd.SetDataSource(allDatos);

尝试将这些代码行写入 using 代码块，或者如果这不是您的问题，您可以删除 using。

希望对您有所帮助。

Answer 2

天哪，非常感谢，你帮了我大忙！...回答：在代码的最后关闭使用块，如下所示：

using System;
using System.Collections.Generic;
using System.Data.Entity;
using System.IO;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using Biblioteca.Models;
using CrystalDecisions.CrystalReports.Engine;

namespace Biblioteca.Controllers
{
    public class HomeController : Controller
{
    private BibliotecaDatabase db = new BibliotecaDatabase();

    public ActionResult Index()
    {
        var totalesviewmodel = new TotalesViewModel();
        totalesviewmodel.MontoCopias = db.AlumnosList.Sum(o => o.Copias);
        totalesviewmodel.MontoImpresiones = db.AlumnosList.Sum(o => o.Impresiones);
        totalesviewmodel.DineroDeposito = db.AlumnosList.Sum(o => o.Deposito);
        totalesviewmodel.DineroSap = db.AlumnosList.Sum(o => o.Sap);
        totalesviewmodel.MontoCopiasMaestro = db.MaestrosList.Sum(o => o.Copias);
        totalesviewmodel.MontoImpresionesMaestro = db.MaestrosList.Sum(o => o.Impresiones);
        return View(totalesviewmodel);
    }

    public ActionResult Reports()
    {
        List<Alumno> allDatos = new List<Alumno>();
        using (BibliotecaEntities dc = new BibliotecaEntities())
        {
            allDatos = dc.Alumnos.ToList();
        }
        return View(allDatos);
    }

    public ActionResult ExportReport()
    {
        List<Alumno> allDatos = new List<Alumno>();
        using (BibliotecaEntities dc = new BibliotecaEntities())
        {
            allDatos = dc.Alumnos.ToList();


        ReportDocument rd = new ReportDocument();
        rd.Load(Path.Combine(Server.MapPath("~/Reports"), "rpt_datos.rpt"));
        rd.SetDataSource(allDatos);

        Response.Buffer = false;
        Response.ClearContent();
        Response.ClearHeaders();

        try
        {
            Stream stream = rd.ExportToStream(CrystalDecisions.Shared.ExportFormatType.PortableDocFormat);
            stream.Seek(0, SeekOrigin.Begin);
            return File(stream, "application/pdf", "DatoList.pdf");
        }
        catch (Exception ex)
        {
            throw;
        }
    }

    public ActionResult Contact ()
    {
        ViewBag.Message = "Your contact page.";

        return View();
    }
}
  }
  }

尝试下载 Crystal 报告 PDF 时出错

Error trying to download Crystal Report PDF

c#

model-view-controller

asp.net-mvc

entity-framework

crystal-reports