Pass values (parameters) between XAML pages

1 – Using the query string
Navigating page:

page.NavigationService.Navigate(new Uri("/Views/Page.xaml?parameter=test", UriKind.Relative));

Destination page:

string parameter = string.Empty;
if (NavigationContext.QueryString.TryGetValue("parameter", out parameter)) {
    this.label.Text = parameter;
}

2 – Using NavigationEventArgs
Navigating page:

page.NavigationService.Navigate(new Uri("/Views/Page.xaml?parameter=test", UriKind.Relative));

// and ..

protected override void OnNavigatedFrom(NavigationEventArgs e)
{
    // NavigationEventArgs returns destination page
    Page destinationPage = e.Content as Page;
    if (destinationPage != null) {

        // Change property of destination page
        destinationPage.PublicProperty = "String or object..";
    }
}

Destination page:

// Just use the value of "PublicProperty"..

3 – Using Manual navigation
Navigating page:

page.NavigationService.Navigate(new Page("passing a string to the constructor"));

Destination page:

public Page(string value) {
    // Use the value in the constructor...
}

References
https://stackoverflow.com/questions/12444816/how-to-pass-values-parameters-between-xaml-pages

Working with WPF Frame using C# and XAML

<Window x:Class="FrameSample.Window1"  
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"  
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"  
    Title="Window1" Height="300" Width="300">  
    <Grid>          
        <TextBlock>Outside area of frame</TextBlock>  
        <Frame Source="Page1.xaml">              
        </Frame>  
    </Grid>  
</Window>

navigate to a URI in a WPF Frame

<Window x:Class="FrameSample.Window1"  
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"  
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"  
    Title="Window1" Height="300" Width="300">  
    <Grid>  
        <TextBlock>Outside area of frame</TextBlock>  
        <Frame Name="FrameWithinGrid" >  
        </Frame>  
        <Button Height="23" Margin="114,12,25,0"   
                Name="button1" VerticalAlignment="Top" Click="button1_Click">Navigate to C# Corner  
        </Button>  
    </Grid>  
</Window>
private void button1_Click(object sender, RoutedEventArgs e)  
{  
    FrameWithinGrid.Navigate(new System.Uri("Page1.xaml",  
             UriKind.RelativeOrAbsolute));  
}

navigate to an external website URL and opens the ASPX page within a Frame

FrameWithinGrid.Source = new Uri("http://www.c-sharpcorner.com/Default.aspx", UriKind.Absolute);

this code first creates a NavigationWindow and then sets its Source to a URI

NavigationWindow window = new NavigationWindow();  
Uri source = new Uri("http://www.c-sharpcorner.com/Default.aspx", UriKind.Absolute);  
window.Source = source; window.Show();
private void NavigationViewItemHome_OnClick(object sender, RoutedEventArgs e)
{
    FrameMain.Navigate(new PageItems());
}

References
https://www.c-sharpcorner.com/UploadFile/mahesh/using-xaml-frame-in-wpf857/
https://www.youtube.com/watch?v=YoZcAx_0rNM

Template Matching On Images C# using OpenCV

Image<Bgr, byte> Image1 = new Image<Bgr, byte>(Properties.Resources.Image1); //Your first image
        Image<Bgr, byte> Image2 = new Image<Bgr, byte>(Properties.Resources.Image2); //Your second image

        double Threshold = 0.8; //set it to a decimal value between 0 and 1.00, 1.00 meaning that the images must be identical

        Image<Gray, float> Matches = Image1.MatchTemplate(Image2, TemplateMatchingType.CcoeffNormed);

        for (int y = 0; y < Matches.Data.GetLength(0); y++)
        {
            for (int x = 0; x < Matches.Data.GetLength(1); x++)
            {
                 if (Matches.Data[y, x, 0] >= Threshold) //Check if its a valid match
                 {
                     //Image2 found within Image1
                 }
            }
        }

References
https://stackoverflow.com/questions/39570033/template-matching-on-images-c-sharp

Move and Click Mouse in C#

[DllImport("user32.dll")]
public static extern void mouse_event(MouseEventFlags dwFlags, uint dx, uint dy, uint dwData, MouseEventDataXButtons dwExtraInfo);

