Question

我有一个访问数据库，其中包含一个需要整数的字段。我传递了一些从Excel电子表格中检索到的数据，如果从单元格中检索到字符串，则调用函数的Try / Catch将触发FormatException。我想弄清楚的是，是否可能（并且始终是）抛出一个自定义错误消息，该消息将显示包含无效数据的单元格地址。这是我的一些示例代码。

Public Class Main
Private cellAddress As String
Private Sub btn_Import(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnImport.Click
    Dim openFileDialog As New OpenFileDialog()
    openFileDialog.InitialDirectory = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments)
    openFileDialog.Filter = "Excel Files (*.xls)|*.xlsx|All files (*.*)|*.*"
    openFileDialog.RestoreDirectory = True
    If openFileDialog.ShowDialog() <> Windows.Forms.DialogResult.OK Then
        Return
    End If
    Try
        ImportWorksheet(New FileInfo(openFileDialog.FileName))
    Catch ex As FormatException
        MessageBox.Show("The data contained within cell " & cellAddress &  " is invalid.", "Error")
    End Try
End Sub

Private Sub ImportWorksheet(ByVal excelFile As FileInfo)
    Dim cnn As New OleDbConnection(My.Settings.cnn)
    Dim cmd As OleDbCommand = GetCommand("UpdateSite")
    Dim worksheet1 As ExcelWorksheet = package.Workbook.Worksheets(1)
    Using package As New ExcelPackage(excelFile)
        Using cmd.Connection
            cmd.Connection.Open()
            cmd.Parameters.Add("@MyData", OleDbType.Integer).Value = GetCellContents(worksheet1, "K8")
            cmd.ExecuteNonQuery()
        End Using
End Sub

Private Function GetCellContents(ByVal worksheet As ExcelWorksheet, ByVal address As String) As Object
    If worksheet.Cells(address).Value Is Nothing Then
        Return DBNull.Value
    Else
        cellAddress = address
        Return worksheet.Cells(address).Value
    End If
End Function
End Class

不要以为我在这里遗漏任何东西，我有点复制和粘贴并修改代码以缩短并且不放弃任何不需要的信息。一旦代码命中ExecuteNonQuery（）方法，错误就会冒泡并说出我写的任何内容。如果发生这种情况，我想传递单元格地址，以便他们知道在哪里查看。

我能想到这样做的唯一方法是添加一个类级变量，并在每次获取值时将其设置为当前单元格。唯一的问题是，因为它只在ExecuteNonQuery（）触发，并且我有多个参数，如果第一个添加的参数无效但下一个参数不是，那么每次都将单元格设置为最后一个参数，我得到了错误的结果。有没有办法从数据库中获取某种消息，告诉我具体哪个参数没有正确转换？

Answer 1

没关系，我现在就跟它一起去了......这很有效，但如果你们能给我一些更好的东西，请做。

cmd.Parameters.Add("@MyData", OleDbType.Integer).Value = GetCellContents(worksheet2, "K8", "Int32")

 Private Function GetCellContents(ByVal worksheet As ExcelWorksheet, ByVal address As String, Optional ByVal type As String = Nothing) As Object
    If worksheet.Cells(address).Value Is Nothing Then
        Return DBNull.Value
    Else
        cellAddress = address
        Select Case type
            Case Is = "String"
                Return Convert.ToString(worksheet.Cells(address).Value)
            Case Is = "Int32"
                Return Convert.ToInt32(worksheet.Cells(address).Value)
            Case Is = "DateTime"
                Return Convert.ToDateTime(worksheet.Cells(address).Value)
            Case Else
                Return worksheet.Cells(address).Value
        End Select
    End If
End Function

捕获访问数据库错误（FormatException）并返回自定义消息？

1 个答案: