[Discovery]初識Windows通用應用（UWP App） - HelloWorld

初識Windows通用應用（UWP App） - HelloWorld

  自從Windows 10第一預覽版泄露以來，對UWP一直頗感神祕，今天閒下來有空搞了搞。

  項目結構：

創建項目：

首先創建一個空白的Windows通用應用。

然後再解決方案中會生成一大堆的文件，其中要注意一下MainPage.xml，它是用來定義界面的，其根元素爲Page，自定義的界面代碼在Grid元素中編寫。

詳細轉到此網址：Create a "Hello, world" app (XAML)

廢話不多說，貼代碼：

MainPage.xaml文件：

<Page
    x:Class="UWPDemo1.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:UWPDemo1"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d">

    <Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">

        <VisualStateManager.VisualStateGroups>
            <VisualStateGroup>

                <!--表示大於641 pixel顯示的樣式-->
                <VisualState x:Name="wideState">
                    <VisualState.StateTriggers>
                        <!--規定最小的寬度爲641 pixel-->
                        <AdaptiveTrigger MinWindowWidth="641"/>
                    </VisualState.StateTriggers>

                    <VisualState.Setters>
                        <Setter Target="submitBtn.HorizontalAlignment" Value="Right" />
                        <Setter Target="submitBtn.Margin" Value="300,50,100,0" />
                    </VisualState.Setters>
                </VisualState>

                <!--表示在0 pixel到641 pixel之間顯示的樣式-->
                <VisualState x:Name="narrowState">
                    <VisualState.StateTriggers>
                        <!--規定最小寬度爲0 pixel，因爲上面已定義一個比當前寬度大的pixel，所以會在這個區間內（0~641）顯示-->
                        <AdaptiveTrigger MinWindowWidth="0" />
                    </VisualState.StateTriggers>
                    
                    <!--設置元素的位置和屬性-->
                    <VisualState.Setters>
                        <!--定位contentArea-->
                        <Setter Target="contentArea.Orientation" Value="Vertical" />
                        <!--設定按鈕的外邊距（Margin：左、上、右、下）-->
                        <Setter Target="submitBtn.Margin" Value="150,50,150,0" />

                        <!--設定文本框的外邊距（Margin：左、上、右、下）-->
                        <Setter Target="inputUserName.HorizontalAlignment" Value="Left" />

                        <Setter Target="resultArea.Margin" Value="0,0,0,80" />
                    </VisualState.Setters>
                </VisualState>
            </VisualStateGroup>
        </VisualStateManager.VisualStateGroups>
        
        <StackPanel Margin="8,32,0,0">
            <TextBlock Text="Hello World" Margin="0,0,0,40" FontSize="29.333" />
            <TextBlock Text="你叫什麼名字？"/>
            <StackPanel Margin="0,20,0,20" x:Name="contentArea">
                <TextBox x:Name="inputUserName" Margin="10,0" HorizontalAlignment="Center" Width="228" />
                <Button x:Name="submitBtn" Content="確認" Click="submitBtn_Click" HorizontalAlignment="Stretch" Margin="125,100,125,0" />
            </StackPanel>
            <TextBlock x:Name="resultArea"/>
        </StackPanel>
    </Grid>
</Page>

對於不同窗口的自適應縮放，官方文檔說的很清楚，也是UWP App的核心之一，通過添加一個VisualStateManager來規定當窗口的Size處於哪一範圍內時應用什麼樣式，樣式通過其內VisualState的Setter元素來設定。

MainPage.xaml.cs文件：

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices.WindowsRuntime;
using UWPDemo1.DDL;
using Windows.Foundation;
using Windows.Foundation.Collections;
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;

//“空白頁”項模板在 http://go.microsoft.com/fwlink/?LinkId=402352&clcid=0x409 上有介紹

namespace UWPDemo1
{
    /// <summary>
    /// 可用於自身或導航至 Frame 內部的空白頁。
    /// </summary>
    public sealed partial class MainPage : Page
    {
        public MainPage()
        {
            this.InitializeComponent();
        }

        private async void submitBtn_Click(object sender, RoutedEventArgs e)
        {
            //創建一個消息框
            var dialog = new ContentDialog(){ Title="消息提示",Content="您的姓名是："+this.inputUserName.Text+"。",PrimaryButtonText="確定",SecondaryButtonText="取消",FullSizeDesired=false};

            this.resultArea.Text = "您的姓名是"+this.inputUserName.Text + "。";

            dialog.PrimaryButtonClick += Dialog_PrimaryButtonClick;

            dialog.SecondaryButtonClick += Dialog_SecondaryButtonClick;

            //異步等待用戶操作的方式顯示信息框
            await dialog.ShowAsync();
        }

        private BusinessService service = new BusinessService();

        private void Dialog_SecondaryButtonClick(ContentDialog sender, ContentDialogButtonClickEventArgs args)
        {
            this.resultArea.Text = service.CheckResult(this.inputUserName.Text);
        }

        private  void Dialog_PrimaryButtonClick(ContentDialog sender, ContentDialogButtonClickEventArgs args)
        {
            this.resultArea.Text = service.CheckResult(this.inputUserName.Text);
        }
    }
}

BusinessService類：

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

namespace UWPDemo1.DDL
{
    public class BusinessService
    {
        public String CheckResult(String name)
        {
            if (name.Length == 0)
            {
                return "非常抱歉！您的姓名在嘗試確認操作時失敗！\n您的姓名確認失敗。";
            }
            else
            {
                SQLiteConnection _connection = new SQLiteConnection(DB_NAME);

                using (var statement = _connection.Prepare(SQL_CREATE_TABLE))
                {
                    statement.Step();
                }

                using (var statement = _connection.Prepare(SQL_INSERT))
                {
                    statement.Bind(1, name);
                    statement.Bind(2, "我叫" + name);
                    statement.Step();
                }

                String content = string.Empty;

                using (var statement = _connection.Prepare(SQL_QUERY_VALUE))
                {
                    statement.Bind(1,"Steve Jrong");
                    SQLiteResult result = statement.Step();
                    if (SQLiteResult.ROW == result)
                    {
                        content = statement[0] as String;
                    }
                }

                return "恭喜！您的姓名已確認！\n您的姓名爲：" + name + "。\n內容爲："+content;
            }
        }

        private static String DB_NAME = "SQLiteSample.db";
        private static String TABLE_NAME = "SampleTable";
        private static String SQL_CREATE_TABLE = "CREATE TABLE IF NOT EXISTS " + TABLE_NAME + " (Key TEXT,Value TEXT);";
        private static String SQL_QUERY_VALUE = "SELECT Value FROM " + TABLE_NAME + " WHERE Key = (?);";
        private static String SQL_INSERT = "INSERT INTO " + TABLE_NAME + " VALUES(?,?);";
        private static String SQL_UPDATE = "UPDATE " + TABLE_NAME + " SET Value = ? WHERE Key = ?";
        private static String SQL_DELETE = "DELETE FROM " + TABLE_NAME + " WHERE Key = ?";
    }
}

這裏還使用了SQLite嵌入式數據庫進行增加和查詢操作，具體引用步驟如下：

下載對應平臺的SQLite組件，這裏因爲是UWP Platform，所以文件是sqlite-uap-3090200.vsix；

下載完成後雙擊安裝，之後重啓Visual Studio；

在項目中引用SQLite組件；

項目右鍵點擊“管理NuGet程序包”，在彈出的窗口中搜索“SQLitePCL”並安裝，此時項目中會多出SQLitePCL的引用。

此時SQLite的環境就配置完畢了。