设置 XAML 窗口始终位于顶部（但没有 TopMost 属性）

Question

我正在开发一个基于 OptiTrack SDK（来自 NaturalPoint）的应用程序。我需要将应用程序窗口运行为“Always on Top”。该窗口是用 XAML 设计的，并在“CameraView”类中进行控制，但它似乎不包含“TopMost”属性或等效属性。附件是“CameraView.xaml.cs”的代码和“CameraView.xaml”的代码，它们是 OptiTrack SDK (NaturalPoint) 的一部分，称为“Single_Camera_CSharp_.NET_3.0”。

人们可能期望 CameraView 类包含属性或成员来设置窗口在屏幕上的位置或将其设置为 TopMost，但就搜索而言，我什么也没找到。我想知道我应该做什么。

谢谢你， 布莱恩

================

“CameraView.xaml.cs”

using System;
using System.IO;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Navigation;
using System.Drawing.Imaging;
using System.Drawing.Drawing2D;
using System.Windows.Threading;

namespace TestProject
{
public partial class CameraView
{
private const int NP_OPTION_OBJECT_COLOR_OPTION = 3;
private const int NP_OPTION_VIDEO_TYPE = 48;
private const int NP_OPTION_NUMERIC_DISPLAY_ON = 71;
private const int NP_OPTION_NUMERIC_DISPLAY_OFF = 72;
private const int NP_OPTION_FETCH_RLE = 73;
private const int NP_OPTION_FETCH_GRAYSCALE = 74;
private const int NP_OPTION_FRAME_DECIMATION = 52;
private const int NP_OPTION_INTENSITY = 50;
private const int NP_OPTION_SEND_EMPTY_FRAMES = 41;
private const int NP_OPTION_THRESHOLD = 5;
private const int NP_OPTION_EXPOSURE = 46;
private const int NP_OPTION_SEND_FRAME_MASK = 73;
private const int NP_OPTION_TEXT_OVERLAY_OPTION = 74;
// public delegate void OnCameraViewCreate(CameraView camera);
// public static OnCameraViewCreate onCameraViewCreate;
private System.Drawing.Bitmap raw = new System.Drawing.Bitmap(353, 288, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
private int mFrameCounter;
private int mDisplayCounter;
private DispatcherTimer timer1 = new DispatcherTimer();
private bool mVideoFrameAvailable = false;
private int mNumeric = -1;
private bool mGreyscale = false;
private bool mOverlay = true;
public CameraView()
{
this.InitializeComponent();

timer1.Interval = new TimeSpan(0, 0, 0, 0, 10);
timer1.Tick += new EventHandler(timer1_Tick);
}

public int Numeric
{
get { return mNumeric; }
set
{
mNumeric = value % 100;
if (mNumeric >= 0)
{
if (Camera != null)
Camera.SetOption(NP_OPTION_NUMERIC_DISPLAY_ON, value % 100);
}
}
}

private bool CameraRunning = false;
private OptiTrack.NPCamera mCamera;
public OptiTrack.NPCamera Camera
{
get { return mCamera; }
set
{
if (mCamera == value) return; //== Don't do anything if you're assigning the same camera ==

if (mCamera != null)
{
//== Shut the selected camera down ==<<

if (CameraRunning)
{
CameraRunning = false;
mCamera.Stop();
mCamera.FrameAvailable -= FrameAvailable;
}
}

mCamera = value;

if (mCamera == null)
{
mNumeric = -1;
}
else
{
serialLabel.Content = "Camera "+mCamera.SerialNumber.ToString(); //mNumeric.ToString();
}
}
}

private void FrameAvailable(OptiTrack.NPCamera Camera)
{
mFrameCounter++;

try
{
OptiTrack.NPCameraFrame frame = Camera.GetFrame(0);
int id = frame.Id;
if (CameraRunning)
{
GetFrameData(Camera, frame);
}

frame.Free();
}
catch (Exception)
{
int r = 0;
r++;
}
}
private void GetFrameData(OptiTrack.NPCamera camera, OptiTrack.NPCameraFrame frame)
{
BitmapData bmData = raw.LockBits(new System.Drawing.Rectangle(0, 0, raw.Width, raw.Height),
ImageLockMode.ReadWrite, System.Drawing.Imaging.PixelFormat.Format32bppArgb);

int stride = bmData.Stride;
System.IntPtr bufferPtr = bmData.Scan0;
unsafe
{
byte* buffer = (byte*)(void*)bufferPtr;
camera.GetFrameImage(frame, bmData.Width, bmData.Height, bmData.Stride, 32, ref buffer[0]);
}
raw.UnlockBits(bmData);
mVideoFrameAvailable = true;
}

private void timer1_Tick(object sender, EventArgs e)
{
if (CameraRunning && mVideoFrameAvailable)
{
mVideoFrameAvailable = false;
cameraImage.Source = Img(raw);
mDisplayCounter++;
}
}

private System.Windows.Media.ImageSource Img(System.Drawing.Bitmap img)
{
System.Drawing.Imaging.BitmapData bmData = img.LockBits(new System.Drawing.Rectangle(0, 0, img.Width, img.Height),
System.Drawing.Imaging.ImageLockMode.ReadWrite, System.Drawing.Imaging.PixelFormat.Format32bppPArgb);

System.Windows.Media.Imaging.BitmapSource bitmap = System.Windows.Media.Imaging.BitmapSource.Create(
img.Width, img.Height, 96, 96, PixelFormats.Bgra32,
System.Windows.Media.Imaging.BitmapPalettes.WebPalette,
bmData.Scan0, bmData.Stride * bmData.Height, bmData.Stride);
img.UnlockBits(bmData);

return bitmap;
}
private void startStopButton_Click(object sender, RoutedEventArgs e)
{
if (CameraRunning)
StopCamera();
else
StartCamera();
}

public void StartCamera()
{
if (Camera != null)
{
mFrameCounter = 0;
mDisplayCounter = 0;

Camera.FrameAvailable += FrameAvailable;

Camera.SetOption(NP_OPTION_VIDEO_TYPE, 0);
Camera.SetOption(NP_OPTION_FRAME_DECIMATION, 1);

Camera.SetOption(NP_OPTION_INTENSITY, 0);
Camera.SetOption(NP_OPTION_EXPOSURE, 10);
Camera.SetOption(NP_OPTION_THRESHOLD, 50);
Camera.SetOption(NP_OPTION_OBJECT_COLOR_OPTION, 0);
SetOverlayOption();
SetGreyscaleOption();

timer1.Start();
Camera.Start();
CameraRunning = true;
this.Numeric = mNumeric;

startStopButton.Content = "Stop Camera";
}
}
private void SetGreyscaleOption()
{
if(mGreyscale)
Camera.SetOption(NP_OPTION_VIDEO_TYPE, 1);
else
Camera.SetOption(NP_OPTION_VIDEO_TYPE, 0);
}
private void SetOverlayOption()
{
if(mOverlay)
Camera.SetOption(NP_OPTION_TEXT_OVERLAY_OPTION, 255);
else
Camera.SetOption(NP_OPTION_TEXT_OVERLAY_OPTION, 0);
}

public void StopCamera()
{
if (Camera != null)
{
Camera.Stop();
timer1.Stop();
CameraRunning = false;
Camera.FrameAvailable -= FrameAvailable;
Camera.SetOption(NP_OPTION_NUMERIC_DISPLAY_OFF, 0);
startStopButton.Content = "Start Camera";
}
}

private void greyscaleButton_Click(object sender, RoutedEventArgs e)
{
if(mGreyscale)
mGreyscale = false;
else
mGreyscale = true;
SetGreyscaleOption();
}

private void OverlayButton_Click(object sender, RoutedEventArgs e)
{
if(mOverlay)
mOverlay = false;
else
mOverlay = true;
SetOverlayOption();
}

private void exposureSlider_ValueChanged(object sender, RoutedEventArgs e)
{
if (mCamera!=null)
{
mCamera.SetOption(NP_OPTION_EXPOSURE, (int) this.exposureSlider.Value);
}
}

private void thresholdSlider_ValueChanged(object sender, RoutedEventArgs e)
{
if (mCamera != null)
{
mCamera.SetOption(NP_OPTION_THRESHOLD, (int)this.thresholdSlider.Value);
}
}

private void optionsButton_Click(object sender, RoutedEventArgs e)
{
if (!propertyPanel.IsVisible)
propertyPanel.Visibility = Visibility.Visible;
else
propertyPanel.Visibility = Visibility.Collapsed;
}
}
}

================

“CameraView.xaml”

<UserControl
 xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
 xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
 x:Class="TestProject.CameraView"
 x:Name="CameraView1"
 Width="Auto" Height="Auto"
 xmlns:d="http://schemas.microsoft.com/expression/blend/2006" 
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
    mc:Ignorable="d"
 >

 <Grid x:Name="LayoutRoot" Width="Auto" Height="Auto">
  <Grid.Background>
   <x:Null/>
  </Grid.Background>
  <Grid.ColumnDefinitions>
   <ColumnDefinition Width="*"/>
   <ColumnDefinition Width="113.904"/>
  </Grid.ColumnDefinitions>
  <Grid.RowDefinitions>
   <RowDefinition Height="26.667"/>
   <RowDefinition Height="*"/>
  </Grid.RowDefinitions>
  <Grid Margin="0,0,0,0" Grid.ColumnSpan="2">
   <Rectangle RadiusX="1.25" RadiusY="1.25" Margin="0,0,0,0" VerticalAlignment="Stretch">
    <Rectangle.Fill>
     <LinearGradientBrush EndPoint="0.492,0.149" StartPoint="0.492,0.843">
      <GradientStop Color="#FF000000" Offset="0"/>
      <GradientStop Color="#FF23283F" Offset="1"/>
     </LinearGradientBrush>
    </Rectangle.Fill>
    <Rectangle.Stroke>
     <LinearGradientBrush EndPoint="0.291,-4.231" StartPoint="1.668,18.025">
      <GradientStop Color="#FF000000" Offset="0"/>
      <GradientStop Color="#FFFFFFFF" Offset="1"/>
     </LinearGradientBrush>
    </Rectangle.Stroke>
   </Rectangle>
   <Rectangle RadiusX="3.333" RadiusY="3.333" Opacity="0.13" Margin="0,0,0,13">
    <Rectangle.Fill>
     <SolidColorBrush Color="#FFFFFFFF"/>
    </Rectangle.Fill>
    <Rectangle.Stroke>
     <x:Null/>
    </Rectangle.Stroke>
   </Rectangle>
  </Grid>
  <Image Margin="0,0,0,0" x:Name="cameraImage" Grid.ColumnSpan="2" Grid.Row="1"/>
  <Label x:Name="serialLabel" FontSize="10" FontWeight="Bold" Foreground="#FFDEDADA" Content="Camera 10024" HorizontalAlignment="Right" Margin="0,0,4,0" VerticalAlignment="Top" Grid.Column="1">
   <Label.BitmapEffect>
    <OuterGlowBitmapEffect GlowColor="#FF000000" GlowSize="4" Opacity="0.7"/>
   </Label.BitmapEffect>
  </Label>
  <WrapPanel Margin="3,3,3,3">
   <Button HorizontalAlignment="Stretch" Margin="0,0,0,0" x:Name="startStopButton" Width="100" Height="Auto" BorderThickness="0,0,0,0" Content="Start Camera" Click="startStopButton_Click"/>
   <Button x:Name="optionsButton" Width="61.474" Height="Auto" BorderThickness="0,0,0,0" Content="Options" Click="optionsButton_Click"/>
