vb.net打开数据库 VB访问数据库

vb.net数据库操作

参考一下下面这段代码就可以了。

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Imports System.Data

'引入数据库操作类命名空间

Imports System.Data.OleDb

'引入ADO.NET操作命名空间

Public Class FrmModifystInfo

Inherits System.Windows.Forms.Form

Public ADOcmd As OleDbDataAdapter

Public ds As DataSet = New DataSet()

'建立DataSet对象

Public mytable As Data.DataTable

'建立表单对象

Public myrow As Data.DataRow

'建立数据行对象

Public rownumber As Integer

'定义一个整型变量来存放当前行数

Public SearchSQL As String

Public cmd As OleDbCommandBuilder

'======================================================

#Region " Windows 窗体设计器生成的代码 "

#End Region

'======================================================

Private Sub FrmModifystInfo_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Load

'窗体的载入

TxtSID.Enabled = False

TxtName.Enabled = False

ComboSex.Enabled = False

TxtBornDate.Enabled = False

TxtClassno.Enabled = False

TxtRuDate.Enabled = False

TxtTel.Enabled = False

TxtAddress.Enabled = False

TxtComment.Enabled = False '设置信息为只读

Dim tablename As String = "student_Info "

SearchSQL = "select * from student_Info "

ExecuteSQL(SearchSQL, tablename) '打开数据库

ShowData() '显示记录

End Sub

Private Sub ShowData()

'在窗口中的textbox中显示数据

myrow = mytable.Rows.Item(rownumber)

TxtSID.Text = myrow.Item(0).ToString

TxtName.Text = myrow.Item(1).ToString

ComboSex.Text = myrow.Item(2).ToString

TxtBornDate.Text = Format(myrow.Item(3), "yyyy-MM-dd ")

TxtClassno.Text = myrow.Item(4).ToString

TxtTel.Text = myrow.Item(5).ToString

TxtRuDate.Text = Format(CDate(myrow.Item(6)), "yyyy-MM-dd ")

TxtAddress.Text = myrow.Item(7).ToString

TxtComment.Text = myrow.Item(8).ToString

End Sub

Private Sub BtFirst_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtFirst.Click

'指向第一条数据

rownumber = 0

ShowData()

End Sub

Private Sub BtPrev_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtPrev.Click

'指向上一条数据

BtNext.Enabled = True

rownumber = rownumber - 1

If rownumber 0 Then

rownumber = 0 '如果到达记录的首部，行号设为零

BtPrev.Enabled = False

End If

ShowData()

End Sub

Private Sub BtNext_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtNext.Click

'指向上一条数据

BtPrev.Enabled = True

rownumber = rownumber + 1

If rownumber mytable.Rows.Count - 1 Then

rownumber = mytable.Rows.Count - 1 '判断是否到达最后一条数据

BtNext.Enabled = False

End If

ShowData()

End Sub

Private Sub BtLast_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtLast.Click

'指向最后一条数据

rownumber = mytable.Rows.Count - 1

ShowData()

End Sub

Private Sub BtDelete_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtDelete.Click

mytable.Rows.Item(rownumber).Delete() '删除记录

If MsgBox( "确定要删除改记录吗？ ", MsgBoxStyle.OKCancel + vbExclamation, "警告 ") = MsgBoxResult.OK Then

cmd = New OleDbCommandBuilder(ADOcmd)

'使用自动生成的SQL语句

ADOcmd.Update(ds, "student_Info ")

BtNext.PerformClick()

End If

End Sub

Private Sub BtModify_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtModify.Click

TxtSID.Enabled = False '关键字段只读

TxtName.Enabled = True '可读写

ComboSex.Enabled = True

TxtBornDate.Enabled = True

TxtClassno.Enabled = True

TxtRuDate.Enabled = True

TxtTel.Enabled = True

TxtAddress.Enabled = True

TxtComment.Enabled = True

End Sub

Private Sub BtUpdate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtUpdate.Click

If Not Testtxt(TxtName.Text) Then

MsgBox( "请输入姓名！ ", vbOKOnly + vbExclamation, "警告 ")

TxtName.Focus()

Exit Sub

End If

If Not Testtxt(ComboSex.Text) Then

MsgBox( "请选择性别！ ", vbOKOnly + vbExclamation, "警告 ")

ComboSex.Focus()

Exit Sub

End If

If Not Testtxt(TxtClassno.Text) Then

MsgBox( "请选择班号！ ", vbOKOnly + vbExclamation, "警告 ")

TxtClassno.Focus()

Exit Sub

End If

If Not Testtxt(TxtTel.Text) Then

MsgBox( "请输入联系电话！ ", vbOKOnly + vbExclamation, "警告 ")

TxtTel.Focus()

Exit Sub

End If

If Not Testtxt(TxtAddress.Text) Then

MsgBox( "请输入家庭住址！ ", vbOKOnly + vbExclamation, "警告 ")

TxtAddress.Focus()

Exit Sub

End If

If Not IsNumeric(Trim(TxtSID.Text)) Then

MsgBox( "请输入数字学号！ ", vbOKOnly + vbExclamation, "警告 ")

Exit Sub

TxtSID.Focus()

End If

If Not IsDate(TxtBornDate.Text) Then

MsgBox( "出生时间应输入日期格式（yyyy-mm-dd）！ ", vbOKOnly + vbExclamation, "警告 ")

