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c# - UWP。如何将数据传递到我的数据库然后填充网格？

问题描述

我在使用 UWP 时遇到了一些困难，想知道是否有人可以提供帮助？C♯在这里很新。

基本上我有一个添加员工的页面，我认为输入的数据在逻辑上应该发送到一个名为“Person”的类，然后再添加到数据库中（但我知道什么哈哈哈！）。然后数据库需要在主页面上填充一个网格。

所以，主要的两个问题是，如何让 Person 类中的数据填充数据库并依次填充主页上的网格？以及如何从不同的页面添加到班级人员？

这是我尝试的地方：

这就是我的 Person 类：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace TestApp2
{
    using static DB;
    class Person 
    {
            public int PersonId { get; set; }
            public int DepartmentId { get; set; }
            public string FirstName { get; set; }
            public string LastName { get; set; }
            public string Position { get; set; }
            public string Address { get; set; }
            public double PayratePH { get; set; }
            public double Holiday { get; set; }
            public string TaxCode { get; set; }

        private List<String> Grab_Entries()
        {
            List<String> entries = new List<string>();
            using (SqliteConnection db = new SqliteConnection("Filename=sqliteSample.db"))
            {
                db.Open();
                SqliteCommand selectCommand = new SqliteCommand("SELECT First_Name from EmployeeTable", db);
                SqliteDataReader query;
                try
                {
                    query = selectCommand.ExecuteReader();
                }
                catch (SqliteException)
                {
                    //Handle error
                    return entries;
                }
                while (query.Read())
                {
                    entries.Add(query.GetString(0));
                    
                }
                db.Close();
            }
            return entries;
            
        }
        
    }

}

这是我的数据库类：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Windows.UI.Xaml;

namespace TestApp2
{
    public static class DB
    {
        private static SuspendingEventHandler App_Suspending;

        public static void database()
        {
            Application.Current.Suspending += new SuspendingEventHandler(App_Suspending);
            using (SqliteConnection db = new SqliteConnection("Filename=sqliteSample.db"))
            {
                //Creation of the database table
                db.Open();
                String tableCommand1 = "CREATE TABLE IF NOT EXISTS EmployeeTable (Employee_ID INTEGER PRIMARY KEY AUTOINCREMENT, First_Name NVARCHAR(20) NULL, Last_Name NVARCHAR(40) NULL, Address NVARCHAR(50) NULL , Position NVARCHAR(20) NULL, Pay_Rate DOUBLE NULL, Tax_Code NVARCHAR(10) NULL, Sex NVARCHAR(20), NI NVACHAR(10), Emergency_Details NVARCHAR(100)";
                
                SqliteCommand createTable = new SqliteCommand(tableCommand1, db);
                
                try
                {
                    createTable.ExecuteReader();
                }
                catch (SqliteException)
                {
                    //Do nothing
                }
            }
        }
    }
}

最后是我的主页。注释掉的部分是我测试我是否可以填充 xaml 网格（如果有帮助，我正在使用社区开发网格？https://docs.microsoft.com/en-us/windows/communitytoolkit/controls/datagrid_guidance /datagrid_basics )

using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices.WindowsRuntime;
using Windows.Foundation;
using Windows.Foundation.Collections;
using Windows.UI.Popups;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Controls.Primitives;
using Windows.UI.Xaml.Data;
using Windows.UI.Xaml.Input;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Navigation;



// The Blank Page item template is documented at https://go.microsoft.com/fwlink/?LinkId=402352&clcid=0x409

namespace TestApp2
{
    

    public class Department
    {
        public int DepartmentId { get; set; }
        public string DepartmentName { get; set; }
    }

    //public class Person
    //{
    //    public int PersonId { get; set; }
    //    public int DepartmentId { get; set; }
    //    public string FirstName { get; set; }
    //    public string LastName { get; set; }
    //    public string Position { get; set; }
    //    public string Address { get; set; }
    //    public double PayratePH { get; set; }
    //    public double Holiday { get; set; }
    //    public string TaxCode { get; set; }


    //}
    /// <summary>
    /// An empty page that can be used on its own or navigated to within a Frame.
    /// </summary>
    public sealed partial class MainPage : Page
    {

        public List<Department> Departments { get; set; }
        List<Person> persons;

        public MainPage()
        {
            this.InitializeComponent();
            persons = new List<Person>();

        //    Departments = new List<Department>
        //{
        //    new Department {DepartmentId = 1, DepartmentName = "R&D"},
        //    new Department {DepartmentId = 2, DepartmentName = "Finance"},
        //    new Department {DepartmentId = 3, DepartmentName = "IT"}
        //};



