
Imports System.Data
Imports System.Data.SqlClient
Public Class Form1
Inherits System.Windows.Forms.Form
'数据库连接对象
'错误的写法
'Dim objConnection As SqlConnection = New SqlConnection("server=(local)database=pubsuser id=sapassword=")
'正确写法
Dim objConnection As New SqlConnection("Data Source=127.0.0.1Initial Catalog=pubsuser id=sapassword=")
'数据适配器
Dim objDataAdapter As SqlDataAdapter = New SqlDataAdapter()
'DataSet
Dim objDataSet As DataSet = New DataSet()
Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
'设置查询命令属性
objDataAdapter.SelectCommand = New SqlCommand
objDataAdapter.SelectCommand.Connection = objConnection
objDataAdapter.SelectCommand.CommandText = "select au_lname,au_fname,title,price from authors join titleauthor on authors.au_id=titleauthor.au_id join titles on titleauthor.title_id=titles.title_id order by au_lname,au_fname"
objDataAdapter.SelectCommand.CommandType = CommandType.Text
'打开数据库连接
objConnection.Open()
'填充DataSet对象
objDataAdapter.Fill(objDataSet, "authors")
'关闭数据库连接
objConnection.Close()
'给DataGrid绑定数据
grdAuthorTitles.DataSource = objDataSet
grdAuthorTitles.DataMember = "authors"
'清除
objDataAdapter = Nothing
objConnection = Nothing
End Sub
End Class
//用ADO.net中的Connection进行OLE连接到Access文件,连接字符串例子:connstr="PROVIDER=Microsoft.Jet.OLEDB.4.0DATA Source=DB文件路径Jet OLEDB:Database password=密码"
//再发送Command命令SQL,
Select * from Student_Perfomance where Stu_No='取到的学号'
//再用DataReader取出数据,设置到窗体的控件上。
如果楼主熟悉VB6,可以直接在项目中添加ADODB的Com引用,这样你就可以像VB6那样 *** 作数据库了!另外
.NET
Framework中连接数据库要用到ADO.NET。如果要 *** 作Access数据库,要用到System.Data.OleDb命名空间下的许多类。
比如按楼主所说,“我想在textbox1中显示表一中【一些数据】字段下的第一个内容”:
'首先导入命名空间
Imports
System.Data
Imports
System.Data.OleDb
'然后在某一个事件处理程序中写:
Dim
conn
As
New
OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0Data
Source=数据库.accdbJet
OLEDB:Database
Password=MyDbPassword")
Dim
command
As
New
OleDbCommand("Select
*
From
数据表",
conn)
conn.Open()
'打开数据库连接
Dim
reader
As
OleDbDataReader
=
command.ExecuteReader()
'执行SQL语句,返回OleDbDataReader
对象
Do
While
reader.Read()
'读取一条数据
textbox1.Text
+=
reader("一些数据")
&
VbCrLf
Loop
reader.Close()
'关闭OleDbDataReader
conn.Close()
'关闭连接
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