實現數據庫的增刪改查（ADO.Net）

 //vb實現數據庫的連接，修改，刪除，插入（ADO.Net） - 雲代碼 http://yuncode.net/code/c_508403a91ab6b23

Public Class 全部學生信息

     Dim conn As New SqlConnection

     Dim rs As New SqlDataAdapter

     'Dim dt As New DataTable

     Dim ds As New DataSet

     Public Function connect_db() As SqlConnection

         Dim constr As String

         constr = "Server=PC-201105311336\SQLEXPRESS;uid=sa;pwd=123456;database=jiaxiaoai"

         'rs.Fill(dataset, "student")

         conn = New SqlConnection(constr)

         conn.Open()

         connect_db = conn

     End Function

     Private Sub 全部學生信息_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Load'窗口初始化函數

         Dim sql As String

         Dim dt As New DataTable

         sql = "select * from student"

         conn = connect_db()

         rs = New SqlDataAdapter(sql, conn)

         conn.Close()

         rs.Fill(dt) '填充表

         DataGridView1.DataSource = dt '將表中的數據顯示到datagridView控件中，綁定數據

         DataGridView1.Columns(0).HeaderText = "學號" '設置列名

         DataGridView1.Columns(1).HeaderText = "姓名"

         DataGridView1.Columns(2).HeaderText = "年齡"

         DataGridView1.Columns(3).HeaderText = "成績"

         rownum.Text = Str(DataGridView1.RowCount) '獲取行數

         xuehaotext.Text = DataGridView1.Rows(0).Cells(0).Value '獲取datagridview中的某個值

         nametext.Text = DataGridView1.Rows(0).Cells(1).Value

         If (DataGridView1.Rows(0).Cells(2).Value = 0) Then

             agetext.Text = ""

         Else

             agetext.Text = Str(DataGridView1.Rows(0).Cells(2).Value)

         End If

         If (DataGridView1.Rows(0).Cells(3).Value = 0) Then

             scoretext.Text = ""

         Else

             scoretext.Text = Str(DataGridView1.Rows(0).Cells(3).Value)

         End If

     End Sub

     Private Sub selectbtn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handlesselectbtn.Click

         Dim sql As String

         Dim dt As New DataTable

         sql = "select * from student where name like 'l%'"

         conn = connect_db()

         rs = New SqlDataAdapter(sql, conn)

         conn.Close()

         rs.Fill(dt) '填充表

         DataGridView1.DataSource = dt '將表中的數據顯示到datagridView控件中，綁定數據

         DataGridView1.Columns(0).HeaderText = "學號" '設置列名

         DataGridView1.Columns(1).HeaderText = "姓名"

         DataGridView1.Columns(2).HeaderText = "年齡"

         DataGridView1.Columns(3).HeaderText = "成績"

         rownum.Text = Str(DataGridView1.RowCount) '獲取行數

         xuehaotext.Text = DataGridView1.Rows(0).Cells(0).Value '獲取datagridview中的某個值

         nametext.Text = DataGridView1.Rows(0).Cells(1).Value

         If (DataGridView1.Rows(0).Cells(2).Value = 0) Then

             agetext.Text = ""

         Else

             agetext.Text = Str(DataGridView1.Rows(0).Cells(2).Value)

         End If

         If (DataGridView1.Rows(0).Cells(3).Value = 0) Then

             scoretext.Text = ""

         Else

             scoretext.Text = Str(DataGridView1.Rows(0).Cells(3).Value)

         End If

     End Sub

     Private Sub DataGridView1_CellMouseClick(ByVal sender As System.Object, ByVal e AsSystem.Windows.Forms.DataGridViewCellMouseEventArgs) Handles DataGridView1.CellMouseClick '鼠標點擊單元格觸發事件

         'DataGridView1.CurrentRow.Index獲取當前單元格的行號

         xuehaotext.Text = DataGridView1.Rows(DataGridView1.CurrentRow.Index).Cells(0).Value '獲取datagridview中的某個值

         nametext.Text = DataGridView1.Rows(DataGridView1.CurrentRow.Index).Cells(1).Value

         If (DataGridView1.Rows(DataGridView1.CurrentRow.Index).Cells(2).Value = 0) Then

             agetext.Text = ""

         Else

             agetext.Text = Str(DataGridView1.Rows(DataGridView1.CurrentRow.Index).Cells(2).Value)

         End If

         If (DataGridView1.Rows(DataGridView1.CurrentRow.Index).Cells(3).Value = 0) Then

             scoretext.Text = ""

         Else

             scoretext.Text = Str(DataGridView1.Rows(DataGridView1.CurrentRow.Index).Cells(3).Value)

         End If

     End Sub

     Private Sub updatebtn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handlesupdatebtn.Click

         Dim sql As String

         Dim row As String

         Dim dc As New SqlCommand

         Dim age

         If agetext.Text = "" Then

             age = 0

         Else

             age = Val(agetext.Text)

