Question

我有以下代码它的功能是使用CrystalReports从屏幕上的报表加载数据。

Dim strExportFile As String
            strExportFile = "ReportReajustesAplicados.pdf"

            Dim s As System.IO.MemoryStream = relat.ExportToStream(ExportFormatType.PortableDocFormat)
            With HttpContext.Current.Response

                .ClearContent()
                .ClearHeaders()
                .ContentType = "application/pdf"
                .AddHeader("Content-Disposition", "inline; filename=" & strExportFile)
                .BinaryWrite(s.ToArray)
                .End()
            End With

当我提取数据时。

我有以下错误

无法将“FileStreamDeleteOnClose”类型的对象强制转换为“System.IO.MemoryStream”。

我尝试使用System.IO.Stream，提取工作但不会在屏幕上显示数据，因为“.BinaryWrite（s.ToArray）”不接受方法ToArray。

注意：当我把

#if DEBUG Then
             CrystalReportViewer1.ReportSource = relat
             CrystalReportViewer1.DataBind ()
             Exit Sub

If #End

作品

我需要这个才能在发布模式下工作。

帮帮我

Answer 1

我找到了解决方案：

https://archive.sap.com/discussions/thread/3322762

正如SAP回答的那样： “这是设计，我们从未完全支持导出到MemoryStream。唯一的选择是不使用MemoryStream，这不会改变。“

因此，解决方案是将 MemoryStream 替换为 Stream ，并将其发送到 Byte 数组中，如下所示：

Dim strExportFile As String
strExportFile = "ReportReajustesAplicados.pdf"
Dim s As System.IO.Stream = relat.ExportToStream(ExportFormatType.PortableDocFormat)
Dim b(s.Length) As Byte
s.Read(b, 0, CInt(s.Length))

With HttpContext.Current.Response
    .ClearContent()
    .ClearHeaders()
    .ContentType = "application/pdf"
    .AddHeader("Content-Disposition", "inline; filename=" & strExportFile)
    .BinaryWrite(b)
    .Flush()
    .SuppressContent = True
    HttpContext.Current.ApplicationInstance.CompleteRequest()
End With

Answer 2

您可以将.BinaryWrite(s.ToArray)替换为.BinaryWrite(CType(Session("myCrystalReport"), IO.MemoryStream).ToArray())。

我在下面写了一个例子，我不确定这是否是您正在寻找的，但我希望它可以帮助您。这对我来说是允许用户使用PDF格式下载/查看Crystal Reports。

 Dim fileName As String = "ReportReajustesAplicados.pdf"
 Response.ContentType = "application/pdf"
 Response.Clear()
 Response.Buffer = True
 Response.AddHeader("Content-Disposition", "filename=" + fileName)
 Response.BinaryWrite(CType(Session("myCrystalReport"), IO.MemoryStream).ToArray())
 Response.End()

我将Crystal报告放在会话中，包含这些选项（rpt是我的Crystal报告）：

Dim options = rpt.ExportOptions
options.ExportFormatType = CrystalDecisions.Shared.ExportFormatType.PortableDocFormat
Session!myCrystalReport= rpt.FormatEngine.ExportToStream(New CrystalDecisions.Shared.ExportRequestContext With {
        .ExportInfo = options
        })
rpt.Dispose()

如果我的答案不清楚或者不是您要找的，请告诉我，我会尽快更新。

Answer 3

我在本地运行时遇到了类似的问题。而不是使用流，使用此：

using (CrystalDecisions.CrystalReports.Engine.ReportDocument oRpt =
    new ReportDocument())    
{    
    oRpt.Load(Server.MapPath("../RptFiles/MyCReport.rpt"));   
    oRpt.SetDataSource(MyDataSource);  

    // ... other stuff you need, params, etc  

    Response.Clear();                  
    Response.ClearHeaders();

    oRpt.ExportToHttpResponse(ExportFormatType.PortableDocFormat, Response, false,
        "MyReportName");

    oRpt.Close();    
}

Answer 4

尝试使用此代码进行转换：

//MemoryStream oStream = (MemoryStream)reportDocument.ExportToStream(type);
System.IO.Stream oStream = null;
byte[] byteArray = null;
oStream = reportDocument.ExportToStream(type);
byteArray = new byte[oStream.Length];
oStream.Read(byteArray, 0, Convert.ToInt32(oStream.Length - 1));

以下是完整的代码作为参考：

private void ShowReports(ReportDocument reportDocument, string fileName)
        {
            string rptType = GetQsSValue("ReportType");
            ExportFormatType type = ExportFormatType.PortableDocFormat;
            string rptTypeExt = string.Empty;
            string contentType = string.Empty;

            if (rptType == null || rptType == "PDF")
            {
                type = ExportFormatType.PortableDocFormat;
                rptTypeExt = ".pdf";
                contentType = "application/pdf";
            }
            else if (rptType == "Excel" || rptType == "Text")
            {
                type = ExportFormatType.Excel;
                rptTypeExt = ".xls";
                contentType = "application/excel";               
            }

            //MemoryStream oStream = (MemoryStream)reportDocument.ExportToStream(type);
            System.IO.Stream oStream = null;
            byte[] byteArray = null;
            oStream = reportDocument.ExportToStream(type);
            byteArray = new byte[oStream.Length];
            oStream.Read(byteArray, 0, Convert.ToInt32(oStream.Length - 1));

            reportDocument.Close();
            reportDocument.Dispose();
            reportDocument = null;

            HttpContext.Current.Response.Clear();
            HttpContext.Current.Response.Buffer = true;
            HttpContext.Current.Response.ContentType = contentType;
            HttpContext.Current.Response.AddHeader("Content-Disposition", "attachment;filename=" + fileName + rptTypeExt);
            //HttpContext.Current.Response.BinaryWrite(oStream.ToArray());
            HttpContext.Current.Response.BinaryWrite(byteArray);
            HttpContext.Current.Response.Flush();
            HttpContext.Current.Response.Close();
            HttpContext.Current.Response.End();
            GC.Collect();
        }

Answer 5

对于那些不使用Web服务器但只需要保存它的人：

Dim myStream As New System.IO.MemoryStream

'ExportToStream acutally produces type: FileStreamDeleteOnClose -- not Stream.  Can't implicitly convert it to MemoryStream   
Dim myTempStream As System.IO.Stream
myTempStream = oRpt.ExportToStream(CrystalDecisions.Shared.ExportFormatType.PortableDocFormat)

'Now copy the data to a MemoryStream before closing the report and destroying the stream.
myTempStream.CopyTo(myStream)

'Clean up and close the temp stream and report.
oRpt.Close()

错误显示pdf CrystalReport vb.net

5 个答案: