vb.net即使在投射后也不会消失对象的实例

Question

我有以下代码遍历Excel文件，这很好用

请注意，以下行确实有效（代码中的文件夹正在设置中）

Console.WriteLine("Value found in {1}: {0} ", Obj.Text, folder)

整个

For Each xlWorkSheet In xlWorkBook.Worksheets
    For rCnt As Integer = 2 To xlWorkSheet.UsedRange.Rows.Count 'we start at 2 becuase we do not need the first header row

        For cCnt As Integer = 1 To xlWorkSheet.UsedRange.Columns.Count

            Dim Obj As Range = CType(xlWorkSheet.UsedRange.Cells(rCnt, cCnt), Range)

            Console.WriteLine("Value found in {1}: {0} ", Obj.Text, folder)

        Next


        RaiseEvent ImportChanged()
    Next

Next

但我想填写一个包含这些项目的字典，但是当我这样做时，它抱怨它“不是一个对象的实例”，即使我将它转换为Cstr（）或使用.toString

任何人都知道为什么？

Dim EntryDetails As Dictionary(Of String, String)

        For Each xlWorkSheet In xlWorkBook.Worksheets
            For rCnt As Integer = 2 To xlWorkSheet.UsedRange.Rows.Count 'we start at 2 becuase we do not need the first header row

                For cCnt As Integer = 1 To xlWorkSheet.UsedRange.Columns.Count

                    Dim Obj As Range = CType(xlWorkSheet.UsedRange.Cells(rCnt, cCnt), Range)

                    Console.WriteLine("Value found in {1}: {0} ", Obj.Text, folder)
                    EntryDetails.Add("demo", Obj.Text) ' THIS DOESNT WORK
                    EntryDetails.Add("demo", Obj.Text.ToString) ' THIS DOESNT WORK
                    EntryDetails.Add("demo", CStr(Obj.Text)) ' THIS DOESNT WORK

                Next


                RaiseEvent ImportChanged()
            Next

        Next

Answer 1

您尚未创建EntryDetails

的实际实例

将New关键字添加到第一行，以便调用构造函数：

Dim EntryDetails As New Dictionary(Of String, String)

For Each xlWorkSheet In xlWorkBook.Worksheets
    // ...
Next