将下拉选择器连接到数据库

Posted 2023-04-12

【中文标题】将下拉选择器连接到数据库

【英文标题】：Connecting dropdown picker to database

【发布时间】：2021-06-10 22:46:48

【问题描述】：

我正在做一个项目，我必须创建一个注册页面，并且在该页面中我必须有一个下拉选择器，以便用户可以选择他们来自的国家/地区。我正在按照我在 youtube 上找到的这个视频中的一些步骤进行操作：https://www.youtube.com/watch?v=E_0XDyy4ef8 和关于 udemy 的课程，但他们没有介绍如何创建后端代码以将其连接到数据库的步骤。如果有人可以帮助我，那就太好了！

xaml-

<Picker ItemDisplayBinding="Binding CountryName" 
                        x:Name="EntCountry" 
                        Title="Select Country" 
                        ItemsSource="Binding CountList" 
                        TextColor="White" 
                        TitleColor="White"/>

cs-

 private async void BtnSignUp_OnClicked(object sender, EventArgs e)
        
            var response = await ApiService.RegisterUser(EntName.Text, EntEmail.Text, EntPassword.Text, EntConfirmPassword.Text, EntDOB.Text, EntCountry);
                if (response)
            
                await DisplayAlert("Hello!", "Your account has been created", "Okay");
                await Navigation.PushModalAsync(new LoginPage()); //This will transition to another screen. 
            
            else
            
                await DisplayAlert("Hello!", "There is something wrong", "Okay");
            
        

Register.cs

class Register
    
        public string Name  get; set; 
        public string Email  get; set; 
        public string Password  get; set; 
        public string ConfirmPassword  get; set; 
        public string Country  get; set; 
        public string DOB  get; set; 
    

ApiService.cs-

public static async Task<bool> RegisterUser(string name, string email, string password, string confirmpassword, string dob, string country)
        
            var register = new Register()
            
                Name = name,
                Email = email,
                Password = password,
                ConfirmPassword = confirmpassword,
                Country = country,
                DOB = dob,

Country.cs-

public class Country
    
        public int CountryId  get; set; 
        public string CountryName  get; set; 
    

CountryViewModel.cs-

class CountryViewModel
    
        public IList<Country> CountList  get; set; 

        public CountryViewModel()
        
            try
            
                CountList = new ObservableCollection<Country>();
                CountList.Add(new Country  CountryId = 1, CountryName = "United States" );
                CountList.Add(new Country  CountryId = 2, CountryName = "Ecuador" );
                CountList.Add(new Country  CountryId = 3, CountryName = "Brazil" );
                CountList.Add(new Country  CountryId = 4, CountryName = "Argentina" );
                CountList.Add(new Country  CountryId = 5, CountryName = "Colombia" );
                CountList.Add(new Country  CountryId = 6, CountryName = "Peru" );
                CountList.Add(new Country  CountryId = 7, CountryName = "Chile" );
                CountList.Add(new Country  CountryId = 8, CountryName = "Venezuela" );
                CountList.Add(new Country  CountryId = 9, CountryName = "Bolivia" );
                CountList.Add(new Country  CountryId = 10, CountryName = "Uruguay" );
                CountList.Add(new Country  CountryId = 11, CountryName = "Paraguay" );
                CountList.Add(new Country  CountryId = 12, CountryName = "Mexico" );
            
            catch(Exception)
            

            
        
    

【问题讨论】：

那么也许你需要另一个关于如何从 c# 查询数据库的视频 - 对于 SO 问题来说有点宽泛

【参考方案1】：

您是否为 VM 使用了 BindingContext？看看this。作为建议，如果您使用 VM，请尝试将单击按钮的代码放入其中。