VB.net数据库编程（01）：简单的入门实例--连接到Access文件

先来一个简单的实例。

VB 2012

SQl server 2012

Access文件：http://download.csdn/detail/dzweather/5042992

（两个版本，2003,2012,任选一个）

根据前面ADO入门的介绍，我们知道了连接的过程。

AccessFile文件，针对的是Oledb，所以首先应引用。

然后，定义三个对象，在实例中再进行创建（这样可以节约点资源）

特别注意的是，里面没有了cmd过程，我感觉这样的入门适合我学习。

这个例子，就一个窗体，一个datagridview（不绑定，用代码绑定），然后就是几句代码，很简单。

[vb] view plain copy print ?

Imports System.Data.OleDb
Public Class Form1
Dim cn As OleDbConnection
Dim da As OleDbDataAdapter
Dim ds As DataSet
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Dim cnStr As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=D:\persons.mdb;Persist Security Info=False"
cn = New OleDbConnection(cnStr)
Dim sql As String = "select * from grade"
da = New OleDbDataAdapter(sql, cn)
ds = New DataSet
da.Fill(ds, "grade")
DataGridView1.DataSource = ds.Tables(0)
End Sub
End Class

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上面的有点简单，但流程清晰。与我们实际应用有很大距离。

下面再跨一步，接近实际应用，即变得较为灵活点：

[vb] view plain copy print ?

Imports System.Data.OleDb
Public Class Form1
Dim cn As OleDbConnection
Dim da As OleDbDataAdapter
Dim ds As DataSet
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Dim cnStr As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=D:\persons.mdb;Persist Security Info=False"
cn = New OleDbConnection(cnStr)
Dim sql As String = "select * from grade"
da = New OleDbDataAdapter(sql, cn)
ds = New DataSet
da.Fill(ds, "grade")
DataGridView1.DataSource = ds.Tables(0)
End Sub
Private Sub btnQuery_Click(sender As Object, e As EventArgs) Handles btnQuery.Click
Dim cnStr As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=D:\persons.mdb;Persist Security Info=False"
cn = New OleDbConnection(cnStr)
Dim sql As String = TextBox1.Text
da = New OleDbDataAdapter(sql, cn)
ds = New DataSet
da.Fill(ds, "grade")
DataGridView1.DataSource = ds.Tables(0)
End Sub
Private Sub btnQueyName_Click(sender As Object, e As EventArgs) Handles btnQueyName.Click
Dim cnStr As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=D:\persons.mdb;Persist Security Info=False"
cn = New OleDbConnection(cnStr)
Dim sql As String = "select * from grade where 姓名 like " & "'%" & TextBox2.Text & "%'"
da = New OleDbDataAdapter(sql, cn)
ds = New DataSet
da.Fill(ds, "grade")
DataGridView1.DataSource = ds.Tables(0)
End Sub
End Class