Wpf 简明教程

WPF - Multimedia

WPF 应用程序使用 MediaElement 支持视频和音频。它允许您将音频和视频集成到应用程序中。MediaElement 类的工作方式类似于 Image 类。您只需将它指向媒体，它就会呈现媒体。主要区别在于它将是一个动态图像，但是，如果您将它指向仅包含音频且不包含视频（比如 MP3）的文件，它将播放该文件而不会在屏幕上显示任何内容。

WPF applications support video and audio using MediaElement. It allows you to integrate audio and video into an application. The MediaElement class works in a similar way as Image class. You just point it at the media and it renders it. The main difference is that it will be a moving image, but if you point it to the file that contains just audio and no video such as an MP3, it will play that without showing anything on the screen.

WPF 支持所有类型的视频/音频格式，具体取决于计算机配置。如果媒体文件在媒体播放器中播放，它在同一台计算机上的 WPF 中也可以播放。

WPF supports all types of video/audio format depending on the machine configuration. If a media file plays a Media Player, it will also work in WPF on the same machine.

Example

让我们用一个示例，来了解如何在应用程序中集成多媒体。

Let’s take an example to understand how to integrate multimedia in your application.

Create a new WPF project with the name WPFMultimedia.
The following XAML code creates a media element and three buttons, and initializes them with some properties.

<Window x:Class = "WPFMultimedia.MainWindow"
   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"
   xmlns:local = "clr-namespace:WPFMultimedia"
   mc:Ignorable = "d" Title = "MainWindow" Height = "350" Width = "604">

   <Grid>
      <StackPanel HorizontalAlignment = "Center" VerticalAlignment = "Center">
         <MediaElement Name = "myMedia" Source = "D:\MicrosoftMVA.mp4"
            LoadedBehavior = "Manual" Width = "591" Height = "274" />
         <StackPanel Orientation = "Horizontal" Margin = "0,10,0,0">
            <Button Content = "Play" Margin = "0,0,10,0" Padding = "5" Click = "mediaPlay" />
            <Button Content = "Pause" Margin = "0,0,10,0" Padding = "5" Click = "mediaPause" />
            <Button x:Name = "muteButt" Content = "Mute" Padding = "5" Click = "mediaMute" />
         </StackPanel>
      </StackPanel>
   </Grid>

</Window>

这是使用 C# 实现不同按钮的点击事件。

Here is the Click events implementation in C# for different buttons.

using System;
using System.Windows;

namespace WPFMultimedia {

   public partial class MainWindow : Window {

      public MainWindow() {
         InitializeComponent();
         myMedia.Volume = 100;
         myMedia.Play();
      }

      void mediaPlay(Object sender, EventArgs e) {
         myMedia.Play();
      }

      void mediaPause(Object sender, EventArgs e) {
         myMedia.Pause();
      }

      void mediaMute(Object sender, EventArgs e) {

         if (myMedia.Volume == 100) {
            myMedia.Volume = 0;
            muteButt.Content = "Listen";
         }
         else {
            myMedia.Volume = 100;
            muteButt.Content = "Mute";
         }
      }
   }
}

当您编译并执行以上代码时，它将生成以下窗口。你可以播放视频，并使用三个按钮控制播放。

When you compile and execute the above code, it will produce the following window. You can play the video and control its playback with the three buttons.

借助这些按钮，你可以暂停、静音和播放视频。

With the buttons you can pause, mute, and play the video.

Speech Synthesizer

WPF 具有将文本转换为语音的功能。此 API 包含在 System.Speech 命名空间中。 SpeechSynthesizer 类将文本转换为语音。

WPF has features to convert text to speech. This API is included in System.Speech namespace. SpeechSynthesizer class transforms text into spoken words.

Example

我们来看一个简单的示例。

Let’s have a look at a simple example.

Create a new WPF project with the name WPFTextToSpeech.
We will need System.Speech assembly to add as reference for SpeechSynthesizer class to work.
Right click on References and Select Add Reference.

Reference Manager dialog will open. Now check the System.Speech check box

Click the Ok button. You can see the System.Speech assembly in your References.

Now drag a button and a textbox into the design window from the toolbox.
The following XAML code creates a button and a textbox, and initializes them with some properties.

<Window x:Class = "WPFTextToSpeech.MainWindow"
   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"
   xmlns:local = "clr-namespace:WPFTextToSpeech"
   mc:Ignorable = "d" Title = "MainWindow" Height = "350" Width = "604">

   <Grid>
      <Button x:Name = "button" Content = "Speak"
         HorizontalAlignment = "Left" Margin = "218,176,0,0"
         VerticalAlignment = "Top" Width = "75"/>

      <TextBox x:Name = "textBox" HorizontalAlignment = "Left"
         Height = "23" Margin = "60,104,0,0" TextWrapping = "Wrap"
         VerticalAlignment = "Top" Width = "418"/>
   </Grid>

</Window>

Here is the simple implementation in C# which will convert the Text inside the textbox into spoken words.

using System.Speech.Synthesis;
using System.Windows;

namespace WPFTextToSpeech {
   /// <summary>
      /// Interaction logic for MainWindow.xaml
   /// </summary>

   public partial class MainWindow : Window {

      public MainWindow() {
         InitializeComponent();
      }

      private void button_Click(object sender, RoutedEventArgs e) {

         if (textBox.Text != "") {
            SpeechSynthesizer speechSynthesizer = new SpeechSynthesizer();
            speechSynthesizer.Speak(textBox.Text);
         }
         else {
            MessageBox.Show("Write some thing in the textbox!");
         }
      }
   }
}

当您编译并执行以上代码时，它将生成以下窗口。现在，在文本框中键入 Hello World，然后单击“说话”按钮。

When you compile and execute the above code, it will produce the following window. Now, type Hello World inside the textbox and click the Speak button.

它会产生“Hello World”的语音。如果您没有在文本框中键入任何内容，则会闪烁以下消息。

It will produce the sound "Hello World". If you don’t type anything in the textbox, then it will flash the following message.

我们建议您执行上述示例。

We recommend that you execute the above examples.