VB6+Crystal Report 8.0预览后导出Excel报文件找不到错误求助

I've run into this exact conflict between the CRViewer control (your Crt1 object) and the CRAXDRT automation library before with CR8.0. The issue stems from resource/connection conflicts between the two Crystal Reports object models—the CRViewer doesn't fully release database resources after preview, which messes up the CRAXDRT instance's ability to resolve table locations when you try to export next. Here are the fixes that worked for me, tailored to your 300+ report setup (no version upgrades needed):

Fix 1: Clean Up CRViewer Resources After Preview #

Modify your existing Preview sub to explicitly reset the CRViewer control once the preview window is closed. This ensures it doesn't hold onto stale database connections or report references:

Private Sub Preview()
    Crt1.ReportFileName = "C:\Sample_Report.rpt"
    Crt1.SelectionFormula = ""
    Crt1.DiscardSavedData = True
    Crt1.WindowState = crptMaximized
    Crt1.Action = 1
    
    ' Reset the control after preview closes to release resources
    Crt1.ReportFileName = ""
    Set Crt1.Report = Nothing
End Sub

Fix 2: Strengthen Export Code with Explicit Connection Details #

Your export code was missing critical connection configuration for Access MDBs. CR8.0 needs explicit OLE DB provider details to avoid confusion after preview. Update your Report_ExportToExcel sub to:

• Use the passed ReportPath instead of hardcoding (better for your 300+ reports)
• Explicitly set the OLE DB provider and connection string for each table
• Always create a fresh CRAXDRT.Application instance per export

Private Sub Report_ExportToExcel(ReportPath As String)
    On Error GoTo Loc
    Dim path1 As String
    path1 = Save_Dialog ' Open save dialog to get output path
    If path1 = "" Then Exit Sub
    
    ' Create a fresh CRAXDRT instance to avoid conflicts with CRViewer
    Dim appl As New CRAXDRT.Application
    Dim dbTable As CRAXDRT.DatabaseTable
    Dim rep As CRAXDRT.Report
    
    Set rep = appl.OpenReport(ReportPath, 1)
    rep.DiscardSavedData
    
    ' Update each table's connection explicitly (critical for Access)
    For Each dbTable In rep.Database.Tables
        ' Set logon info: empty username/password for Access, specify MDB path
        dbTable.SetLogOnInfo "", "", "C:\Sample.mdb", ""
        dbTable.Location = "C:\Sample.mdb"
        ' Force the correct Jet OLE DB provider
        dbTable.Connect = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\Sample.mdb;Persist Security Info=False"
    Next
    
    ' Configure export settings
    With rep.ExportOptions
        .DiskFileName = path1
        .DestinationType = crEDTDiskFile
        .ExcelAreaType = crDetail
        .ExcelUseTabularFormat = True
        .ExcelTabHasColumnHeadings = True
        .FormatType = crEFTExcel80Tabular
    End With
    
    rep.Export False
    
    ' Clean up export resources
    Set rep = Nothing
    Set appl = Nothing
    Exit Sub
Loc:
    MsgBox Err.Description
    ' Ensure cleanup even on error
    Set rep = Nothing
    Set appl = Nothing
End Sub

Fix 3: Force CRViewer to Close Before Export (If Needed) #

If the first two fixes don't resolve the issue, add a check to close any active CRViewer preview before starting the export. Add this code right before calling Report_ExportToExcel:

' Ensure CRViewer is not holding a report before exporting
If Not Crt1.Report Is Nothing Then
    Crt1.Close
    Set Crt1.Report = Nothing
    Crt1.ReportFileName = ""
End If

' Now call your export function
Report_ExportToExcel "C:\Sample_Report.rpt"

Why This Works #

CRViewer (used for preview) and CRAXDRT (used for export) share underlying CR8.0 runtime components but run in separate contexts. When you preview a report, CRViewer caches database connection details that can interfere with subsequent CRAXDRT operations. By cleaning up CRViewer resources, using fresh CRAXDRT instances, and explicitly defining connection parameters, you eliminate these conflicts entirely—no need to upgrade your 300+ reports.

内容的提问来源于stack exchange，提问作者RAJ