wp7中出现内存不足异常

本文关键字：内存不足 异常 wp7 | 更新日期: 2023-09-27 18:20:41

我想制作一个应用程序，使用相机捕捉图像并将其存储在手机的独立存储中。无论如何，我能够在每次运行中存储7个图像（即每次激活模拟器时），对于我捕获和保存的8个图像，我会出现内存不足的异常。如果我必须在隔离存储中存储更多的映像，我必须停止调试并重新启动调试。我是wp7开发的新手。我正在使用模拟器进行调试。请帮助

    Stream doc_photo;
    List<document> doc_list = new List<document>();
    document newDoc = new document();
    public Page2()
    {
        InitializeComponent();
    }

    private void captureDocumentImage(object sender, RoutedEventArgs e)
    {
        ShowCameraCaptureTask();
    }
    private void ShowCameraCaptureTask()
    {
        CameraCaptureTask photoCameraCapture = new CameraCaptureTask();
        photoCameraCapture = new CameraCaptureTask();
        photoCameraCapture.Completed += new EventHandler<PhotoResult>photoCameraCapture_Completed);
        photoCameraCapture.Show();
    }
    void photoCameraCapture_Completed(object sender, PhotoResult e)
    {
        if (e.TaskResult == TaskResult.OK)
        {
            capturedImage.Source = PictureDecoder.DecodeJpeg(e.ChosenPhoto);
            doc_photo = e.ChosenPhoto;
        }
    }
    private void SaveToIsolatedStorage(Stream imageStream, string fileName)
    {
        using (IsolatedStorageFile myIsolatedStorage = IsolatedStorageFile.GetUserStoreForApplication())
        {
            if (myIsolatedStorage.FileExists(fileName))
            {
                myIsolatedStorage.DeleteFile(fileName);
            }
            IsolatedStorageFileStream fileStream = myIsolatedStorage.CreateFile(fileName);
            BitmapImage bitmap = new BitmapImage();
            bitmap.SetSource(imageStream);
            try
            {
                WriteableBitmap wb = new WriteableBitmap(bitmap);
                wb.SaveJpeg(fileStream, wb.PixelWidth, wb.PixelHeight, 0, 85);
                fileStream.Close();
            }
            catch (OutOfMemoryException e1)
            {
                MessageBox.Show("memory exceeded");
            }
        }
    }
    private void save_buttonclicked(object sender, RoutedEventArgs e)
    {
        if (namebox.Text != "" && doc_photo!=null)
        {
            newDoc.doc_name = namebox.Text;
            IsolatedStorageFile myIsolatedStorage = IsolatedStorageFile.GetUserStoreForApplication();
            if(!myIsolatedStorage.DirectoryExists(App.current_panorama_page))
            {
               myIsolatedStorage.CreateDirectory(App.current_panorama_page);
            }
            newDoc.photo = App.current_panorama_page + "/" + namebox.Text + ".jpg";//
            SaveToIsolatedStorage(doc_photo, newDoc.photo);
            doc_list.Add(newDoc);
            NavigationService.Navigate(new Uri("/MainPage.xaml", UriKind.Relative));
        }
        else
        {
            if (namebox.Text == "")
            {
                MessageBox.Show("Enter the name");
            }
            else if (doc_photo == null) 
            {
                MessageBox.Show("Capture an Image");
            }
        }
    }

wp7中出现内存不足异常

您将位图保存到"doc_list"，而不仅仅是URL，因此手机将在内存中存储您捕获的每个图像。您可能应该选择一种解决方案，在该解决方案中，使用常规图像控件和"isostore://"URL在UI中引用图像。

编辑：

在下面的示例中，我使用ObservableCollection来存储IsoImageWrappers。后一个类通过用构造函数中给定的URI实例化一个隔离的文件流来处理到隔离存储的连接。

ObservableCollection将在添加新图像时通知WP7框架。存储图像几乎就像您最初的建议一样。

列表框绑定为：

 <ListBox Grid.Row="0" Height="495" Margin="0" Name="listBox1" Width="460" >
    <ListBox.ItemTemplate>
       <DataTemplate>
          <Image Source="{Binding Source}" Width="Auto" />
       </DataTemplate>
    </ListBox.ItemTemplate>
 </ListBox>

以及助手类的丑陋内联代码等：

using System;
using System.Collections.ObjectModel;
using System.IO;
using System.IO.IsolatedStorage;
using System.Windows;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using Microsoft.Phone.Controls;
using Microsoft.Phone.Tasks;
namespace WP7Photo
{
    public partial class MainPage : PhoneApplicationPage
    {
        public class IsoImageWrapper
        {
            public string Uri { get; set; }
            public ImageSource Source
            {
                get
                {
                    IsolatedStorageFile isostore = IsolatedStorageFile.GetUserStoreForApplication();
                    var bmi = new BitmapImage();
                    bmi.SetSource(isostore.OpenFile(Uri, FileMode.Open, FileAccess.Read));
                    return bmi;
                }
            }
        }
        public ObservableCollection<IsoImageWrapper> Images { get; set; }
        // Constructor
        public MainPage()
        {
            InitializeComponent();
            Images = new ObservableCollection<IsoImageWrapper>();
            listBox1.ItemsSource = Images;
        }
        private void Button1Click(object sender, RoutedEventArgs e)
        {
            var cameraTask = new CameraCaptureTask();
            cameraTask.Completed += new EventHandler<PhotoResult>(cameraTask_Completed);
            cameraTask.Show();
        }
        void cameraTask_Completed(object sender, PhotoResult e)
        {
            if (e.TaskResult != TaskResult.OK)
            {
                return;
            }
            StorePhoto(e);
        }
        private void StorePhoto(PhotoResult photo)
        {
            IsolatedStorageFile isostore = IsolatedStorageFile.GetUserStoreForApplication();
            if (!isostore.DirectoryExists("photos"))
            {
                isostore.CreateDirectory("photos");
            }
            var filename = "photos/"  + System.IO.Path.GetFileName(photo.OriginalFileName);
            if (isostore.FileExists(filename)) { isostore.DeleteFile(filename);}
            using (var isoStream = isostore.CreateFile(filename))
            {
                photo.ChosenPhoto.CopyTo(isoStream);
            }
            Images.Add(new IsoImageWrapper {Uri = filename});
        }
    }
}
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