在AutoCompleteBox組件中集成搜索引擎的功能是十分常見的，這有助于我們更好地與Web進行交互。本文將為大家講述如何在在AutoCompleteBox組件中集成搜索引擎的搜索建議。

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實例：

說明：本實例用的搜索引擎是微軟的Bing(必應)

詳細的說明在代碼中給出。

WebServiceHelper.cs(業務輔助類)文件代碼：

using System;

using System.Collections.Generic;

using System.Linq;

using System.Globalization;

using System.Diagnostics.CodeAnalysis;

using System.Net;

using System.Windows.Browser;

using System.Windows.Controls;

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namespace SilverlightClient

{

?? public static class WebServiceHelper

??? {

??????? private const string LiveSuggestionsJsonUriFormat = "http://api.search.live.net/qson.aspx?query={0}";

??????? private const string LiveSearchUriFormat = "http://search.live.com/results.aspx?q={0}";

???????

??????? public static bool CanMakeHttpRequests

??????? {

??????????? get

?????????? ?{

??????????????? if (!HtmlPage.IsEnabled)

??????????????? {

??????????????????? return false;

??????????????? }

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??????????????? string scheme = HtmlPage.Document.DocumentUri.Scheme ?? string.Empty;

??????????????? return string.Compare(scheme, "http", StringComparison.OrdinalIgnoreCase) == 0;

??????????? }

??????? }

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??????? public static Uri CreateWebSearchUri(string searchText)

??????? {

??????????? return new Uri(string.Format(CultureInfo.InvariantCulture, LiveSearchUriFormat, HttpUtility.UrlEncode(searchText)));

??????? }

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??????? public static Uri CreateWebSearchSuggestionsUri(string searchText)

??????? {

??????????? return new Uri(string.Format(CultureInfo.InvariantCulture, LiveSuggestionsJsonUriFormat, HttpUtility.UrlEncode(searchText)));

??????? }

??? }

}

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MainPage.xaml文件代碼：

<UserControl

?? ?xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

?? ?xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

?? ?xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"

?? ?mc:Ignorable="d" xmlns:input="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Input" x:Class="SilverlightClient.MainPage"

?? ?d:DesignWidth="320" d:DesignHeight="240">

??? <Grid x:Name="LayoutRoot" Width="320" Height="240" Background="White">

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??????? <TextBlock Height="26" HorizontalAlignment="Left" Margin="8,8,0,0" VerticalAlignment="Top" Width="120" FontSize="16" Text="請輸入搜索詞：" TextWrapping="Wrap"/>

??????? <input:AutoCompleteBox x:Name="Search" FontSize="14" FilterMode="None" Height="26" Margin="8,55,112,0" VerticalAlignment="Top" Width="200"/>

??????? <Button x:Name="GoSearch" Height="26" HorizontalAlignment="Right" Margin="0,55,34,0" VerticalAlignment="Top" Width="74" Content="Search!" FontSize="13.333"/>

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??? </Grid>

</UserControl>

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MainPage.xaml.cs文件代碼：

using System;

using System.Collections.Generic;

using System.Diagnostics.CodeAnalysis;

using System.Json;

using System.Linq;

using System.Net;

using System.Windows;

using System.Windows.Browser;

using System.Windows.Controls;

using System.ComponentModel;

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namespace SilverlightClient

{

??? public partial class MainPage : UserControl

??? {

??????? public MainPage()

??????? {

??????????? InitializeComponent();

??????????? //注冊事件觸發處理

??????????? this.Loaded += new RoutedEventHandler(MainPage_Loaded);

??????? }

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??????? void MainPage_Loaded(object sender, RoutedEventArgs e)

??????? {

??????????? if (WebServiceHelper.CanMakeHttpRequests)//如果能做Http請求

??????????? {

??????????????? //注冊AutoCompleteBox組件的下拉框內容正在生成事件觸發處理

??????????????? Search.Populating += Search_Populating;

??????????????? //建立打開結果窗口的事件委托

??????????????? Action go = () => HtmlPage.Window.Navigate(WebServiceHelper.CreateWebSearchUri(Search.Text), "_blank");

??????????????? //注冊AutoCompleteBox組件的KeyUp事件觸發處理。當按下Enter鍵時，相當于提交

??????????????? Search.KeyUp += (s, args) =>

??????????????? {

??????????????????? if (args.Key == System.Windows.Input.Key.Enter)

??????????????????? {

??????????????????????? go();

??????????????????? }

??????????????? };

??????????????? //搜素按鈕的事件觸發處理

??????????????? GoSearch.Click += (s, args) => go();

??????????? }

??????? }

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??????? private void Search_Populating(object sender, PopulatingEventArgs e)

??????? {

??????????? AutoCompleteBox autoComplete = (AutoCompleteBox)sender;

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??????????? //等待結果

??????????? e.Cancel = true;

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??????????? //創建一個搜索建議請求

??????????? WebClient wc = new WebClient();

??????????? wc.DownloadStringCompleted += OnDownloadStringCompleted;

??????????? wc.DownloadStringAsync(WebServiceHelper.CreateWebSearchSuggestionsUri(autoComplete.SearchText), autoComplete);

??????? }

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??????? private void OnDownloadStringCompleted(object sender, DownloadStringCompletedEventArgs e)

??????? {

??????????? AutoCompleteBox autoComplete = e.UserState as AutoCompleteBox;

???????????

??????????? if (autoComplete != null && e.Error == null && !e.Cancelled && !string.IsNullOrEmpty(e.Result))//如果沒有出現異常情況的話

??????????? {

??????????????? List<string> data = new List<string>();

??????????????? try

??????????????? {

????????????? ??????JsonObject jso = ((JsonObject)JsonObject.Parse(e.Result))["SearchSuggestion"] as JsonObject;//創建Json對象

??????????????????? string originalSearchString = jso["Query"];//原始查詢字符串

??????????????????? if (originalSearchString == autoComplete.SearchText)

??????????????????? {

??????????????????????? foreach (JsonObject suggestion in (JsonArray)jso["Section"])

??????????????????????? {

??????????????????????????? data.Add(suggestion.Values.First());

??????????????????????? }

???????????????????????

??????? ????????????????autoComplete.ItemsSource = data;//填充AutoCompleteBox組件的數據源

??????????????????????? autoComplete.PopulateComplete();//結束AutoCompleteBox組件的下拉框內容生成

??????????????????? }

??????????????? }

??????????????? catch

??????????????? {

??????????????? }

??????????? }

??????? }

??? }

}

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最終效果圖：

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作者：Kinglee
文章出處：Kinglee’s Blog (http://www.cnblogs.com/Kinglee/)
版權聲明：本文的版權歸作者與博客園共有。轉載時須注明本文的詳細鏈接，否則作者將保留追究其法律責任。

轉載于:https://www.cnblogs.com/Kinglee/archive/2009/09/30/1577106.html

總結

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