ASP.NET MVC+WebForms站点Crystal Reports打印提示内存不足求永久解决方案

我的网站采用ASP.NET MVC + WebForms C# 结合Crystal Reports开发，点击按钮使用Crystal Report打印报表时，会抛出如下错误：

"Not enough memory resources are available to process this command"
该错误每两天就会出现，目前只能通过重新发布站点临时解决，希望找到永久修复方案。

相关代码 #

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        TXTORDERID.Text = Request.QueryString["order_number"].ToString();
        TXTDEPTID.Text = Request.QueryString["deptid"].ToString();
        TXTTESTID.Text = Request.QueryString["testid"].ToString();
        TXTCULTURE.Text = Request.QueryString["Culture"].ToString();
        
        ParameterFields paramFields = new ParameterFields();
        ParameterField paramField = new ParameterField();
        ParameterDiscreteValue paramDiscreteValue = new ParameterDiscreteValue();
        ParameterDiscreteValue paramDiscreteValue1 = new ParameterDiscreteValue();
        ParameterField parameterField1 = new ParameterField();
        ParameterDiscreteValue parameterDiscreteValue1 = new ParameterDiscreteValue();
        ParameterFields parameterFields = new ParameterFields();

        if (Convert.ToInt32(TXTDEPTID.Text) == 7 && Convert.ToInt32(TXTCULTURE.Text) == 1)
        {
            TXTPOSITIVE.Text = Request.QueryString["Positive"].ToString();
        }
        if (Session["UserCustid"] != null && Convert.ToInt32(Session["UserCustid"]) > 0)
        {
            if (Convert.ToInt32(TXTDEPTID.Text) == 1 || Convert.ToInt32(TXTDEPTID.Text) == 2 || Convert.ToInt32(TXTDEPTID.Text) == 3 || Convert.ToInt32(TXTDEPTID.Text) == 4)
            {
                paramField.Name = "@ORDER_ID";
                paramDiscreteValue.Value = TXTORDERID.Text.ToString();
                paramField.CurrentValues.Add(paramDiscreteValue);
                paramFields.Add(paramField);

                paramField = new ParameterField(); // <-- This line is added
                paramDiscreteValue = new ParameterDiscreteValue();  // <-- This line is added
                paramField.Name = "@branch_id";
                paramDiscreteValue1.Value = TXTDEPTID.Text.ToString();
                paramField.CurrentValues.Add(paramDiscreteValue1);
                paramFields.Add(paramField);

                CrystalReportViewer1.ParameterFieldInfo = paramFields;
                CrystalReportViewer1.ReuseParameterValuesOnRefresh = true;
                CrystalReportViewer1.ToolPanelView = CrystalDecisions.Web.ToolPanelViewType.None;
                reportDocument.Load(Server.MapPath("~/RPT/RPTCREDITRESULTS.rpt"));
                CrystalReportViewer1.ReportSource = reportDocument;
                reportDocument.SetDatabaseLogon("admin", "1234");
                var connectionInfo = new ConnectionInfo();
                connectionInfo.ServerName = "desktop";
                connectionInfo.DatabaseName = "DBA";
                connectionInfo.Password = "1234";
                connectionInfo.UserID = "admin";
                connectionInfo.Type = ConnectionInfoType.SQL;
                connectionInfo.IntegratedSecurity = false;
                for (int i = 0; i < CrystalReportViewer1.LogOnInfo.Count; i++)
                {
                    CrystalReportViewer1.LogOnInfo[i].ConnectionInfo = connectionInfo;
                }
                CrystalReportViewer1.Dispose();
            }

            if (Convert.ToInt32(TXTDEPTID.Text) == 0)
            {
                parameterField1.Name = "@ORDER_ID";
                parameterDiscreteValue1.Value = (object)this.TXTORDERID.Text.ToString();
                parameterField1.CurrentValues.Add((ParameterValue)parameterDiscreteValue1);
                parameterFields.Add(parameterField1);

