显示pdf CrystalReport vb.net时出错

我有下面的代码 它的功能是使用CrystalReports从屏幕上的报告加载数据

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”类型。

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

注：当我把

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

If #End

工作

我需要这个工作，但在释放模式

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“帮助我”

您可以用

替换
.BinaryWrite（s.ToArray）
。BinaryWrite（CType（会话（“myCrystalReport”）、IO.MemoryStream.ToArray（））

我在下面写了一个例子，我不确定这是否是你想要的，但我希望它能帮助你。对于我来说，这可以让用户使用PDF格式下载/查看Crystal报告

 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 report与这些选项放在会话中（rpt是我的Crystal report）：

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如果我的答案不清楚或不是您想要的答案，请告诉我，我会尽快更新它。

我在以下网站上找到了解决方案：

正如SAP guy所回答的： “这是出于设计，我们从未完全支持导出到MemoryStream。 唯一的选择是不使用MemoryStream，这将不会更改。“

因此，解决方案是将内存流替换为流，并将其发送到字节数组中，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

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在本地运行时，我遇到了类似的问题。不要使用流，而是使用以下内容：

使用（CrystalDecisions.CrystalReports.Engine.ReportDocument oRpt）=
新建ReportDocument（））
{    
Load（Server.MapPath（“../RptFiles/MyCReport.rpt”）；
oRpt.SetDataSource（MyDataSource）；
//…你需要的其他东西，params，等等
Response.Clear（）；
Response.ClearHeaders（）；
oRpt.ExportToHttpResponse（ExportFormatType.PortableDocFormat，Response，false，
“MyReportName”）；
oRpt.Close（）；
}

尝试使用此代码在流中转换：

//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));

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();
        }

以下是完整的代码作为参考：

//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));

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();
        }

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对于那些不使用web服务器并且只需要保存的用户：

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()

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我也有同样的问题。这样对我有用，谢谢。