VB.NET错误：“ConnectionString属性尚未初始化。”

Dim Current As String 
Current = Directory.GetCurrentDirectory() 
con.ConnectionString = "PROVIDER = Microsoft.Jet.OLEDB.4.0;Data Source = " & Current & "\SchoolMaticsDatabase.mdb" 
con.Open() 
TabSelect() 
con.Close() 

Private Sub TabSelect() 
     Select Case TabControl1.SelectedIndex 
      Case Is = 0 
       TabDay = "Monday" 
      Case Is = 1 
       TabDay = "Tuesday" 
      Case Is = 2 
       TabDay = "Wednesday" 
      Case Is = 3 
       TabDay = "Thursday" 
      Case Is = 4 
       TabDay = "Friday" 
      Case Is = 5 
       TabDay = "Saturday" 
      Case Is = 6 
       TabDay = "Sunday" 
     End Select 
     ds.Clear() 
     sql = "SELECT [Forename],[Surname],[Subject Speciality 1],[Subject Speciality 2],[Subject Speciality 3],[Subject Speciality 4],[Subject Speciality 5],[Subject Speciality 6]," & StartTime & "," & EndTime & ",[Spec1],[Spec2],[Spec3],[Spec4],[Spec5],[Spec6] FROM [Staff] WHERE " & TabDay & " LIKE 'T'" 
     da = New OleDb.OleDbDataAdapter(sql, con) 
     da.Fill(ds, "SchoolMaticsDatabase") 
End Sub

da.fill（ds，“SchoolMaticsDatabase”）>>>错误发生在这行代码中。VB.NET错误：“ConnectionString属性尚未初始化。”

如果选项卡索引被改变，子选项卡选择（）也被调用。还有一件事是程序检查星期几并正确显示与当天相对应的标签。星期一这段代码工作正常，只要星期二发布了这个错误就会出现。

来源

2011-08-23 LionSword

代码片段无法编译为给定。改进它并显示前6行出现的内部方法。并展示你如何称此方法。 –

需要更多信息来发布适当的答案 –

尝试将conn作为参数传递给TabSelect（）函数。 TabSelect(ByRef OleDbConnection conn)这可能是一个范围问题，因为你正在玩全局变量

来源

2011-08-23 01:55:33

感谢您的信息。我尝试通过函数传递连接变量，但同样的错误正在发生。 – LionSword

'conn'初始化在哪里？ –

VB.NET错误：“ConnectionString属性尚未初始化。”

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