如何使用同一SQL Server数据库中多个表的数据有条件地填充组合框

本文介绍了如何使用同一SQL Server数据库中多个表的数据有条件地填充组合框的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述 我有2个组合框，第一个在运行时填充最多4个元素。我希望第二个组合框根据所选项目填充4个表中的1个表中的数据。 这是我的代码： Imports System.Data.SqlClient Public Class MealMenuForm     Dim connection As New SqlConnection（"Server = DESKTOP-1373H91; Initial Catalog = MealPreOrderSystem; Integrated Security = True"）     Private Sub MealMenuForm_Load（发件人为对象，e为EventArgs）处理MyBase.Load         cbxType.Items.Add（" Meal"）         cbxType.Items.Add（" Dessert"）         cbxType.Items.Add（" Soft Drink"）         cbxType.Items.Add（" Alcoholic"）    结束次     Private Sub cbxItemName_SelectedIndexChanged（sender As Object，e As EventArgs）处理cbxItemName.SelectedIndexChanged         Dim mealsNames As New String（"SELECT MealName FROM dbo.Dishes"）         Dim dessertsNames As New String（"SELECT DessertName FROM dbo.Desserts"）         Dim sDrinksNames As New String（"SELECT DrinkName FROM dbo.SoftDrinks"）        将aDrinksNames调暗为新字符串（"SELECT DrinkName FROM dbo.AlcoholicDrinks"）         connection.Open（）         Dim cmdMeals，cmdDesserts，cmdsDrinks，cmdaDrinks As SqlCommand         cmdMeals = New SqlCommand（mealsNames，connection）         cmdDesserts =新的SqlCommand（dessertsNames，连接）         cmdsDrinks =新的SqlCommand（sDrinksNames，连接）         cmdaDrinks =新的SqlCommand（aDrinksNames，连接）         Dim readerMeals，readerDserts，readersDrinks，readeraDrinks As SqlDataReader        尝试            如果cbxType.SelectedItem =" Meal"然后是                readerMeals = cmdMeals.ExecuteReader（）                虽然readerMeals.Read                     cbxItemName.Items.Add（readerMeals.Item（" MealName"）））                结束时                 connection.Close（）                 connection.Dispose（）                 connection = Nothing             ElseIf cbxType.SelectedItem =" Dessert"然后是                readerDesserts = cmdDesserts.ExecuteReader（）                虽然readerDesserts.Read                     cbxItemName.Items.Add（readerDesserts.Item（" DessertName"）））                结束时                connection.Close（）                 connection.Dispose（）                 connection = Nothing             ElseIf cbxType.SelectedItem =" Soft Drink"然后是                readersDrinks = cmdsDrinks.ExecuteReader                虽然readerDrinks.Read                     cbxItemName.Items.Add（readersDrinks.Item（" DrinkName"）））$                 结束时                connection.Close（）                 connection.Dispose（）                 connection = Nothing             ElseIf cbxType.SelectedItem =" Alcoholic"然后是                readeraDrinks = cmdsDrinks.ExecuteReader                 readeraDrinks.Read                     cbxItemName.Items.Add（readeraDrinks.Item（" DrinkName"）））$                 结束时                connection.Close（）                 connection.Dispose（）                 connection = Nothing            结束如果         C ex ex As Exception             MsgBox（ex.ToString）        最后为            connection.Close（）             connection.Dispose（）             connection = Nothing        结束尝试    结束点¥结束类解决方案 I have 2 comboboxes, where the 1st one is filled at runtime with up to 4 elements. I want the 2nd combobox to be filled with data from 1 of 4 tables based on the item chosen.Here is my code:Imports System.Data.SqlClientPublic Class MealMenuForm    Dim connection As New SqlConnection("Server = DESKTOP-1373H91; Initial Catalog = MealPreOrderSystem; Integrated Security = True")    Private Sub MealMenuForm_Load(sender As Object, e As EventArgs) Handles MyBase.Load        cbxType.Items.Add("Meal")        cbxType.Items.Add("Dessert")        cbxType.Items.Add("Soft Drink")        cbxType.Items.Add("Alcoholic")    End Sub    Private Sub cbxItemName_SelectedIndexChanged(sender As Object, e As EventArgs) Handles cbxItemName.SelectedIndexChanged        Dim mealsNames As New String("SELECT MealName FROM dbo.Dishes")        Dim dessertsNames As New String("SELECT DessertName FROM dbo.Desserts")        Dim sDrinksNames As New String("SELECT DrinkName FROM dbo.SoftDrinks")        Dim aDrinksNames As New String("SELECT DrinkName FROM dbo.AlcoholicDrinks")        connection.Open()        Dim cmdMeals, cmdDesserts, cmdsDrinks, cmdaDrinks As SqlCommand        cmdMeals = New SqlCommand(mealsNames, connection)        cmdDesserts = New SqlCommand(dessertsNames, connection)        cmdsDrinks = New SqlCommand(sDrinksNames, connection)        cmdaDrinks = New SqlCommand(aDrinksNames, connection)        Dim readerMeals, readerDesserts, readersDrinks, readeraDrinks As SqlDataReader        Try            If cbxType.SelectedItem = "Meal" Then                readerMeals = cmdMeals.ExecuteReader()                While readerMeals.Read                    cbxItemName.Items.Add(readerMeals.Item("MealName"))                End While                connection.Close()                connection.Dispose()                connection = Nothing            ElseIf cbxType.SelectedItem = "Dessert" Then                readerDesserts = cmdDesserts.ExecuteReader()                While readerDesserts.Read                    cbxItemName.Items.Add(readerDesserts.Item("DessertName"))                End While                connection.Close()                connection.Dispose()                connection = Nothing            ElseIf cbxType.SelectedItem = "Soft Drink" Then                readersDrinks = cmdsDrinks.ExecuteReader                While readersDrinks.Read                    cbxItemName.Items.Add(readersDrinks.Item("DrinkName"))                End While                connection.Close()                connection.Dispose()                connection = Nothing            ElseIf cbxType.SelectedItem = "Alcoholic" Then                readeraDrinks = cmdsDrinks.ExecuteReader                While readeraDrinks.Read                    cbxItemName.Items.Add(readeraDrinks.Item("DrinkName"))                End While                connection.Close()                connection.Dispose()                connection = Nothing            End If        Catch ex As Exception            MsgBox(ex.ToString)        Finally            connection.Close()            connection.Dispose()            connection = Nothing        End Try    End SubEnd Class 解决方案 这篇关于如何使用同一SQL Server数据库中多个表的数据有条件地填充组合框的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！