VB.NET 连接数据库后的操作

ACmd.CommandText = AFind 下面要加上一句执行

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ACmd.ExecuteNonQuery()

-------------------------------------

要写查询到控件DataGridView的话，可以这样做：.net2.0或以上的环境中：

Dim AConnect As OleDb.OleDbConnection

Dim ACmd As OleDb.OleDbCommand

Dim dtResult As DataTable=new DataTable()

Dim ConnectStr As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" Application.StartupPath "\Enroll.mdb"

Dim AFind As String = "SELECT * FROM rj"

AConnect = New OleDb.OleDbConnection(ConnectStr)

AConnect.Open()

ACmd = New OleDb.OleDbCommand(AFind, AConnect)

ACmd.CommandText = AFind

Dim ADr as OleDb.OleDbDataReader=ACmd.ExcuteReader()

dtResult.Load(ADr)

AConnect.Close()

DataGridView.DataSource=dtResult

---------

希望能符合你的需求

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数据库操作

参考一下下面这段代码就可以了。

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

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