form4.vb

学生成绩管理系统

Public Class Form4
    Dim tab1 As New DataTable
    Dim tab2 As New DataTable
    Private Sub Form4_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        ComboBox1.Items.Add("学号")
        ComboBox1.Items.Add("课号")
    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Module1.db()
        conn.Open()
        ds.Clear()
       


        If ComboBox1.Text = "学号" Then
            cmd.CommandText = "select stu.sname,sc.cno,course.cname,sc.grade from stu,sc,course where stu.sno=sc.sno and sc.cno=course.cno and stu.sno='" & TextBox1.Text & "'"

            da.SelectCommand = cmd
            da.Fill(ds, "tab1")

            DataGridView1.DataSource = ds.Tables("tab1")
        ElseIf ComboBox1.Text = "课号" Then
            cmd.CommandText = "select  stu.sno,stu.sname,course.cname,sc.grade from stu,sc,course where stu.sno=sc.sno and sc.cno=course.cno and course.cno='" & TextBox1.Text & "'"

            da.SelectCommand = cmd
            da.Fill(ds, "tab2")
            DataGridView1.DataSource = ds.Tables("tab2")

        End If

        conn.Close()
    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        Module1.db()
        conn.Open()


        Dim i As Integer




        If ComboBox1.Text = "学号" Then

            For i = 0 To (ds.Tables("tab1").Rows.Count - 1)
                cmd.CommandText = "update sc set grade = '" & ds.Tables("tab1").Rows(i).Item(3) & "' where sno='" & TextBox1.Text & "' and cno='" & ds.Tables("tab1").Rows(i).Item(1) & "'"
                cmd.ExecuteNonQuery()

            Next
            MsgBox("成功!")

        ElseIf ComboBox1.Text = "课号" Then


            For i = 0 To ds.Tables("tab2").Rows.Count - 1
                cmd.CommandText = "update sc set grade = '" & ds.Tables("tab2").Rows(i).Item(3) & "' where  cno='" & TextBox1.Text & "' and sno='" & ds.Tables("tab2").Rows(i).Item(0) & "'"
                cmd.ExecuteNonQuery()

            Next
            MsgBox("成功!")

        End If





        conn.Close()
    End Sub

    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
        Me.Close()

    End Sub
End Class