                //ParameterField parameterField2 = new ParameterField();
                //ParameterDiscreteValue parameterDiscreteValue2 = new ParameterDiscreteValue();
                //parameterField2.Name = "@deptid";
                //parameterDiscreteValue2.Value = (object)this.TXTDEPTID.Text.ToString();
                //parameterField2.CurrentValues.Add((ParameterValue)parameterDiscreteValue2);
                //parameterFields.Add(parameterField2);
                this.CrystalReportViewer1.ParameterFieldInfo = parameterFields;
                this.CrystalReportViewer1.ReuseParameterValuesOnRefresh = true;
                this.CrystalReportViewer1.ToolPanelView = ToolPanelViewType.None;
                reportDocument.Load(this.Server.MapPath("~/RPT/RPTCREDITRESULTS.rpt"));
                this.CrystalReportViewer1.ReportSource = (object)reportDocument;
                reportDocument.SetDatabaseLogon("admin", "1234");

                ConnectionInfo connectionInfo = new ConnectionInfo();
                connectionInfo.ServerName = "desktop";
                connectionInfo.DatabaseName = "DBA";
                connectionInfo.Password = "1234";
                connectionInfo.UserID = "admin";
                connectionInfo.Type = ConnectionInfoType.SQL;
                connectionInfo.IntegratedSecurity = false;
                for (int index = 0; index < this.CrystalReportViewer1.LogOnInfo.Count; ++index)
                    this.CrystalReportViewer1.LogOnInfo[index].ConnectionInfo = connectionInfo;
                CrystalReportViewer1.Dispose();
            }
        }
    }
}

错误截图 #

待解决疑问 #

• 曾尝试关闭并释放报表文档对象，但运行报表时始终报错：object reference not set to an instance an object error，请问reportDocument.Close(); 和 reportDocument.Dispose(); 代码应该放在什么位置，才不会触发空引用报错？
• 将服务器注册表中的Printjoblimit值修改为1500，该操作是否正确？

1. 修改PrintJobLimit为1500的操作只能延缓报错时间，不是根本解决方案。该参数控制Crystal Reports允许的最大并行处理任务数，默认值为75，调大后只会拉长内存泄漏积累到上限的周期，最终还是会触发内存不足错误。
2. 你当前代码的核心问题是只释放了CrystalReportViewer对象，没有释放reportDocument对象，Crystal Reports底层大量使用非托管资源，不会被.NET垃圾回收机制自动清理，每次打印都会残留资源，积累到上限就会触发报错。
3. 资源释放的正确位置：不能在Page_Load方法内释放，此时报表还未完成渲染返回给前端，提前释放会直接触发空引用错误。推荐两种释放方式：
   • 第一种：重写页面的OnUnload事件，页面生命周期结束、内容已经返回给客户端后统一释放资源，代码示例：

   protected override void OnUnload(EventArgs e)
   {
       base.OnUnload(e);
       if (reportDocument != null)
       {
           reportDocument.Close();
           reportDocument.Dispose();
           reportDocument = null;
       }
       if (CrystalReportViewer1 != null)
       {
           CrystalReportViewer1.Dispose();
       }
       // 主动触发垃圾回收，加速非托管资源释放
       GC.Collect();
       GC.WaitForPendingFinalizers();
   }
   

   • 第二种：将reportDocument改为局部变量，用using语句包裹，执行完逻辑后自动释放，示例如下：

   // 对应逻辑分支内的代码
   using (ReportDocument reportDocument = new ReportDocument())
   {
       // 原有加载报表、设置参数、绑定数据源、绑定到CrystalReportViewer的逻辑全部放在此处
       reportDocument.Load(Server.MapPath("~/RPT/RPTCREDITRESULTS.rpt"));
       // 其他配置逻辑...
       CrystalReportViewer1.ReportSource = reportDocument;
   }
   

4. 额外优化建议：
   • 尽量简化报表逻辑，移除无用的子报表、冗余字段，查询数据时提前过滤减少单报表返回的数据量，降低单任务内存占用
   • 若站点报表访问并发量较高，可单独部署独立的报表服务进程，避免报表内存泄漏影响主站点业务稳定性

内容的提问来源于stack exchange，提问作者Ziad Adnan