         End If

         sql = "update student set sid='" & xuehaotext.Text & "', name='" & nametext.Text & "',age='" & age & "',score='" & scoretext.Text & "' where sid='" & DataGridView1.Rows(DataGridView1.CurrentRow.Index).Cells(0).Value & "'"

         conn = connect_db()

         dc = New SqlCommand(sql, conn)

         row = dc.ExecuteNonQuery()

         conn.Close()

         If (row > 0) Then

             MsgBox("修改成功")

         Else

             MsgBox("修改失敗")

         End If

         DataGridView1.Rows(DataGridView1.CurrentRow.Index).Cells(0).Value = xuehaotext.Text

         DataGridView1.Rows(DataGridView1.CurrentRow.Index).Cells(1).Value = nametext.Text

         DataGridView1.Rows(DataGridView1.CurrentRow.Index).Cells(2).Value = agetext.Text

         DataGridView1.Rows(DataGridView1.CurrentRow.Index).Cells(3).Value = scoretext.Text

     End Sub

     Private Sub insertbtn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handlesinsertbtn.Click

         Dim sql As String

         Dim row As String

         Dim dc As New SqlCommand

         Dim age

         If agetext.Text = "" Then

             age = 0

         Else

             age = Val(agetext.Text)

         End If

         sql = "insert into student values('" & xuehaotext.Text & "', '" & nametext.Text & "','" & age &"','" & scoretext.Text & "')"

         conn = connect_db()

         dc = New SqlCommand(sql, conn)

         row = dc.ExecuteNonQuery()

         'conn.Close()

         If (row > 0) Then

             MsgBox("插入成功")

         Else

             MsgBox("插入失敗")

         End If

         Dim dt As New DataTable

         sql = "select * from student"

         'conn = connect_db()

         rs = New SqlDataAdapter(sql, conn)

         conn.Close()

         rs.Fill(dt) '填充表

         DataGridView1.DataSource = dt '將表中的數據顯示到datagridView控件中，綁定數據

         DataGridView1.Columns(0).HeaderText = "學號" '設置列名

         DataGridView1.Columns(1).HeaderText = "姓名"

         DataGridView1.Columns(2).HeaderText = "年齡"

         DataGridView1.Columns(3).HeaderText = "成績"

         rownum.Text = Str(DataGridView1.RowCount) '獲取行數

         xuehaotext.Text = DataGridView1.Rows(0).Cells(0).Value '獲取datagridview中的某個值

         nametext.Text = DataGridView1.Rows(0).Cells(1).Value

         If (DataGridView1.Rows(0).Cells(2).Value = 0) Then

             agetext.Text = ""

         Else

             agetext.Text = Str(DataGridView1.Rows(0).Cells(2).Value)

         End If

         If (DataGridView1.Rows(0).Cells(3).Value = 0) Then

             scoretext.Text = ""

         Else

             scoretext.Text = Str(DataGridView1.Rows(0).Cells(3).Value)

         End If

     End Sub

     Private Sub deletebtn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handlesdeletebtn.Click

         Dim sql As String

         Dim row As String

         Dim dc As New SqlCommand

         Dim age

         If agetext.Text = "" Then

             age = 0

         Else

             age = Val(agetext.Text)

         End If

         sql = "delete student where sid='" & DataGridView1.Rows(DataGridView1.CurrentRow.Index).Cells(0).Value & "'and name='" & DataGridView1.Rows(DataGridView1.CurrentRow.Index).Cells(1).Value & "'"

         conn = connect_db()

         dc = New SqlCommand(sql, conn)

         row = dc.ExecuteNonQuery()

         'conn.Close()

         If (row > 0) Then

             MsgBox("刪除成功")

         Else

             MsgBox("刪除失敗")

         End If

         Dim dt As New DataTable

         sql = "select * from student"

         conn = connect_db()

         rs = New SqlDataAdapter(sql, conn)

         conn.Close()

         rs.Fill(dt) '填充表

         DataGridView1.DataSource = dt '將表中的數據顯示到datagridView控件中，綁定數據

         DataGridView1.Columns(0).HeaderText = "學號" '設置列名

         DataGridView1.Columns(1).HeaderText = "姓名"

         DataGridView1.Columns(2).HeaderText = "年齡"

         DataGridView1.Columns(3).HeaderText = "成績"

         rownum.Text = Str(DataGridView1.RowCount) '獲取行數

         xuehaotext.Text = DataGridView1.Rows(0).Cells(0).Value '獲取datagridview中的某個值

         nametext.Text = DataGridView1.Rows(0).Cells(1).Value

         If (DataGridView1.Rows(0).Cells(2).Value = 0) Then

             agetext.Text = ""

         Else

             agetext.Text = Str(DataGridView1.Rows(0).Cells(2).Value)

         End If

         If (DataGridView1.Rows(0).Cells(3).Value = 0) Then

             scoretext.Text = ""

         Else

             scoretext.Text = Str(DataGridView1.Rows(0).Cells(3).Value)

         End If

     End Sub

 End Class