在後臺工作人員之間傳遞Excel變量

Question

我有兩個後臺工作人員，需要將事務從第一個傳遞給另一個工作人員。

這就是我試圖通過：

Dim APP As Excel.Application = New Microsoft.Office.Interop.Excel.Application() 
Dim workbook As Excel.Workbook 
Dim worksheet As Excel.Worksheet 
Dim worksheetRange As Excel.Range 
Dim status As String 

這是如何，我想通過它：

Private Sub bwExport_DoWork(sender As Object, e As DoWorkEventArgs) Handles bwExport.DoWork 
    Dim APP As Excel.Application = New Microsoft.Office.Interop.Excel.Application() 
    Dim workbook As Excel.Workbook 
    Dim worksheet As Excel.Worksheet 
    Dim worksheetRange As Excel.Range 
    Dim status As String 

    'code stuff here 

    Dim ExportList As New List(Of Object)(5) 
    ExportList.Add(APP) 
    ExportList.Add(workbook) 
    ExportList.Add(worksheet) 
    ExportList.Add(worksheetRange) 
    ExportList.Add(status) 
    e.Result = ExportList 
End Sub 


Private Sub bwExport_RunWorkerCompleted(sender As Object, e As RunWorkerCompletedEventArgs) Handles bwExport.RunWorkerCompleted 
     bwExportFinish.RunWorkerAsync(e.Result) 
End Sub 

而這就是我試圖找回它的方式：

Private Sub bwExportFinish_DoWork(sender As Object, e As DoWorkEventArgs) Handles bwExportFinish.DoWork 
    Dim ExportList As List(Of Object) = TryCast(e.Result, List(Of Object)) 
    Dim APP As Excel.Application = TryCast(ExportList(0), Excel.Application) 
    Dim workbook As Excel.Workbook = TryCast(ExportList(1), Excel.Workbook) 
    Dim worksheet As Excel.Worksheet = TryCast(ExportList(2), Excel.Worksheet) 
    Dim worksheetRange As String = TryCast(ExportList(3), String) 
    Dim status As String = TryCast(ExportList(4), String) 

    'Save spreadsheet 
    Dim SavePath = Environment.GetFolderPath(Environment.SpecialFolder.Desktop) & "\" & label1.Text & " " & Status & " Status " & System.DateTime.Now.ToString("MM.dd.yyyy HH;mm;ss") & ".xlsx" 
    workbook.SaveAs(SavePath) 
    workbook.Close(False) 
End Sub 

這是我發現了錯誤：
1.線：昏暗APP作爲Excel.Application = TryCast（ExportList（0），Excel.Application（ ））
給我錯誤：'Application（）'類型的值不能被轉換爲'Application'。
我是盲人。我剛剛發生格式錯誤。這是固定的。

2.我得到的是，在VS2015帶來了一個網頁的錯誤，上面寫着「電源不可用」，然後類型「System.Reflection.TargetInvocationException」未處理的異常出現在mscorlib.dll



有沒有人有任何想法？

Answer 1

好吧，在你的代碼中有幾個錯誤，我要指出它們。

• 正如我在評論中提及上面：

  The error actually explains it pretty well. Your original variable is of type Excel.Application, while Excel.Application() is an array of the same type. Hence, you would need to cast it as Excel.Application if casting is even required.

• 在你的第二個BackgroundWorker的（bwExportFinish），你試圖讓你從第一的BackgroundWorker通過List(Of Object)，但你使用錯誤的變量（e.Result）。怎麼樣？那麼，你存儲在e.Result的第一個 BackgroundWorker不是第二個之一。現在將該列表傳遞給第二個BackgroundWorker之後，您可以使用e.Argument而不是e.Result來訪問它。

• 另一個小錯誤是，您創建了Excel.Range類型的變量worksheetRange，然後將其轉換爲String。

因此，你在第二BackgroundWorker的代碼看起來應該像下面這樣：

Private Sub bwExportFinish_DoWork(sender As Object, e As DoWorkEventArgs) Handles bwExportFinish.DoWork 
    Dim ExportList As List(Of Object) = TryCast(e.Argument, List(Of Object)) 
    If ExportList Is Nothing Then 
     ' Casting has failed. Choose how you want to handle this. 
    End If 

    'Dim APP As Excel.Application = TryCast(ExportList(0), Excel.Application) 
    'Or you can skip the casting if you already know you passed the right object. 
    Dim APP As Excel.Application = ExportList(0) 
    Dim workbook As Excel.Workbook = ExportList(1) 
    Dim worksheet As Excel.Worksheet = ExportList(2) 
    Dim worksheetRange As Excel.Range = ExportList(3) 
    Dim status As String = ExportList(4) 

    'Save spreadsheet 
    workbook.SaveAs(SavePath) 
    workbook.Close(False) 
    APP.Quit() 
End Sub 

希望幫助:)