浅谈如何使用vb.net从数据库中提取数据

 Imports System.Windows.Forms.Application Module Module1 Sub Main() 'form1 是测试多文档窗口 'Dim frm1 As New Form1() 'frm1.Show() Dim formStudentSysMain As New FormStudentSysMain() formStudentSysMain.Show() Do While True DoEvents() Loop End Sub End Module

 Imports System.Data.SqlClient Public Class FormStudentSysMain Public DBConnstr As String = "Data Source=LJJ-FF\LJJ;Initial Catalog=TestMvc;User ID=sa;Password=111111" Private Sub quitMenuItem_Click(sender As Object, e As EventArgs) Handles quitMenuItem.Click End End Sub Private Sub selectinfoMenuItem_Click(sender As Object, e As EventArgs) Handles selectinfoMenuItem.Click Dim formSearchStudent As New FormSearchStudent formSearchStudent.MdiParent = Me formSearchStudent.WindowState = FormWindowState.Normal formSearchStudent.Show() End Sub Private Sub updateinfoMenuItem1_Click(sender As Object, e As EventArgs) Handles updateinfoMenuItem1.Click Dim formStudentInfo As New FormStudentInfo FormSearchStudent.MdiParent = Me FormSearchStudent.WindowState = FormWindowState.Normal formStudentInfo.Show() End Sub Private Sub importscoreMenuItem_Click(sender As Object, e As EventArgs) Handles importscoreMenuItem.Click Dim formStudentCourse As New FormStudentCourse FormSearchStudent.MdiParent = Me FormSearchStudent.WindowState = FormWindowState.Normal formStudentCourse.Show() End Sub Private Sub cascadeMenuItem_Click(sender As Object, e As EventArgs) Handles cascadeMenuItem.Click Me.LayoutMdi(MdiLayout.Cascade) End Sub Private Sub horizonMenuItem_Click(sender As Object, e As EventArgs) Handles horizonMenuItem.Click Me.LayoutMdi(MdiLayout.TileHorizontal) End Sub Private Sub verticalMenuItem_Click(sender As Object, e As EventArgs) Handles verticalMenuItem.Click Me.LayoutMdi(MdiLayout.TileVertical) End Sub Private Sub FormStudentSysMain_Load(sender As Object, e As EventArgs) Handles MyBase.Load End Sub End Class

 Imports System.Data.SqlClient Public Class FormSearchStudent Private Sub Label1_Click(sender As Object, e As EventArgs) Handles Label1.Click End Sub Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click Dim sqlConStr As String = My.Forms.FormStudentSysMain.DBConnstr Dim sqlStr As String = "select * from student " Dim sqlDataAdapter As New SqlDataAdapter Dim dataSet As New DataSet Dim sqlConnection As New SqlConnection(sqlConStr) If Trim(txtName.Text) <> "" Then sqlStr = sqlStr & "where name like '%" & Trim(txtName.Text) & "%'" End If sqlDataAdapter.SelectCommand = New SqlCommand(sqlStr, sqlConnection) sqlConnection.Open() sqlDataAdapter.Fill(dataSet) sqlConnection.Close() DataGridView1.DataSource = dataSet.Tables(0) End Sub Private Sub FormSearchStudent_Load(sender As Object, e As EventArgs) Handles MyBase.Load End Sub End Class