除非首先出现 MsgBox，否则数据不会保存到 Excel 文件

Question

谁能解释为什么我的代码不允许我将数据保存到 Excel，除非我包含 MsgBox？

这是我的代码：

Sub createreport()
        Try
            Dim XA As New Excel.Application
            Dim wb As Excel.Workbook
            Dim ws As Excel.Worksheet
            wb = XA.Workbooks.Open(dataDirectory + "employee_info\dtr_emp.xlsx", False, False, True)
            ws = wb.Worksheets("Sheet1")

            MsgBox("Test") '<---- THIS IS THE MSGBOX I WAS TALKING ABOUT

            For i As Integer = 0 To Me.EmployeeInfoDataGridView.Rows.Count - 1
                Dim DGV As DataGridViewRow = Me.EmployeeInfoDataGridView.Rows(i)
                ws.Cells(7 + i, 1) = DGV.Cells(0).Value
                ws.Cells(7 + i, 2) = DGV.Cells(1).Value
                ws.Cells(7 + i, 3) = DGV.Cells(2).Value
                ws.Cells(7 + i, 4) = DGV.Cells(3).Value
                ws.Cells(7 + i, 5) = DGV.Cells(4).Value
                ws.Cells(7 + i, 6) = DGV.Cells(5).Value
                ws.Cells(7 + i, 7) = DGV.Cells(6).Value
                ws.Cells(7 + i, 8) = DGV.Cells(7).Value
                ws.Cells(7 + i, 9) = DGV.Cells(8).Value
                ws.Cells(7 + i, 10) = DGV.Cells(9).Value
                ws.Cells(7 + i, 11) = DGV.Cells(10).Value
                ws.Cells(7 + i, 12) = DGV.Cells(12).Value
                ws.Cells(7 + i, 13) = DGV.Cells(14).Value
            Next
            XA.Visible = False

            wb.SaveAs(dataDirectory + "employee_info\temp_" + Form1.lbl_date.Text + ".xlsx")
            wb.Close(True)
            XA.Quit()
            wb = Nothing : ws = Nothing : XA = Nothing
            Try
                My.Computer.FileSystem.CopyFile("employee_info\temp_" + Form1.lbl_date.Text + ".xlsx", "employee_info\employee_infos.xlsx", True)
                My.Computer.FileSystem.DeleteFile("employee_info\temp_" + Form1.lbl_date.Text + ".xlsx", FileIO.UIOption.OnlyErrorDialogs, FileIO.RecycleOption.DeletePermanently, FileIO.UICancelOption.DoNothing)
            Catch ex As Exception
                MsgBox(ex.Message)
            End Try
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
        exit_excel_process.Show()
    End Sub

除非我将 MsgBox 代码放入其中，否则不会将任何数据保存到 Excel 文件中。

Answer 1

由于 Try 不起作用，因此焦点被踢到了 Catch 上。这样做似乎过于复杂。请参阅下面的代码示例。你能解决这个问题吗？

Imports System.Data
Imports System.Data.SqlClient
Imports Excel = Microsoft.Office.Interop.Excel
Public Class Form1
    Private Sub Button1_Click(ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles Button1.Click

        Dim cnn As SqlConnection
        Dim connectionString As String
        Dim sql As String

        connectionString = "data source=servername;" & _
        "initial catalog=databasename;user id=username;password=password;"
        cnn = New SqlConnection(connectionString)
        cnn.Open()
        sql = "SELECT * FROM Product"
        Dim dscmd As New SqlDataAdapter(sql, cnn)
        Dim ds As New DataSet
        dscmd.Fill(ds)
        DataGridView1.DataSource = ds.Tables(0)
        cnn.Close()
    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, _
    ByVal e As System.EventArgs) Handles Button2.Click


        Dim xlApp As Excel.Application
        Dim xlWorkBook As Excel.Workbook
        Dim xlWorkSheet As Excel.Worksheet
        Dim misValue As Object = System.Reflection.Missing.Value
        Dim i As Integer
        Dim j As Integer

        xlApp = New Excel.ApplicationClass
        xlWorkBook = xlApp.Workbooks.Add(misValue)
        xlWorkSheet = xlWorkBook.Sheets("sheet1")

        For i = 0 To DataGridView1.RowCount - 2
            For j = 0 To DataGridView1.ColumnCount - 1
                xlWorkSheet.Cells(i + 1, j + 1) = _
                    DataGridView1(j, i).Value.ToString()
            Next
        Next

        xlWorkSheet.SaveAs("C:\vbexcel.xlsx")
        xlWorkBook.Close()
        xlApp.Quit()

        releaseObject(xlApp)
        releaseObject(xlWorkBook)
        releaseObject(xlWorkSheet)

        MsgBox("You can find the file C:\vbexcel.xlsx")
    End Sub

    Private Sub releaseObject(ByVal obj As Object)
        Try
            System.Runtime.InteropServices.Marshal.ReleaseComObject(obj)
            obj = Nothing
        Catch ex As Exception
            obj = Nothing
        Finally
            GC.Collect()
        End Try
    End Sub
End Class