VB.NET在datagridview的Access數據庫中保存delete命令

Question

我有使用SQL命令從數據庫中刪除選擇行的工作代碼，並且如果我在訪問中使用它，該命令也會起作用。 但是，當我要使用VB.NET中的delete按鈕執行此操作時，它不會保存它。 當我檢查程序是否消失時，它可以工作並更新所有內容，依此類推。 當我退出程序並再次啟動它時，它又恢復了正常。 我急需修復方面的幫助！

Imports System.Data.OleDb

Public Class CustomersForm
    Dim Contact(-1) As CustomerData
    ''' <summary>
    ''' Load Form and Fill Table Adapter
    ''' </summary>
    ''' <param name="sender"></param>
    ''' <param name="e"></param>
    ''' <remarks></remarks>
    Private Sub CustomersForm_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        'TODO: This line of code loads data into the 'MooselyAdventuresDataSet.tblCustomers' table. You can move, or remove it, as needed.
        Me.TblCustomersTableAdapter.Fill(Me.MooselyAdventuresDataSet.tblCustomers)
        LoadCustomerInformation()
    End Sub
    ''' <summary>
    ''' Structure for data for datagrid view and to hold data for cells
    ''' </summary>
    ''' <remarks></remarks>
    Structure CustomerData
        Public LongCustomerID As Long
        Public FirstName As String
        Public LastName As String
        Public Address As String
        Public City As String
        Public State As String
        Public Zip As Integer
        Public Email As String
    End Structure
    ''' <summary>
    ''' Close Customers Form
    ''' </summary>
    ''' <param name="sender"></param>
    ''' <param name="e"></param>
    ''' <remarks></remarks>
    Private Sub btCustClose_Click(sender As Object, e As EventArgs) Handles btCustClose.Click
        Me.Close()
    End Sub
    ''' <summary>
    ''' Call the Sql statement and retrieve data and fill the datagridview control
    ''' </summary>
    ''' <remarks></remarks>
    Private Sub LoadCustomerInformation()
        dgvCustomers.Rows.Clear()
        dgvCustomers.Columns.Clear()
        Dim CustData As New CustomerInfoGetter

        'Set customer string to the module
        CustData.ConnectionString = mdlConnectString.ConnectionString
        CustData.Sql = "SELECT CustomerLast, CustomerFirst, CustomerAddress, CustomerCity, CustomerState, CustomerZip, CustomerEmail, CustomerID FROM tblCustomers"
        'Add Columns for datagrid view
        dgvCustomers.Columns.Add("First Name", "First Name")
        dgvCustomers.Columns.Add("Last Name", "Last Name")
        dgvCustomers.Columns.Add("Street Address", "Street Address")
        dgvCustomers.Columns.Add("City", "City")
        dgvCustomers.Columns.Add("State", "State")
        dgvCustomers.Columns.Add("Zip", "Zip")
        dgvCustomers.Columns.Add("Email", "Email")
        dgvCustomers.Columns.Add("CustomerID", "CustomerID")



        For I As Integer = 0 To CustData.DS.Tables(0).Rows.Count - 1
            ReDim Preserve Contact(Contact.Length)
            With Contact(Contact.Length - 1) 'loop to add data to datagridview and getting data from sql statement'
                .FirstName = CustData.DS.Tables(0).Rows(I).Item("CustomerFirst").ToString()
                .LastName = CustData.DS.Tables(0).Rows(I).Item("CustomerLast").ToString()
                .Address = CustData.DS.Tables(0).Rows(I).Item("CustomerAddress").ToString()
                .City = CustData.DS.Tables(0).Rows(I).Item("CustomerCity").ToString()
                .State = CustData.DS.Tables(0).Rows(I).Item("CustomerState").ToString()
                .Zip = CustData.DS.Tables(0).Rows(I).Item("CustomerZip").ToString()
                .Email = CustData.DS.Tables(0).Rows(I).Item("CustomerEmail").ToString()
                .LongCustomerID = CustData.DS.Tables(0).Rows(I).Item("CustomerID").ToString()
                dgvCustomers.Rows.Add() 'add a row to fill information'
                dgvCustomers.Rows(I).Cells(0).Value = .FirstName
                dgvCustomers.Rows(I).Cells(1).Value = .LastName
                dgvCustomers.Rows(I).Cells(2).Value = .Address
                dgvCustomers.Rows(I).Cells(3).Value = .City
                dgvCustomers.Rows(I).Cells(4).Value = .State
                dgvCustomers.Rows(I).Cells(5).Value = .Zip
                dgvCustomers.Rows(I).Cells(6).Value = .Email
                dgvCustomers.Rows(I).Cells(7).Value = .LongCustomerID


