nullReferenceException当我尝试播放音效？

Question

我正在与音效声卡和我越来越：

"A first chance exception of type 'System.NullReferenceException'" 
    when building after 'UI Task' (Managed): 
    Loaded 'Microsoft.Xna.Framework.dll' 

我确实有它的工作，但改变（覆盖了以前的版本）后，我已经收到此错误和我卡。 Java是我的第一语言，使用C＃我是初学者。我花了无数小时寻找解决方案。

nullReferenceException来自loadsound（），我想！我在名为resources和build action的文件夹中有声音文件（.wav）：resources和copy to output：不要复制（尝试所有选项）。此外，在参考文献中提到了Microsoft.Xna.Framework

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Net; 
using System.Windows; 
using System.Windows.Controls; 
using System.Windows.Documents; 
using System.Windows.Input; 
using System.Windows.Media; 
using System.Windows.Media.Animation; 
using System.Windows.Resources; 
using System.Windows.Shapes; 
using Microsoft.Phone.Controls; 
using Microsoft.Xna.Framework; 
using Microsoft.Xna.Framework.Audio; 
using Microsoft.Xna.Framework.Media; 

namespace Craggy_Island 
{ 
    public partial class MainPage : PhoneApplicationPage 
    { 
     // The Resources to play 
     private SoundEffect drink;//(plus 23 more effects) 

     // Flag that indicates if we need to resume Zune playback upon exiting. 
     bool resumeMediaPlayerAfterDone = false; 

     // Constructor 
     public MainPage() 
     { 
      InitializeComponent(); 

      // Timer to simulate the XNA game loop (SoundEffect class is from the XNA Framework) 
      GameTimer gameTimer = new GameTimer(); 
      gameTimer.UpdateInterval = TimeSpan.FromMilliseconds(33); 

      // Call FrameworkDispatcher.Update to update the XNA Framework internals. 
      gameTimer.Update += delegate { try { FrameworkDispatcher.Update(); } catch { } }; 

      // Start the GameTimer running. 
      gameTimer.Start(); 

      // Prime the pump or we'll get an exception. 
      FrameworkDispatcher.Update(); 

      //LoadSound("Resources/drink.wav", out drink); 
      // Create and load SoundEffect objects. 
      LoadSound("Resources/drink.wav", out drink); 

     } 

     private void LoadSound(String SoundFilePath, out SoundEffect Sound) 
     { 
      // For error checking, assume we'll fail to load the file. 
      Sound = null; 

      try 
      { 
       // Holds informations about a file stream. 
       StreamResourceInfo SoundFileInfo = App.GetResourceStream(new Uri(SoundFilePath, UriKind.Relative)); 

       // Create the SoundEffect from the Stream 
       Sound = SoundEffect.FromStream(SoundFileInfo.Stream); 
      } 
      catch (NullReferenceException) 
      { 
       // Display an error message 
       MessageBox.Show("Couldn't load sound " + SoundFilePath); 
      } 
     } 



     private void button_Click(object sender, RoutedEventArgs e) 
     { 
      Button Current = sender as Button; 

      try 
      { 
       if (Current.Equals(button1)) 
        drink.Play();//(other buttons here for other sound effects) 



      } 
      catch (NullReferenceException) 
      { 
       MessageBox.Show("Can't play, sound file problem."); 
      } 

     } 
     #region Zune Pause/Resume 

     private void ZunePause() 
     { 
      // Please see the MainPage() constructor above where the GameTimer object is created. 
      // This enables the use of the XNA framework MediaPlayer class by pumping the XNA FrameworkDispatcher. 

      // Pause the Zune player if it is already playing music. 
      if (!MediaPlayer.GameHasControl) 
      { 
       MediaPlayer.Pause(); 
       resumeMediaPlayerAfterDone = true; 
      } 
     } 

     private void ZuneResume() 
     { 
      // If Zune was playing music, resume playback 
      if (resumeMediaPlayerAfterDone) 
      { 
       MediaPlayer.Resume(); 
      } 
     } 

     #endregion Zune Pause/Resume 

    } 
} 

Answer 1

废除我的原始答案，除非您使用XNA在Windows/Xbox上进行游戏开发。 （原来的海报正在使用它的Zune的。）

关于WAV文件：

第一个问题是，你需要设置Copy to Output Directory到Copy if newer。 （您可以使用Always，但这是不必要的。）

第二个问题是它的类型需要设置为Content。

Answer 2

您正在采取艰难的做法。查看ContentManager（可从Game实例中作为this.Content访问）。您可以使用Content.Load<T>(string)来访问您的音频文件，但您需要将音频文件放入内容项目中。不要更改其类型：将其保留为默认值。即使它不是一种资源，放弃它。它将被编译成不同的格式。另外，省略传递给Content.Load<>的参数的文件扩展名。

Answer 3

你开始你正在加载的声音在比赛之前我几乎同样的问题

gameTimer.Start(); 

FrameworkDispatcher.Update(); 

LoadSound("Resources/drink.wav", out drink); 

Answer 4

。最后我得到了它无意中如下：

StreamResourceInfo streaminfo = Application.GetResourceStream(new Uri("project_name;component/folder_name/Sound3.wav", UriKind.RelativeOrAbsolute)); 
SoundEffect effect1 = SoundEffect.FromStream(streaminfo.Stream); 
effect1.Play(); 

AND： 属性“建设行动” .wav文件必须设置好的，以“资源”和Porperty“复制到输出目录”应设置好的来“复制如果更新“

顺便说一句，我正在使用Silverlight5。