在后台工作人员之间传递Excel变量

Question

我有两个后台工作人员，需要将事务从第一个传递给另一个工作人员。

这就是我试图通过：

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 

这是如何，我想通过它：

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 

而这就是我试图找回它的方式：

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 

这是我发现了错误：
1.线：昏暗APP作为Excel.Application = TryCast（ExportList（0），Excel.Application（ ））
给我错误：'Application（）'类型的值不能被转换为'Application'。
我是盲人。我刚刚发生格式错误。这是固定的。

2.我得到的是，在VS2015带来了一个网页的错误，上面写着“电源不可用”，然后类型“System.Reflection.TargetInvocationException”未处理的异常出现在mscorlib.dll



有没有人有任何想法？

Answer 1

好吧，在你的代码中有几个错误，我要指出它们。

• 正如我在评论中提及上面：

  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.

• 在你的第二个BackgroundWorker的（bwExportFinish），你试图让你从第一的BackgroundWorker通过List(Of Object)，但你使用错误的变量（e.Result）。怎么样？那么，你存储在e.Result的第一个 BackgroundWorker不是第二个之一。现在将该列表传递给第二个BackgroundWorker之后，您可以使用e.Argument而不是e.Result来访问它。

• 另一个小错误是，您创建了Excel.Range类型的变量worksheetRange，然后将其转换为String。

因此，你在第二BackgroundWorker的代码看起来应该像下面这样：

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 

希望帮助:)