我正在为调用构建一个投票系统,并试图在VB中构建它。到目前为止,这是我的:VB应用程序中的NullReferenceException错误?
Dim con As New OleDb.OleDbConnection
Dim dbProvider As String
Dim dbSource As String
dbProvider = "PROVIDER=Microsoft.Jet.OLEDB.4.0;"
dbSource = "Data Source = C:\PhonePoll.mdb"
con.ConnectionString = dbProvider & dbSource
con.ConnectionString = "PROVIDER=Microsoft.Jet.OLEDB.4.0;Data Source = C:\PhonePoll.mdb"
con.Open()
'sql = "SELECT * FROM voting"
'da = New OleDb.OleDbDataAdapter(sql, con)
'da.Fill(ds, "voting")
If inc <> -1 Then
Dim cb As New OleDb.OleDbCommandBuilder(da)
Dim dsNewRow As DataRow
dsNewRow = ds.Tables("voting").NewRow()
dsNewRow.Item("voted") = RadioButton1.Checked.ToString
dsNewRow.Item("voted") = RadioButton2.Checked.ToString
dsNewRow.Item("voted") = RadioButton3.Checked.ToString
dsNewRow.Item("voted") = RadioButton4.Checked.ToString
ds.Tables("voting").Rows.Add(dsNewRow)
da.Update(ds, "voting")
MsgBox("New Record added to the Database")
End If
MsgBox("Phone call has been logged")
con.Close()
此代码包含在“记录呼叫”按钮。在表格上,有四个单选按钮,全部都有不同的文本值,应该输入到“投票”表中。
我的问题是,当我选择一个单选按钮,然后单击“录音键”,它则显示此错误:
NullReferenceException: Object reference not set to an instance of an object.
显示上线
dsNewRow = ds.Tables("voting").NewRow()
我”这个错误我不知道我做错了什么。
欢呼声!
我不明白,我评论他们出来,因为它没有摆在首位的工作。我现在取消注释他们,它的作品?谢谢您的帮助! – mickburkejnr 2011-04-11 22:30:39