Vb.net 尝试写入已存在的Excel文件时出现NullReferenceException
我正试图写入现有Excel文件,但出现Vb.net 尝试写入已存在的Excel文件时出现NullReferenceException,vb.net,nullreferenceexception,excel-interop,Vb.net,Nullreferenceexception,Excel Interop,我正试图写入现有Excel文件,但出现NullReferenceException错误。我该怎么做才能修好它 我正在引用Microsoft Excel 16.0对象库 以下是我所做的: Imports Excel = Microsoft.Office.Interop.Excel Public Class manager Dim oExcel As Excel.Application Dim oBook As Excel.Workbook Dim oSheet As Exc
NullReferenceException
错误。我该怎么做才能修好它
我正在引用Microsoft Excel 16.0对象库
以下是我所做的:
Imports Excel = Microsoft.Office.Interop.Excel
Public Class manager
Dim oExcel As Excel.Application
Dim oBook As Excel.Workbook
Dim oSheet As Excel.Worksheet
Dim oRange As Excel.Range
Dim box1 As Integer = 0
Dim i As Integer = 2
Private Sub CheckBox1_CheckedChanged(sender As Object, e As EventArgs) Handles CheckBox1.CheckedChanged
box1 = 1
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Try
oBook = oExcel.Workbooks.Open("C:\puthere.xlsx")
Catch ex As NullReferenceException
End Try
Try
oSheet = oBook.Worksheets("sheet1")
Catch ex As NullReferenceException
End Try
Try
oSheet.Range("B" & i).Value = box1
Catch ex As NullReferenceException
End Try
End Sub
End Class
我尝试使用Try Catch
并成功地停止了错误。但是这个程序不起作用。没有错误,但文件中没有更改。当我将路径和文件名更改为不存在时,程序也会执行相同的操作(没有错误,只是没有写入任何内容)
我尝试使用Try Catch
并成功地停止了错误。但是这个程序不起作用。没有错误,但文件中没有更改
这是因为a不能停止错误。请查看MSDN文档:
提供一种方法来处理给定代码块中可能出现的部分或所有错误,同时仍在运行代码
现在谈谈手头的问题。出现NullReferenceException
错误的原因是您尚未创建oExcel
的新实例:
Dim oExcel As New Excel.Application