        //    persons = new List<Person>
        //{
        //    new Person
        //    {
        //        PersonId = 1, DepartmentId = 3, FirstName = "Ronald", LastName = "Rumple",
        //        Position = "Network Administrator", Address = "14 Malkie Avenue",  Holiday = 20,
        //        TaxCode = "LC455"
        //    },
        //    new Person
        //    {
        //        PersonId = 2, DepartmentId = 1, FirstName = "Brett", LastName = "Banner",
        //        Position = "Software Developer", Address = "4/L Long Terrace", PayratePH = 12.95, Holiday = 12.5,
        //        TaxCode = "LC455"
        //    },
        //    new Person
        //    {
        //        PersonId = 3, DepartmentId = 2, FirstName = "Alice", LastName = "Anderson",
        //        Position = "Accountant", Address = "56 Hemming Way", PayratePH = 10,  Holiday = 19.9,
        //        TaxCode = "LC455"
        //    }
        //};
        }

        private async void searchEmployee_Click(object sender, RoutedEventArgs e)
        {
            await new MessageDialog("Test").ShowAsync();

        }

        private void rota_Click(object sender, RoutedEventArgs e)
        {
            this.Frame.Navigate(typeof(Rota));
        }

        private void emailEmployee_Click(object sender, RoutedEventArgs e)
        {
            this.Frame.Navigate(typeof(email));
        }

        private void addEmployee_Click(object sender, RoutedEventArgs e)
        {
            this.Frame.Navigate(typeof(AddEmployee));
        }
    }
}

标签： c#xamluwp

解决方案

如何使 Person 类中的数据填充数据库并依次填充主页上的网格

您创建的 tableCommand1 字符串不完整，您需要像这样修改它：String tableCommand1 = "CREATE TABLE IF NOT EXISTS EmployeeTable (Employee_ID INTEGER PRIMARY KEY AUTOINCREMENT, First_Name NVARCHAR(20) NULL, Last_Name NVARCHAR(40) NULL, Address NVARCHAR(50) NULL, Position NVARCHAR(20) NULL, Pay_Rate DOUBLE NULL, Tax_Code NVARCHAR(10) NULL, Sex NVARCHAR(20), NI NVACHAR(10), Emergency_Details NVARCHAR(100))";

创建数据库的完整代码是：

public async static void database()
{
    await ApplicationData.Current.LocalFolder.CreateFileAsync("sqliteSample.db", CreationCollisionOption.OpenIfExists);
    string dbpath = Path.Combine(ApplicationData.Current.LocalFolder.Path, "sqliteSample.db");
    using (SqliteConnection db = new SqliteConnection($"Filename={dbpath}"))
    {
        //Creation of the database table
        db.Open();
        String tableCommand1 = "CREATE TABLE IF NOT EXISTS EmployeeTable (Employee_ID INTEGER PRIMARY KEY AUTOINCREMENT, First_Name NVARCHAR(20) NULL, Last_Name NVARCHAR(40) NULL, Address NVARCHAR(50) NULL, Position NVARCHAR(20) NULL, Pay_Rate DOUBLE NULL, Tax_Code NVARCHAR(10) NULL, Sex NVARCHAR(20), NI NVACHAR(10), Emergency_Details NVARCHAR(100))";

        SqliteCommand createTable = new SqliteCommand(tableCommand1, db);

        try
        {
            createTable.ExecuteReader();
        }
        catch (SqliteException ee){}
    }
}

当你要将 Person 的数据插入 DataBase 时，我以 first_name 为例：

private void InsertData(object sender, RoutedEventArgs e)
{
   string dbpath = Path.Combine(ApplicationData.Current.LocalFolder.Path, "sqliteSample.db");
    using (SqliteConnection db = new SqliteConnection($"Filename={dbpath}"))
    {
        db.Open();

        SqliteCommand insertCommand = new SqliteCommand();
        insertCommand.Connection = db;

        // Use parameterized query to prevent SQL injection attacks
        insertCommand.CommandText = "INSERT INTO EmployeeTable VALUES (NULL, @First_Name);";
        insertCommand.Parameters.AddWithValue("@First_Name", "Hello");

        insertCommand.ExecuteReader();
        db.Close();
    }
}

有关如何使用 sqlite 的更多详细信息，您可以参考此文档。

另外，当你想在 Grid 中显示新数据时，建议使用ObservableCollection类而不是 List，当你从这个类中插入或删除数据时，它会自动更新 UI。

ObservableCollection<Person> persons;

public MainPage()
{
    this.InitializeComponent();
    persons = new ObservableCollection<Person>();
    ......
}

如何从不同的页面添加到班级人员

您可以声明一个公共静态属性来表示 MainPage 实例，然后您可以直接调用公共方法来添加一个新的 Person 类。您可以将 NavigationCacheMode 设置为 Enabled，在这种情况下，当您返回 MainPage 时，数据将被缓存。例如：

主页.cs：

public MainPage()
{
    this.InitializeComponent();
    ......
    this.NavigationCacheMode = NavigationCacheMode.Enabled;

    Current = this;
}

public static MainPage Current;

public void addMethod(Person p) 
{
    persons.Add(p);
}

第二页.cs：

private void AddNewData(object sender, RoutedEventArgs e)
{
    //First add data to database like mainpage does
    MainPage.Current.addMethod(person);
}

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