            End With
        Next

        dgvCustomers.Columns(7).Visible = False 'Make Last Row Invisible'
    End Sub
    ''' <summary>
    ''' When a cell is clicked (Actually entire rows are only selected....) it will changed the textboxes and combo box to according
    ''' values
    ''' </summary>
    ''' <param name="sender"></param>
    ''' <param name="e"></param>
    ''' <remarks></remarks>
    Private Sub dgvCustomers_CellClick(sender As Object, e As DataGridViewCellEventArgs) Handles dgvCustomers.CellClick
        Dim i As Integer = dgvCustomers.CurrentRow.Index

        'Fill Text Boxes and Such When Clicked'
        tbLastName.Text = dgvCustomers.Rows(i).Cells(1).Value
        tbFirstName.Text = dgvCustomers.Rows(i).Cells(0).Value
        tbStreet.Text = dgvCustomers.Rows(i).Cells(2).Value
        tbCity.Text = dgvCustomers.Rows(i).Cells(3).Value
        cbStates.Text = dgvCustomers.Rows(i).Cells(4).Value
        tbZipCode.Text = dgvCustomers.Rows(i).Cells(5).Value
        tbEmail.Text = dgvCustomers.Rows(i).Cells(6).Value

    End Sub

    Private Sub btDelete_Click(sender As Object, e As EventArgs) Handles btDelete.Click

        Try
            Dim CustData As New CustomerInfoGetter
            Dim CustIDDelete As String


            CustIDDelete = dgvCustomers.Rows(dgvCustomers.CurrentRow.Index).Cells(7).Value

            'Set customer string to the module
            CustData.ConnectionString = mdlConnectString.ConnectionString
            CustData.Sql = "DELETE FROM tblCustomers WHERE CustomerID = " & CustIDDelete
            LoadCustomerInformation()


        Catch
            MessageBox.Show("You Can't Delete When Their Are No Records !", "Error !")
        End Try

    End Sub

    Private Sub btAdd_Click(sender As Object, e As EventArgs) Handles btAdd.Click

    End Sub
End Class

Answer 1

我不確定您在代碼中到底在做什么，但是我寫了一個小函數來做您想要的

Public Shared Function CreateCustomerAdapter( _
    connection As OleDbConnection) As OleDbDataAdapter 

    Dim dataAdapter As OleDbDataAdapter = New OleDbDataAdapter()
    Dim command As OleDbCommand
    Dim parameter As OleDbParameter

    ' Your DELETE command.
    command = New OleDbCommand( _
        "DELETE * FROM tblCustomers WHERE CustomerID = ?", _
        connection)

    parameter = command.Parameters.Add( _
        "CustomerID", OleDbType.Char, 5, "CustomerIDDelete")

    parameter.SourceVersion = DataRowVersion.Original

    dataAdapter.DeleteCommand = command

    Return dataAdapter
End Function

接着

command.ExecuteNonQuery()

最后但並非最不重要的一點，請記住在SQL語句上使用參數化，因為它會遵循良好的做法並防止出現SQL注入之類的安全性問題。 那就是OleDbParameter目的。 檢查下面的MSDN頁面以獲取更多信息

OleDbCommand.Parameters屬性