移动应用程序如何与Azure后端Web应用程序“对话”

编程问答 2022-08-16

问题描述

我是一名初学者的移动应用程序开发人员，我不了解移动应用程序如何确切地通过azure后端Web应用程序请求某些SQL查询。

我在XamarinForms中有一个示例TodoItem移动应用程序，
与Azure SQL数据库连接的后端Web应用。

一个人如何与另一个人交谈以接收自定义查询或存储过程？ 2已经“连接”了，但是我不知道如何更改代码（c＃）以运行不同的查询/存储过程。

后端Web应用代码： 

    using System.Linq;
    using System.Threading.Tasks;
    using System.Web.Http;
    using System.Web.Http.Controllers;
    using System.Web.Http.OData;
    using Microsoft.Azure.Mobile.Server;
    using ZUMOAPPNAMEService.DataObjects;
    using ZUMOAPPNAMEService.Models;

    namespace ZUMOAPPNAMEService.Controllers
    {
    public class TodoItemController : TableController<TodoItem>
    {
        protected override void Initialize(HttpControllerContext controllerContext)
        {
            base.Initialize(controllerContext);
            ZUMOAPPNAMEContext context = new ZUMOAPPNAMEContext();
            DomainManager = new EntityDomainManager<TodoItem>(context,Request);
        }

        // GET tables/TodoItem
        public IQueryable<TodoItem> GetAllTodoItems()
        {
            return Query();
        }

        // GET tables/TodoItem
        public SingleResult<TodoItem> GetTodoItem(string id)
        {
            return Lookup(id);
        }

        // PATCH tables/TodoItem
        public Task<TodoItem> PatchTodoItem(string id,Delta<TodoItem> patch)
        {
            return UpdateAsync(id,patch);
        }

        // POST tables/TodoItem
        public async Task<IHttpActionResult> PostTodoItem(TodoItem item)
        {
            TodoItem current = await InsertAsync(item);
            return CreatedAtRoute("Tables",new { id = current.Id },current);
        }

        // DELETE tables/TodoItem
        public Task DeleteTodoItem(string id)
        {
            return DeleteAsync(id);
        }
    }
}

移动应用代码：

TodoList.xaml 

<?xml version="1.0" encoding="UTF-8"?>
<ContentPage    xmlns="http://xamarin.com/schemas/2014/forms" 
                xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" 
                x:Class="ZUMOAPPNAME.TodoList"
                Title="Azure Todo">
    
  <Grid RowSpacing="0">
    <Grid.RowDefinitions>
      <RowDefinition Height="Auto" />
      <RowDefinition Height="*" />
    </Grid.RowDefinitions>
    <ActivityIndicator Grid.RowSpan="2"
                       HorizontalOptions="Center"
                       VerticalOptions="Center"
                       IsVisible="False"
                       IsEnabled="True"
                       x:Name="syncIndicator"/>
    <StackLayout Grid.Row="0" BackgroundColor="Blue"  Padding="10,30,10,5">
      <Label TextColor="#555555" Text="Azure App Service" />
      <Grid>
        <Grid.ColumnDefinitions>
          <ColumnDefinition/>
          <ColumnDefinition Width="Auto"/>
        </Grid.ColumnDefinitions>
        <Entry x:Name="newItemName"
                  Placeholder="Item name" />
        <StackLayout x:Name="buttonsPanel" Grid.Column="1" Orientation="Horizontal" HorizontalOptions="StartAndExpand">
          <Button Text="+"
                  MinimumHeightRequest="30"
                  Clicked="OnAdd" />
        </StackLayout>
      </Grid>
    </StackLayout>
    <ListView x:Name="todoList"
                ItemSelected="OnSelected"
                IsPullToRefreshEnabled="true" Refreshing="OnRefresh"
                Grid.Row="1">
      <ListView.ItemTemplate>
        <DataTemplate>
          <ViewCell>
            <ViewCell.ContextActions>
              <MenuItem Clicked="OnComplete" Text="Complete" CommandParameter="{Binding .}"/>
            </ViewCell.ContextActions>
            <StackLayout HorizontalOptions="StartAndExpand" Orientation="Horizontal" Padding="15,5,0">
              <StackLayout Padding="5,0" VerticalOptions="StartAndExpand" Orientation="Vertical">
                <Label Text="{Binding Name}"  />
              </StackLayout>
            </StackLayout>
          </ViewCell>
        </DataTemplate>
      </ListView.ItemTemplate>
    </ListView>
  </Grid>
</ContentPage>

TodoList.xaml.cs 

using System;
using System.Threading.Tasks;
using Xamarin.Forms;

namespace ZUMOAPPNAME
{
    public partial class TodoList : ContentPage
    {
        TodoItemManager manager;

        public TodoList()
        {
            InitializeComponent();
            manager = TodoItemManager.DefaultManager;           
        }

        protected override async void OnAppearing()
        {
            base.OnAppearing();

            // Set syncItems to true in order to synchronize the data on startup when running in offline mode
            await RefreshItems(true,syncItems: true);
        }

