开发实践教程1：试卷生成系统6.16 试卷类型管理（FormPaperType）

Posted 2021-09-15 VB.Net

版权声明：本文为博主原创文章，转载请在显著位置标明本文出处以及作者网名，未经作者允许不得用于商业目的。

仅管理员可用

增加、修改试卷类型，管理员根据需要进行设置，通常设置好后不再修改。同样，为了防止试卷类型删除引发错误，管理员设置一次后就不再操作或仅能更新、不可删除。

窗体设计如下：

 图1-26

具体代码如下：

Imports System.Data.SqlClient

Public Class FormPaperType
    Dim connection As SqlConnection

    Dim currentTvNode As TreeNode

    Private Sub tvExamType_AfterSelect(sender As Object, e As TreeViewEventArgs) Handles tvExamType.AfterSelect
        Dim selTvNode As TreeNode = e.Node
        If selTvNode.Nodes.Count > 0 Then Exit Sub

        Dim ExamTypeInfo() As String
        ExamTypeInfo = selTvNode.Tag.ToString.Split(",")

        Dim sql As String

        Dim rootindex As String

        Select Case ExamTypeInfo(0)
            Case "root0"
                sql = "select 编号,类型名称 from 考试类型表一级"
                rootindex = "root1"
            Case "root1"
                sql = "select 编号,类型名称 from 考试类型表二级 where 一级类型=" & ExamTypeInfo(1)
                rootindex = "root2"
            Case "root2"
                sql = "select 编号,类型名称 from 考试类型表三级 where 二级类型=" & ExamTypeInfo(1)
                rootindex = "root3"
            Case Else
                Exit Sub
        End Select


        Dim command As New SqlCommand()

        command.CommandText = sql
        command.Connection = connection

        Dim sqlReader As SqlDataReader
        sqlReader = command.ExecuteReader()

        If sqlReader.HasRows Then
            Do While sqlReader.Read
                Dim tvnode As New TreeNode()
                tvnode.Text = sqlReader(1)
                tvnode.Tag = rootindex & "," & sqlReader(0)

                selTvNode.Nodes.Add(tvnode)
            Loop
        End If

        sqlReader.Close()
    End Sub

    Private Sub FormExamType_Load(sender As Object, e As EventArgs) Handles MyBase.Load


        connection = New SqlConnection(databaseConnString)
        connection.Open()


    End Sub









    Private Sub tvExamType_MouseUp(sender As Object, e As MouseEventArgs) Handles tvExamType.MouseUp
        Dim tn As TreeNode
        If e.Button = MouseButtons.Right Then
            tn = tvExamType.GetNodeAt(e.X, e.Y)
            If tn Is Nothing Then
                tvExamType.ContextMenu = Nothing
            Else
                tvExamType.ContextMenuStrip = ContextMenuStrip1
                Dim ExamTypeInfo() As String
                ExamTypeInfo = tn.Tag.ToString.Split(",")

                Select Case ExamTypeInfo(0)
                    Case "root0"
                        tsmiAdd.Enabled = True
                        tsmiEdit.Enabled = False
                    Case "root1", "root2"
                        tsmiAdd.Enabled = True
                        tsmiEdit.Enabled = True
                    Case Else
                        tsmiAdd.Enabled = False
                        tsmiEdit.Enabled = True
                End Select
                currentTvNode = tn
            End If
        End If
    End Sub

    Private Sub tsmiAdd_Click(sender As Object, e As EventArgs) Handles tsmiAdd.Click
        Dim examType As String
        examType = InputBox("输入考试类型", "考试类型设置")
        If examType.Trim = "" Then
            Exit Sub
        End If
        If examType.Trim.Length > 20 Then
            Exit Sub
        End If

        Dim ExamTypeInfo() As String
        ExamTypeInfo = currentTvNode.Tag.ToString.Split(",")

        Dim sql As String
        Select Case ExamTypeInfo(0)
            Case "root0"
                sql = "insert into 考试类型表一级(类型名称) values('" & examType & ")"
            Case "root1"
                sql = "insert into 考试类型表二级(一级类型,类型名称) values(" & ExamTypeInfo(1) & ",'" & examType & "')"
            Case "root2"
                sql = "insert into 考试类型表三级(二级类型,类型名称) values(" & ExamTypeInfo(1) & ",'" & examType & "')"
            Case Else
                Exit Sub
        End Select


        Dim command As New SqlCommand()

        command.CommandText = sql
        command.Connection = connection

        command.ExecuteNonQuery()

        Dim addTvNode As New TreeNode(examType)
        currentTvNode.Nodes.Add(addTvNode)
    End Sub

    Private Sub tsmiEdit_Click(sender As Object, e As EventArgs) Handles tsmiEdit.Click
        Dim examType As String
        examType = InputBox("输入考试类型", "考试类型设置", currentTvNode.Text)
        If examType.Trim = "" Then
            Exit Sub
        End If
        If examType.Trim.Length > 20 Then
            Exit Sub
        End If

        Dim ExamTypeInfo() As String
        ExamTypeInfo = currentTvNode.Tag.ToString.Split(",")

        Dim sql As String
        Select Case ExamTypeInfo(0)
            Case "root1"
                sql = "update 考试类型表一级 set 类型名称='" & examType & "' where 编号=" & ExamTypeInfo(1)
            Case "root2"
                sql = "update 考试类型表二级 set 类型名称='" & examType & "' where 编号=" & ExamTypeInfo(1)
            Case "root3"
                sql = "update 考试类型表三级 set 类型名称='" & examType & "' where 编号=" & ExamTypeInfo(1)
            Case Else
                Exit Sub
        End Select


        Dim command As New SqlCommand()

        command.CommandText = sql
        command.Connection = connection

        command.ExecuteNonQuery()
        currentTvNode.Text = examType
    End Sub

    Private Sub btnClose_Click(sender As Object, e As EventArgs) Handles btnClose.Click
        Me.Close()
    End Sub
End Class

由于.net平台下C#和vb.NET很相似，本文也可以为C#爱好者提供的参考。

学习更多vb.net知识，请参看 vb.net 教程 目录