为什么我必须在这里转换'Cells'？

Question

小问题：我注意到我必须在此处使用 CType 进行转换，即使 Cells 已经返回 Range。我究竟做错了什么？ Cells 是只读的，不接受任何参数。好吧，我曾经被这样展示过。

如果我这样做

xlRange = myWorksheet.Cells(Line + 1US, 2US)

错误是

Option Strict On disallows implicit conversions from 'Object' to 'Range'

我想提一提——如果是因为这个原因的话——我关闭了 Option Infer Off，这样我就可以强迫自己始终写下类型。

源代码应该在Excelsheet中写入一段时间的测量值。

示例：

    A          B        C
1  07.09.2021  08:00    25,0
2              12:00    30,0
3              16:00    35,0
4  08.09.2021  08:00    26,0
5              12:00    28,0
6              16:00    26,0

class-范围变量：

Private Time_of_the_program_start As Date
Private Duration_of_the_runtime As TimeSpan
Private xlApp As Excel.Application
Private myWorkbook As Excel.Workbook
Private running As Boolean = False
Private Line As UInt16 = 0US
Private ReadOnly Deu As New System.Globalization.CultureInfo("de-DE")

running 在按钮过程中设置为 True。

Private Function read_and_write_data(ByVal file_path As String) As Boolean
        xlApp = New Excel.Application With {
            .Visible = True
        }
        myWorkbook = xlApp.Workbooks.Add()
        Dim myWorksheet As Excel.Worksheet = CType(myWorkbook.Sheets("Tabelle1"), Excel.Worksheet)
        Dim xlRange As Excel.Range
        Dim Temperatur As Single

        While running
            Duration_of_the_runtime = Date.Now - Time_of_the_program_start
            If Duration_of_the_runtime.Days = 365 Then Exit While

            Me.Invoke(Sub() Label_Duration.Text =
                          Duration_of_the_runtime.Days.ToString(Deu).PadLeft(3, "0"c) & ":" &
                          Duration_of_the_runtime.Hours.ToString(Deu).PadLeft(2, "0"c) & ":" &
                          Duration_of_the_runtime.Minutes.ToString(Deu).PadLeft(2, "0"c))

            'System.Threading.Thread.Sleep(10000)
            'myWorksheet.Cells(Line, column)
            '–––––––––––––––––––––––––––––––––––––––
            'Spalte A: Datum
            '–––––––––––––––––––––––––––––––––––––––
            xlRange = CType(myWorksheet.Cells(Line + 1US, 1US), Excel.Range)
            xlRange.Value = Date.Now.ToString("d", Deu)
            '–––––––––––––––––––––––––––––––––––––––
            'Spalte B: Uhrzeiten
            'Spalte C: Messwerte
            '–––––––––––––––––––––––––––––––––––––––
            Temperatur = Get_Temperature_from_Pt100()

            xlRange = CType(myWorksheet.Cells(Line + 1US, 2US), Excel.Range)
            xlRange.Value = Date.Now.ToString("t", Deu)

            xlRange = CType(myWorksheet.Cells(Line + 1US, 3US), Excel.Range)
            xlRange.Value = Temperatur
            '‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐
            Temperatur = Get_Temperature_from_Pt100()
            xlRange = CType(myWorksheet.Cells(Line + 2US, 2US), Excel.Range)
            xlRange.Value = Date.Now.ToString("t", Deu)

            xlRange = CType(myWorksheet.Cells(Line + 2US, 3US), Excel.Range)
            xlRange.Value = Temperatur
            '‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐
            Temperatur = Get_Temperature_from_Pt100()
            xlRange = CType(myWorksheet.Cells(Line + 3US, 2US), Excel.Range)
            xlRange.Value = Date.Now.ToString("t", Deu)

            xlRange = CType(myWorksheet.Cells(Line + 3US, 3US), Excel.Range)
            xlRange.Value = Temperatur
            '–––––––––––––––––––––––––––––––––––––––
            'inkrementieren
            '–––––––––––––––––––––––––––––––––––––––
            Line += 3US
        End While

        myWorksheet.SaveAs(file_path, Excel.XlFileFormat.xlWorkbookDefault)
        myWorkbook.Close()
        xlApp.Quit()
        If myWorksheet IsNot Nothing Then System.Runtime.InteropServices.Marshal.ReleaseComObject(myWorksheet)
        If myWorkbook IsNot Nothing Then System.Runtime.InteropServices.Marshal.ReleaseComObject(myWorkbook)
        If xlApp IsNot Nothing Then System.Runtime.InteropServices.Marshal.ReleaseComObject(xlApp)
        xlApp = Nothing
        myWorkbook = Nothing
        myWorksheet = Nothing

        Return True
    End Function

顺便说一句：有没有更优雅的解决方案？

Me.Invoke(Sub() Label_Duration.Text =
                          Duration_of_the_runtime.Days.ToString(Deu).PadLeft(3, "0"c) & ":" &
                          Duration_of_the_runtime.Hours.ToString(Deu).PadLeft(2, "0"c) & ":" &
                          Duration_of_the_runtime.Minutes.ToString(Deu).PadLeft(2, "0"c))

Answer 1

对于您的主要问题，不，您没有做错任何事情，这正是 Excel 自动化界面的行为方式。具体来说，集合类型都是经典的 VBA Collection（或等效的功能），这意味着索引访问 returns 和 Object 而不是强类型的东西。

正如您所指出的，如果您尝试在 Option Strict On 上下文中使用它，则必须强制转换结果。我自己的互操作代码有一堆收集项访问，到处都是 DirectCast(.Rows(2), Excel.Range)...

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为什么我必须在这里转换'Cells'？

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