Question

我正在使用带有DataGridView的VB.NET 2008，并且我使用vfpoledb.1驱动程序连接到Visual Foxpro 6数据库。当我更改说明字段中的值时，它会在DataGridView中更改，但数据库永远不会更新。我是否需要使用代码来强制进行更改？

这是我正在使用的代码：

Imports System.Data.OleDb

Public Class Form1
    Dim sConString As String = "Provider=vfpoledb.1;Data Source=C:\MyDatabase.dbc;Mode=3;"
    Dim con As OleDbConnection = New OleDbConnection(sConString)

    Private Function FetchData()

        con.Open()
        Dim ds As DataSet = New DataSet()
        Dim sSQL As String
        sSQL = "SELECT item_cd, item_desc FROM invent;"

        Dim cmd As OleDbCommand = New OleDbCommand(sSQL, con)
        Dim daInv As OleDbDataAdapter = New OleDbDataAdapter(cmd)
        Dim iRecCount As Integer
        iRecCount = daInv.Fill(ds, "invent")
        Me.DataGridView1.DataSource = ds.Tables("invent").DefaultView
    End Function

    Private Sub btnFetchData_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnFetchData.Click
        Call FetchData()
    End Sub

    Private Sub Form1_FormClosing(ByVal sender As Object, ByVal e As System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing
        con.Close()
        con = Nothing
    End Sub
End Class

Answer 1

此代码是否会更新表并将更改推送回数据库？我不这么认为。我尝试使用SQL Server 2005相同的代码，它不工作（我没有FoxPro数据库）。所以我修改了代码，现在它工作正常。

Imports System.Data.OleDb

Public Class Form1
    Dim sConString As String = "Provider=vfpoledb.1;Data Source=C:\MyDatabase.dbc;Mode=3;"
    Dim con As OleDbConnection = New OleDbConnection(sConString)
    Dim daInv As OleDbDataAdapter
    Dim ds As DataSet = New DataSet()
    Private Sub FetchData()
        con.Open()
        Dim sSQL As String
        sSQL = "SELECT item_cd, item_desc FROM invent;"
        Dim cmd As OleDbCommand = New OleDbCommand(sSQL, con)
        daInv = New OleDbDataAdapter(cmd)
        Dim builder As New OleDbCommandBuilder(daInv)
        Dim iRecCount As Integer
        iRecCount = daInv.Fill(ds, "invent")
        Me.DataGridView1.DataSource = ds.Tables("invent").DefaultView
    End Sub

    Private Sub btnFetchData_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnFetchData.Click
        Call FetchData()
    End Sub

    Private Sub Form1_FormClosing(ByVal sender As Object, ByVal e As System.Windows.Forms.FormClosingEventArgs)
        daInv.Update(ds.Tables("invent"))
        con.Close()
        con = Nothing
    End Sub
End Class

希望它有效：）

Answer 2

我找到了底层问题并解决了它。我正在访问的VFP表没有定义主键。它确实有索引，但它们只是标记为“常规”索引（使用VFP术语）。

我能够使用Ed Leafe网站上的VFP工具调用vRunFox（Visual Run Fox）来修改表结构。我不得不使用一些VFP命令调出Table Designer窗口。

我还必须在FormClosing事件中添加一些代码。这是我的FormClosing事件现在的样子：

    Dim myBuilder As OleDbCommandBuilder = New OleDbCommandBuilder(daInv)
    myBuilder.GetUpdateCommand()
    daInv.UpdateCommand = myBuilder.GetUpdateCommand
    daInv.Update(ds.Tables("invent"))
    con.Close()
    con = Nothing

VB.NET 2008 DataGridView不更新Visual Foxpro数据库

2 个答案: