Andrey Ferzh's questions

假设我有某种 LiveCharts 图表。当我调整窗口大小时，我需要窗口的长度和宽度之间的比例为 1x1。

XAML 代码：

 <Grid Background="#f5f5f5">
     <Grid.ColumnDefinitions>
         <ColumnDefinition Width="5" />
         <ColumnDefinition />
         <ColumnDefinition Width="5" />
     </Grid.ColumnDefinitions>
     <Grid.RowDefinitions>
         <RowDefinition Height="5" />
         <RowDefinition />
         <RowDefinition Height="5" />
         <RowDefinition Height="40"/>
         <RowDefinition Height="5" />
     </Grid.RowDefinitions>

     <DockPanel Grid.Row="1" Grid.Column="1" Margin="5" HorizontalAlignment="Stretch" VerticalAlignment="Stretch">
         <StackPanel DockPanel.Dock="Top" Orientation="Horizontal">
             <Label Content="Номер сечения:"        Width="120" />
             <Label Content="{Binding SliderValue}" Width="100" />
         </StackPanel>

         <lvc:CartesianChart DockPanel.Dock="Top" DisableAnimations="True" LegendLocation="Top">
              <!-- Здесь какой-то график -->
         </lvc:CartesianChart>

     </DockPanel>

     <DockPanel Grid.Row="3" Grid.Column="1" HorizontalAlignment="Stretch" VerticalAlignment="Stretch">
         <StackPanel DockPanel.Dock="Left">
             <Slider Value="{Binding SliderValue, Mode=TwoWay}" Margin="5" SelectionStart="0" Minimum="0" Maximum="299" TickPlacement="BottomRight" TickFrequency="1" IsSnapToTickEnabled="True" IsSelectionRangeEnabled="True" />
         </StackPanel>
     </DockPanel>
 </Grid>

创建照片后，界面上显示照片，显示第一张照片，但创建新照片后，出现错误：

该进程无法访问文件“...tmp\Photo.jpeg”，因为该文件正在被另一个进程使用。

System.IO.IOException：进程无法访问文件“...tmp\Photo.jpeg”，因为它正在被另一个进程使用。在 System.IO.FileSystem.DeleteFile（字符串 fullPath） 在 System.IO.File.Delete（字符串路径） 在 PhotoMerge.ViewModel.MainViewModel.CreatePhoto（Int32 通道，相机相机） ...\ViewModel\MainViewModel.cs

模型：

public class Camera : INotifyPropertyChanged
{
   public event PropertyChangedEventHandler PropertyChanged;
   private string _address;
   private string _login;
   private string _password;
   private string _name;
   private string _path;
   private Uri? _imagePath;

   public string Address { get { return _address; } }
   public string Login { get { return _login; } }
   public string Password { get { return _password; } }
   public string Name { get { return _name; } }
   public string Path { get { return _path; } }

   public Uri? ImagePath
   {
      get { return _imagePath; }

      set
      {
         _imagePath = value;
         OnPropertyChanged("ImagePath");
      }
   }

   public Camera(string address, string login, string password, string name, string path)
   {
      _address = address;
      _login = login;
      _password = password;
      _name = name;
      _path = path; 
   }

   public void OnPropertyChanged([CallerMemberName] string prop = "")
   {
      if (PropertyChanged != null)
         PropertyChanged(this, new PropertyChangedEventArgs(prop));
   }
}

视图模型：

internal class MainViewModel : INotifyPropertyChanged
{
   private Camera camera;
   private ICommand createPhoto;

   public Camera Camera
   {
      get { return this.camera; }
   }

   public ICommand CreatePhoto
   {
      get { return this.createPhoto; }
   }

   public MainViewModel()
   {
      camera = new Camera("192.168.3.103", "admin", "1", "Photo", @"C:\tmp\");
      createPhoto = new DelegateCommand(parameter => CreateTestPhoto(1, camera));
   }

   private void CreateTestPhoto(int channel, Camera camera)
   {
      if (File.Exists(camera.Path + camera.Name + ".jpeg"))
         File.Delete(camera.Path + camera.Name + ".jpeg");

      if (HiWatch.Create(channel, camera.Login, camera.Password, camera.Path, camera.Name, 550))
      {
         BitmapImage bitmap = new BitmapImage();
         bitmap.BeginInit();
         bitmap.UriSource = new Uri(camera.Path + camera.Name + ".jpeg", UriKind.Absolute);
         bitmap.CacheOption = BitmapCacheOption.OnLoad;
         bitmap.CreateOptions = BitmapCreateOptions.IgnoreImageCache;
         bitmap.EndInit();

         camera.ImagePath = bitmap.UriSource;
      }
   }
}

XAML：

<Image Source="{Binding Camera.ImagePath}" DockPanel.Dock="Top" Margin="0" Width="Auto" Height="Auto" Stretch="Uniform" MinWidth="364" MinHeight="205" />

如何在UI中正确实现照片更新？

有一个 CreateMergePhoto() 方法可以合并两张 1920x1080px 照片并为其添加时间戳。在循环235张照片的过程中，不断出现错误：

  System.ArgumentException
  HResult=0x80070057
  Сообщение = Недопустимый параметр.
  Источник = System.Drawing
  Трассировка стека:
   at System.Drawing.Bitmap..ctor(Int32 width, Int32 height, PixelFormat format)
   at System.Drawing.Bitmap..ctor(Int32 width, Int32 height)
   at TestMergeCSharp.Program.CreateMergePhoto() in D:\...\Program.cs:line 55
   at TestMergeCSharp.Program.Main(String[] args) in D:\...\Program.cs:line 34

第一行指的是：

System.Drawing.Bitmap bm = new System.Drawing.Bitmap(width, height);

第二，到方法调用：

CreateMergePhoto();

程序代码：

public static void Main(string[] args)
{
    Console.WriteLine("Нажмите клавижу для запуска...");
    Console.ReadKey();

    while(CntMerge < 300)
    {
        Console.WriteLine("Изображение: " + CntMerge);
        CreateMergePhoto();
    }

    Console.ReadKey();
}

方法代码：

private static void CreateMergePhoto()
{
    CheckImages();

    string img1 = PathToSave1;
    string img2 = PathToSave2;

    System.Drawing.Bitmap bm1 = new System.Drawing.Bitmap(img1, true);
    System.Drawing.Bitmap bm2 = new System.Drawing.Bitmap(img2, true);

    int width  = bm1.Width > bm2.Width ? bm1.Width : bm2.Width;
    int height = bm1.Height + bm2.Height;

    System.Drawing.Bitmap bm = new System.Drawing.Bitmap(width, height);
    bm.SetResolution(72, 72);

    string currTime = DateTime.Now.ToString("dd/MM/yyyy HH:mm:ss");

    Graphics g = Graphics.FromImage(bm);
    g.FillRectangle(Brushes.Gray, 0, 0, width, height);
    g.DrawImage(bm1, 0, 0, bm1.Width, bm1.Height);
    g.DrawImage(bm2, 0, bm1.Height, bm2.Width, bm2.Height);

    g.FillRectangle(Brushes.Black, 0, height / 2, width, 56);
    g.DrawString(currTime, new Font("Arial", 52f), Brushes.White, 2, height / 2);

    bm.Save(PathToSave, System.Drawing.Imaging.ImageFormat.Jpeg);

    bm.Dispose();
    bm1.Dispose();
    bm2.Dispose();
}