带有 SaveFileDialog VB.NET 的 STAThreadAttribute

Posted 2023-05-07

【中文标题】带有 SaveFileDialog VB.NET 的 STAThreadAttribute

【英文标题】：STAThreadAttribute with SaveFileDialog VB.NET

【发布时间】：2014-11-18 13:19:02

【问题描述】：

我有一个将 ListView 导出到 Excel 工作表的应用程序，我试图在后台执行此操作，但 SaveFileDialog.showdialog() 中出现错误。这是错误：

发生“System.Threading.ThreadStateException”类型的异常 在 System.Windows.Forms.dll 中，但未在用户代码中处理

附加信息：在进行 OLE 调用之前，必须将当前线程设置为单线程单元 (STA) 模式。确保您的 Main 函数上标记了 STAThreadAttribute。仅当将调试器附加到进程时才会引发此异常。

这是我的代码：

Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
    BackgroundWorker1.RunWorkerAsync()
End Sub

Public Sub saveExcelFile(ByVal FileName As String)
    Try
        Dim xls As New Excel.Application
        Dim sheet As Excel.Worksheet
        Dim i As Integer
        xls.Workbooks.Add()
        sheet = xls.ActiveWorkbook.ActiveSheet
        Dim row As Integer = 1
        Dim col As Integer = 1
        For i = 0 To Me.ListView1.Columns.Count - 1
            sheet.Cells(1, i + 1) = Me.ListView1.Columns(i).Text
        Next
        For i = 0 To Me.ListView1.Items.Count - 1
            For j = 0 To Me.ListView1.Items(i).SubItems.Count - 1
                sheet.Cells(i + 2, j + 1) = Me.ListView1.Items(i).SubItems(j).Text
            Next
        Next

        row += 1
        col = 1

        ' for the header 
        sheet.Rows(1).Font.Name = "Cooper Black"
        sheet.Rows(1).Font.size = 12
        sheet.Rows(1).HorizontalAlignment = Excel.XlVAlign.xlVAlignCenter
        Dim mycol As System.Drawing.Color = System.Drawing.ColorTranslator.Fromhtml("#148cf7")
        sheet.Rows(1).Font.color = mycol
        ' for all the sheet without header
        sheet.Range("a2", "z1000").Font.Name = "Arial"
        sheet.Range("a2", "z1000").Font.Size = 13
        sheet.Range("a2", "z1000").HorizontalAlignment = Excel.XlVAlign.xlVAlignCenter

        sheet.Range("A1:X1").EntireColumn.AutoFit()
        sheet.Range("A1:X1").EntireRow.AutoFit()

        xls.ActiveWorkbook.SaveAs(FileName)
        xls.Workbooks.Close()
        xls.Quit()
    Catch ex As Exception

    End Try
End Sub

Private Sub BackgroundWorker1_DoWork(sender As Object, e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork
     Try

        Dim saveFileDialog1 As New SaveFileDialog
        saveFileDialog1.Filter = "Excel File|*.xlsx"
        saveFileDialog1.Title = "Save an Excel File"
        saveFileDialog1.ShowDialog()
        If saveFileDialog1.FileName <> "" Then
            saveExcelFile(saveFileDialog1.FileName)
        End If

    Catch ex As Exception

    End Try
End Sub

Private Sub BackgroundWorker1_RunWorkerCompleted(sender As Object, e As System.ComponentModel.RunWorkerCompletedEventArgs) Handles BackgroundWorker1.RunWorkerCompleted
    MsgBox("done")
End Sub

【参考方案1】：

您可以将与SaveFileDialog1 相关的所有内容移动到Button3_Click 并将文件名存储在私有变量中，以便以后在BackgroundWorker1_DoWork 中使用。

Private _filename As String

Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
    SaveFileDialog1.Title = "Save Excel File"
    SaveFileDialog1.Filter = "Excel files (*.xls)|*.xls|Excel Files (*.xlsx)|*.xslx"
    SaveFileDialog1.ShowDialog()

    'exit if no file selected
    If SaveFileDialog1.FileName = "" Then
        Exit Sub
    End If

    _filename = SaveFileDialog1.FileName

    BackgroundWorker1.RunWorkerAsync()
End Sub

Private Sub BackgroundWorker1_DoWork(sender As Object, e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork
    ...
    book.SaveAs(_filename)
    ...
End Sub

【讨论】：

究竟是什么不工作？不会建吗？你遇到异常了吗？

如果你看到，我会更改我的代码，我尝试将 savegialog 1.file name 保存在变量中，我有同样的错误:(

但是现在你仍然在做有关 BackgroundWorker1_DoWork 中 SaveFileDialog 的所有事情...

我假设您现在遇到了一个错误，因为您尝试从 BackgroundWorker1_DoWork 访问 ListView1，但您无法从那里访问 UI 控件。

【参考方案2】：

我把这段代码放在加载表单中，一切都很完美：

Control.CheckForIllegalCrossThreadCalls = False