  </WrapPanel>
  <Grid Visibility="Visible" d:LayoutOverrides="HorizontalAlignment, VerticalAlignment" HorizontalAlignment="Right" Margin="0,0,16,16" x:Name="propertyPanel" VerticalAlignment="Bottom" Width="169.237" Height="81.455" Grid.ColumnSpan="2" Grid.Row="1">
   <Rectangle Stroke="#FFFFFFFF" StrokeThickness="3" Margin="0,0,0,0">
    <Rectangle.BitmapEffect>
     <DropShadowBitmapEffect/>
    </Rectangle.BitmapEffect>
    <Rectangle.Fill>
     <LinearGradientBrush EndPoint="1,0.5" StartPoint="0,0.5">
      <GradientStop Color="#FF1E212F" Offset="0"/>
      <GradientStop Color="#FF313551" Offset="1"/>
     </LinearGradientBrush>
    </Rectangle.Fill>
   </Rectangle>
   <Slider HorizontalAlignment="Stretch" Margin="62.633,5,4.681,0" x:Name="exposureSlider" VerticalAlignment="Top" Width="Auto" Height="Auto" Orientation="Horizontal" Maximum="255" ValueChanged="exposureSlider_ValueChanged"/>
   <Label x:Name="serialLabel_Copy" FontSize="10" FontWeight="Bold" Foreground="#FFDEDADA" Content="Exposure" HorizontalAlignment="Left" Margin="3.853,3.853,0,0" VerticalAlignment="Top" Width="57.352">
    <Label.BitmapEffect>
     <OuterGlowBitmapEffect GlowColor="#FF000000" GlowSize="4" Opacity="0.7"/>
    </Label.BitmapEffect>
   </Label>
   <Label x:Name="serialLabel_Copy1" FontSize="10" FontWeight="Bold" Foreground="#FFDEDADA" Content="Threshold" d:LayoutOverrides="Height" HorizontalAlignment="Left" Margin="3.853,27.691,0,0" VerticalAlignment="Top" Width="59.829">
    <Label.BitmapEffect>
     <OuterGlowBitmapEffect GlowColor="#FF000000" GlowSize="4" Opacity="0.7"/>
    </Label.BitmapEffect>
   </Label>
   <Slider x:Name="thresholdSlider" Width="Auto" Orientation="Horizontal" Maximum="253" d:LayoutOverrides="Height, Margin" Margin="62.633,27.691,4.681,0" VerticalAlignment="Top" Minimum="54" Value="54" ValueChanged="thresholdSlider_ValueChanged"/>
   <Button x:Name="greyScaleButton" Width="75.333" Content="Greyscale" Click="greyscaleButton_Click" HorizontalAlignment="Left" Height="21" d:LayoutOverrides="Height" Margin="8,53.761,0,0" VerticalAlignment="Top"/>
   <Button x:Name="Overlay" Height="21" Content="Overlay" Click="OverlayButton_Click" d:LayoutOverrides="Height" HorizontalAlignment="Right" Margin="0,53.761,8,0" VerticalAlignment="Top" Width="64"/>
  </Grid>
 </Grid>
</UserControl>

Answer 1

Topmost 属性存在于 Window 类中： http://msdn.microsoft.com/en-us/library/system.windows.window.topmost.aspx。

您的CameraView 类派生自UserControl，它是一种位于Window（或其他容器，例如Page，但这在这里并不重要）内的控件。 UserControl 没有 Topmost 属性，因为它不会独立出现在桌面上。

将您的 CameraView 托管在一个窗口中，并设置 Window.Topmost:

<!-- MyWindow.xaml -->
<Window ...
        xmlns:local="clr-namespace:TestProject"
        Topmost="True">
  <local:CameraView />
</Window>

其中省略号代表 Visual Studio 为您创建的默认内容，例如 x:Class 和 WPF xmlns 声明。

Answer 2

在后面的 UserControl 代码中，您可以获得对托管它的窗口的引用，然后设置 Topmost 属性。例子，

Window parent = Window.GetWindow(this);
parent.Topmost = true;

Answer 3

这是用户控件。您只能为 Windows 设置 TopMost 属性