VB.NET 连接数据库后的操作

ACmd.CommandText = AFind 下面要加上一句执行
ACmd.ExecuteNonQuery()
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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
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希望能符合你的需求

下面是我的两个函数，希望对你又帮助：
Function Getdata(ByVal Sqlstr As String) As DataTable '取得数据
Dim Connstr As String = "provider=SQLOLEDB;data source=" & ServerName & ";initial catalog=" & DBName & ";user id =" & DBUserName & ";password=" & DBUserPwd
Dim SqlConn As New OleDb.OleDbConnection(Connstr)
Dim SqlCmd As New OleDb.OleDbCommand(Sqlstr, SqlConn)
Dim TmpDst As New DataSet
Dim TmpAda As New OleDb.OleDbDataAdapter
TmpAda.TableMappings.Add("table", "temp")
TmpAda.SelectCommand = SqlCmd
SqlConn.Open()
SqlCmd.ExecuteNonQuery()
SqlConn.Close()
TmpAda.Fill(TmpDst, "temp")
Return TmpDst.Tables("temp")
End Function

Function Gengxindata(ByVal Sqlstr As String) As Boolean '更新数据
Try
Dim Connstr As String = "Provider=SQLOLEDB;data source=" & ServerName & ";initial catalog=" & DBName & ";user id =" & DBUserName & ";password=" & DBUserPwd
Dim SqlConn As New OleDb.OleDbConnection(Connstr)
Dim SqlCmd As New OleDb.OleDbCommand(Sqlstr, SqlConn)
SqlConn.Open()
SqlCmd.ExecuteNonQuery()
SqlConn.Close()
Return True
Catch ex As Exception
MessageBox.Show(ex.Message)
Return False
End Try
End Function

看你连接的是access数据库，只要把函数里面的链接字符串改一下就可以了！
对数据库的查询返回结果：
dim TSqlStr1 as string="你的sql语句"
datagridview.datasource=getdata(TSqlStr1)'getdata()是上面第一个函数

好复杂的问题了。。。
百度上是不太可能问得到，建议楼主到专业点的论坛上发帖问比较好~~