在 vb.net 中关闭应用程序后访问数据库数据未保存

Question

问题 我有一个连接到我的程序的数据库，我知道它连接正确，因为我可以通过其他两种形式访问该数据库。在一种形式中，我将输入的登录详细信息与数据库进行比较，它工作正常，另一种形式的奇怪之处在于，我使用更新语句将新用户添加到表中，并且这些数据在关闭并重新启动应用程序后仍然存在。为了澄清问题是在编辑 dataveiw 中的数据并且单击保存按钮显示为已保存时，此表单上的问题，但是当程序关闭并打开时，此数据不存在。

守则

Imports System.Data
Imports System.Data.OleDb
Imports System.Data.Odbc
Imports System.Data.DataTable

Public Class FrmFinance

Dim provider As String
Dim dataFile As String
Dim connString As String
Dim myConnection As OleDbConnection = New OleDbConnection
Dim ds As DataSet = New DataSet
Dim da As OleDbDataAdapter
Dim tables As DataTableCollection = ds.Tables
Dim varsearch As New BindingSource()
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    'TODO: This line of code loads data into the 'MasterDBDataSet.Table_usr' table. You can move, or remove it, as needed.
    Me.Table_usrTableAdapter.Fill(Me.MasterDBDataSet.Table_usr)

    connString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\Users\Student\Documents\Visual Studio 2010\Projects\MasterDB.accdb"
    myConnection.ConnectionString = connString
    da = New OleDbDataAdapter("Select [Username], [Surname], [YearGroup] from Table_usr", myConnection)
    da.Fill(ds, "Table_usr")
    Dim searchveiw As New DataView(tables(0))
    varsearch.DataSource = searchveiw
    DataGridView1.DataSource = searchveiw
    DataGridView1.Refresh()
End Sub
Private Sub ButtSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ButtSave.Click
    Try
        TableusrBindingSource.EndEdit()
        Table_usrTableAdapter.Update(MasterDBDataSet.Table_usr)
        MessageBox.Show("Data Saved")
    Catch ex As Exception
        MessageBox.Show("Error Saving Data")
    End Try
End Sub

Private Sub ButtFilter_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ButtFilter.Click
    If Search_username.TextLength > 1 Then
        varsearch.Filter = "[Username] = '" & Search_username.Text & "'"
        DataGridView1.Refresh()
    ElseIf Search_Surname.TextLength > 1 Then
        varsearch.Filter = "[Surname] = '" & Search_Surname.Text & "'"
        DataGridView1.Refresh()
    ElseIf Search_YrGroup.TextLength > 1 Then
        varsearch.Filter = "[YearGroup] = '" & Search_YrGroup.Text & "'"
        DataGridView1.Refresh()
    End If
End Sub
End Class

我包含了整个表格，以防出现我不理解的冲突。当我设置数据源时，我单击“否”以在每次运行时将数据库复制到 bin 中，并且 database.xcd 设置为如果更新但信息在关闭时仍然丢失则复制。非常感谢任何帮助。

Answer 1

试试这个，

Private Sub Form1_Closing(sender As Object, e As CancelEventArgs) Handles Me.Closing
    Try
        Me.Validate()
        TableusrBindingSource.EndEdit()
        Table_usrTableAdapter.UpdateAll(Me.MasterDBDataSet.Table_usr)
        MessageBox.Show("Data Saved")
    Catch ex As Exception
        MessageBox.Show("Error Saving Data")
    End Try
End Sub