OLEDB连接未处理错误

Question

我正在尝试将一些数据库记录链接到文本框和带有visual basic和OLEDB的列表框但是当我调试程序时，即使数据库位于bin/debug文件夹中，程序也无法识别它。

以下是代码：

Imports System.Data.OleDb
Public Class Form1

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Dim ConnectString As String = "Provider = Microsoft.Jet.OLEDB.4.0;" & _
        "Data Source = Hospital.mdb"
        Dim dtPatientsIDs As New DataTable
        Dim daPatientIDs As New OleDbDataAdapter _
        ("Select [Patient ID] From Patients", ConnectString)

        daPatientIDs.Fill(dtPatientsIDs)
        lstPatientIDs.DataSource = dtPatientsIDs
        lstPatientIDs.DisplayMember = "Patient ID"

        OleDbDataAdapter1.Fill(DsPatientsAndWards1)
        txtWardName.DataBindings.Add("Text", DsPatientsAndWards1, _
                                 "Patients.Ward Name")
        txtWardType.DataBindings.Add("Text", DsPatientsAndWards1, _
                                 "Patients.Ward Type")



    End Sub

    Private Sub btnPrevious_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnPrevious.Click
        BindingContext(DsPatientsAndWards1, "Patients").Position = _
        BindingContext(DsPatientsAndWards1, "Patients").Position - 1

    End Sub

    Private Sub btnNext_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnNext.Click
        BindingContext(DsPatientsAndWards1, "Patients").Position = _
        BindingContext(DsPatientsAndWards1, "Patients").Position + 1
    End Sub

    Private Sub btnFind_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnFind.Click
        Dim index As Short
        index = lstPatientIDs.SelectedIndex
        BindingContext(DsPatientsAndWards1, "Patients").Position = index

    End Sub
End Class

here is the error and its location

Answer 1

尝试更改

Dim daPatientIDs As New OleDbDataAdapter _
    ("Select [Patient ID] From Patients", ConnectString)

到

Dim Con as NEW OleDBConnection(ConnectionString)
Dim daPatientIDs As New OleDbDataAdapter _
    ("Select [Patient ID] From Patients", Con)

并添加

Con.open()

之前

    OleDbDataAdapter1.Fill(DsPatientsAndWards1)