Exit Sub

TxtBornDate.Focus()

End If

If Not IsDate(TxtRuDate.Text) Then

MsgBox( "入校时间应输入日期格式（yyyy-mm-dd）！ ", vbOKOnly + vbExclamation, "警告 ")

TxtRuDate.Focus()

Exit Sub

End If

myrow.Item(0) = Trim(TxtSID.Text)

myrow.Item(1) = Trim(TxtName.Text)

myrow.Item(2) = Trim(ComboSex.Text)

myrow.Item(3) = Trim(TxtBornDate.Text)

myrow.Item(4) = Trim(TxtClassno.Text)

myrow.Item(5) = Trim(TxtTel.Text)

myrow.Item(6) = Trim(TxtRuDate.Text)

myrow.Item(7) = Trim(TxtAddress.Text)

myrow.Item(8) = Trim(TxtComment.Text)

mytable.GetChanges()

cmd = New OleDbCommandBuilder(ADOcmd)

'使用自动生成的SQL语句

ADOcmd.Update(ds, "student_Info ")

'对数据库进行更新

MsgBox( "修改学籍信息成功！ ", vbOKOnly + vbExclamation, "警告 ")

TxtName.Enabled = False

ComboSex.Enabled = False

TxtBornDate.Enabled = False

TxtClassno.Enabled = False

TxtRuDate.Enabled = False

TxtTel.Enabled = False

TxtAddress.Enabled = False

TxtComment.Enabled = False '重新设置信息为只读

End Sub

Private Sub BtCancel_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtCancel.Click

TxtSID.Enabled = False

TxtName.Enabled = False

ComboSex.Enabled = False

TxtBornDate.Enabled = False

TxtClassno.Enabled = False

TxtRuDate.Enabled = False

TxtTel.Enabled = False

TxtAddress.Enabled = False

TxtComment.Enabled = False

End Sub

Public Function ExecuteSQL(ByVal SQL As String, ByVal table As String)

Try

'建立ADODataSetCommand对象

'数据库查询函数

ADOcmd = New OleDbDataAdapter(SQL, "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=c:\student.mdb ")

'建立ADODataSetCommand对象

ADOcmd.Fill(ds, table) '取得表单

mytable = ds.Tables.Item(0) '取得名为table的表

rownumber = 0 '设置为第一行

myrow = mytable.Rows.Item(rownumber)

'取得第一行数据

Catch

MsgBox(Err.Description)

End Try

End Function

End Class

请采纳。

vb.net 怎么操作数据库

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那样操作数据库了！

另外

.NET Framework中连接数据库要用到ADO.NET。如果要操作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.12.0;Data Source=数据库.accdb;Jet 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

VB.NET怎么访问数据库

以下示例代码来自msdn

Option Explicit On

Option Strict On

Imports System

Imports System.Data

Imports System.Data.SqlClient

Public Class Program

Public Shared Sub Main()

Dim connectionString As String = _

"Data Source=(local);Initial Catalog=Northwind;" _

"Integrated Security=true"

' Provide the query string with a parameter placeholder.

Dim queryString As String = _

"SELECT ProductID, UnitPrice, ProductName from dbo.Products " _

"WHERE UnitPrice @pricePoint " _

"ORDER BY UnitPrice DESC;"

' Specify the parameter value.

Dim paramValue As Integer = 5

' Create and open the connection in a using block. This

' ensures that all resources will be closed and disposed

' when the code exits.

Using connection As New SqlConnection(connectionString)

' Create the Command and Parameter objects.

Dim command As New SqlCommand(queryString, connection)

command.Parameters.AddWithValue("@pricePoint", paramValue)

' Open the connection in a try/catch block.

' Create and execute the DataReader, writing the result

' set to the console window.

Try

connection.Open()

Dim dataReader As SqlDataReader = _

command.ExecuteReader()

Do While dataReader.Read()

Console.WriteLine( _

vbTab "{0}" vbTab "{1}" vbTab "{2}", _

dataReader(0), dataReader(1), dataReader(2))

Loop

dataReader.Close()

Catch ex As Exception

Console.WriteLine(ex.Message)

End Try

Console.ReadLine()

End Using

End Sub

End Class

----------------------回答补充------------------------------------

上面的源码你应该仔细看看，因为这是微软的示例代码，是通用的，写得很规范。

至于你的特殊的问题，在vb2010中可以不用一句代码把你的表显示在窗体上。

vb.net 中如何使用SQL语句查询数据库中的数据

1、首先打开Visual Studio 2008代码窗口，添加引用。

2、输入以下代码：Public conn1  As SqlConnection = New SqlConnection 。

3、声明关键字 Public；（因为是全局变量，所以用Public 来声明）。

4、如果SQL 数据库就在本机，则用以下代码连接。

5、如果代码太长，影响可读性，可以用空格加"_"后，回车换行即可。

初学vb.net，打开数据库的时候，运行到connStr.Open()程序好像死掉了，这是怎么回事？

connStr.ConnectionString = "Data Source=localhost;Initial Catalog=test1;user id=sa;password=123456"

一般是你这里的设置写的不对导致找不到数据服务器 导致一直处于连接中的状态，需要等待超时 才会有反应