        // Data methods
        async Task AddItem(TodoItem item)
        {
            await manager.SaveTaskAsync(item); //ADD ITEM
            todoList.ItemsSource = await manager.GetTodoItemsAsync(); // REFRESH
        }

        async Task CompleteItem(TodoItem item)
        {
            item.Done = true;
            await manager.SaveTaskAsync(item);
            todoList.ItemsSource = await manager.GetTodoItemsAsync();
        }

        public async void OnAdd(object sender,EventArgs e)
        {
            var todo = new TodoItem { Name = newItemName.Text };
            await AddItem(todo);

            newItemName.Text = string.Empty;
            newItemName.Unfocus();
        }

        // Event handlers
        public async void OnSelected(object sender,SelectedItemChangedEventArgs e)
        {
            var todo = e.SelectedItem as TodoItem;
            if (Device.RuntimePlatform != Device.iOS && todo != null)
            {
                // Not iOS - the swipe-to-delete is discoverable there
                if (Device.RuntimePlatform == Device.Android)
                {
                    await DisplayAlert(todo.Name,"Press-and-hold to complete task " + todo.Name,"Got it!");
                }
                else
                {
                    // Windows,not all platforms support the Context Actions yet
                    if (await DisplayAlert("Mark completed?","Do you wish to complete " + todo.Name + "?","Complete","Cancel"))
                    {
                        await CompleteItem(todo);
                    }
                }
            }

            // prevents background getting highlighted
            todoList.SelectedItem = null;
        }

        // http://developer.xamarin.com/guides/cross-platform/xamarin-forms/working-with/listview/#context
        public async void OnComplete(object sender,EventArgs e)
        {
            var mi = ((MenuItem)sender);
            var todo = mi.CommandParameter as TodoItem;
            await CompleteItem(todo);
        }

        // http://developer.xamarin.com/guides/cross-platform/xamarin-forms/working-with/listview/#pulltorefresh

        //PULL TO REFRESH
        public async void OnRefresh(object sender,EventArgs e)
        {
            var list = (ListView)sender;
            Exception error = null;
            try
            {
                await RefreshItems(false,true);
            }
            catch (Exception ex)
            {
                error = ex;
            }
            finally
            {
                list.EndRefresh();
            }

            if (error != null)
            {
                await DisplayAlert("Refresh Error","Couldn't refresh data (" + error.Message + ")","OK");
            }
        }
               

            //REFRESH ITEMS
        private async Task RefreshItems(bool showActivityIndicator,bool syncItems)
        {
            using (var scope = new ActivityIndicatorScope(syncIndicator,showActivityIndicator))
            {
                todoList.ItemsSource = await manager.GetTodoItemsAsync(syncItems);
            }
        }

        //ACTIVITY INDICATOR
        private class ActivityIndicatorScope : IDisposable
        {
            private bool showIndicator;
            private ActivityIndicator indicator;
            private Task indicatorDelay;

            public ActivityIndicatorScope(ActivityIndicator indicator,bool showIndicator)
            {
                this.indicator = indicator;
                this.showIndicator = showIndicator;

                if (showIndicator)
                {
                    indicatorDelay = Task.Delay(2000);
                    SetIndicatorActivity(true);
                }
                else
                {
                    indicatorDelay = Task.FromResult(0);
                }
            }

            private void SetIndicatorActivity(bool isActive)
            {
                this.indicator.IsVisible = isActive;
                this.indicator.IsRunning = isActive;
            }

            public void Dispose()
            {
                if (showIndicator)
                {
                    indicatorDelay.ContinueWith(t => SetIndicatorActivity(false),TaskScheduler.FromCurrentSynchronizationContext());
                }
            }
        }
    }
}

TodoItemManager.cs 

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Diagnostics;
using System.Threading.Tasks;
using Microsoft.WindowsAzure.MobileServices;
using Microsoft.WindowsAzure.MobileServices.Sync;

namespace ZUMOAPPNAME
{
    public partial class TodoItemManager
    {
        static TodoItemManager defaultInstance = new TodoItemManager();
        MobileServiceClient client;
        private IMobileServiceSyncTable<TodoItem> todoTable;

        private TodoItemManager()
        {
            this.client = new MobileServiceClient(Constants.ApplicationURL);

        }

        public static TodoItemManager DefaultManager
        {
            get
            {
                return defaultInstance;
            }
            private set
            {
                defaultInstance = value;
            }
        }

        public MobileServiceClient CurrentClient
        {
            get { return client; }
        }
        
        
        //Refresh Table list
        public async Task<ObservableCollection<TodoItem>> GetTodoItemsAsync(bool syncItems = false)
        {
            try
            {
                IEnumerable<TodoItem> items = await todoTable
                    .Where(todoItem => !todoItem.Done)
                    .ToEnumerableAsync();

                return new ObservableCollection<TodoItem>(items);
            }
            catch (MobileServiceInvalidOperationException msioe)
            {
                Debug.WriteLine("Invalid sync operation: {0}",new[] { msioe.Message });
            }
            catch (Exception e)
            {
                Debug.WriteLine("Sync error: {0}",new[] { e.Message });
            }
            return null;
        }

        //Add or Update if ID exists or not
        public async Task SaveTaskAsync(TodoItem item)
        {
            try
            {
                if (item.Id == null)
                {
                    await todoTable.InsertAsync(item);
                }
                else
                {
                    await todoTable.UpdateAsync(item);
                }
            }
            catch (Exception e)
            {
                Debug.WriteLine("Save error: {0}",new[] { e.Message });
            }
        }
    }
}

解决方法

暂无找到可以解决该程序问题的有效方法，小编努力寻找整理中！

如果你已经找到好的解决方法，欢迎将解决方案带上本链接一起发送给小编。

小编邮箱:dio#foxmail.com (将#修改为@）

azureazure-sql-databasebackendc#c#xamarin.forms

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