[DllImport("User32.Dll")]
public static extern long SetCursorPos(int x, int y);
[Flags]
public enum MouseEventFlags : uint
{
    LEFTDOWN = 0x00000002,
    LEFTUP = 0x00000004,
    MIDDLEDOWN = 0x00000020,
    MIDDLEUP = 0x00000040,
    MOVE = 0x00000001,
    ABSOLUTE = 0x00008000,
    RIGHTDOWN = 0x00000008,
    RIGHTUP = 0x00000010,
    WHEEL = 0x00000800,
    XDOWN = 0x00000080,
    XUP = 0x00000100
}

//Use the values of this enum for the 'dwData' parameter
//to specify an X button when using MouseEventFlags.XDOWN or
//MouseEventFlags.XUP for the dwFlags parameter.
public enum MouseEventDataXButtons : uint
{
    XBUTTON1 = 0x00000001,
    XBUTTON2 = 0x00000002
}
public static void MoveMouse(int x, int y)
{
    PInvoke.SetCursorPos(x, y);
}

public static void ClickMouse(int x, int y)
{
    PInvoke.mouse_event(MouseEventFlags.LEFTDOWN | MouseEventFlags.ABSOLUTE, (uint)x, (uint)y, 0, 0);
    Thread.Sleep(10);
    PInvoke.mouse_event(MouseEventFlags.LEFTUP | MouseEventFlags.ABSOLUTE, (uint)x, (uint)y, 0, 0);
}

References
https://stackoverflow.com/questions/13520705/move-mouse-to-position-and-left-click
http://www.pinvoke.net/default.aspx/user32.mouse_event
https://stackoverflow.com/questions/8050825/how-to-move-mouse-cursor-using-c
https://www.pinvoke.net/default.aspx/user32.setcursorpos

Take Screenshot in C#

First Set Process DPI Aware:

Get Screen Size on C#
https://pupli.net/2020/03/get-screen-size-on-c/

Install-Package System.Drawing.Common -Version 7.0.0

Take screenshot and save to file

using System;
using System.Drawing;
using System.Windows.Forms;

namespace ScreenshotExample
{
    class Program
    {
        static void Main(string[] args)
        {
            // Get the bounds of the screen
            Rectangle bounds = Screen.PrimaryScreen.Bounds;

            // Create a bitmap object to store the screenshot
            using (Bitmap bitmap = new Bitmap(bounds.Width, bounds.Height))
            {
                // Create a graphics object from the bitmap
                using (Graphics g = Graphics.FromImage(bitmap))
                {
                    // Capture the screen
                    g.CopyFromScreen(new Point(bounds.Left, bounds.Top), Point.Empty, bounds.Size);
                }

                // Save the screenshot as a PNG file
                bitmap.Save("screenshot.png");
            }

            Console.WriteLine("Screenshot saved as screenshot.png");
        }
    }
}

Take screenshot and save to memory

using System;
using System.Drawing;
using System.IO;
using System.Windows.Forms;

namespace ScreenshotToMemory
{
    class Program
    {
        static void Main(string[] args)
        {
            // Get the bounds of the screen
            Rectangle bounds = Screen.PrimaryScreen.Bounds;

            // Create a bitmap object to store the screenshot
            using (Bitmap bitmap = new Bitmap(bounds.Width, bounds.Height))
            {
                // Create a graphics object from the bitmap
                using (Graphics g = Graphics.FromImage(bitmap))
                {
                    // Capture the screen
                    g.CopyFromScreen(new Point(bounds.Left, bounds.Top), Point.Empty, bounds.Size);
                }

                // Store the screenshot in memory using MemoryStream
                using (MemoryStream memoryStream = new MemoryStream())
                {
                    bitmap.Save(memoryStream, System.Drawing.Imaging.ImageFormat.Png);

                    // Convert the MemoryStream to byte array
                    byte[] screenshotBytes = memoryStream.ToArray();

                    // Now the screenshot is stored in screenshotBytes, you can use it as needed
                    // For demonstration, let's output the length of the byte array
                    Console.WriteLine($"Screenshot captured. Byte array length: {screenshotBytes.Length}");
                }
            }
        }
    }
}

 

Get Screen Size on C#

The process is running under DPI virtualization. So we should apply the DPI aware manifest option to stop DPI virtualization

[DllImport("user32.dll", SetLastError=true)]
static extern bool SetProcessDPIAware();

Then

public enum SystemMetric
{
    VirtualScreenWidth = 78, // CXVIRTUALSCREEN 0x0000004E 
    VirtualScreenHeight = 79, // CYVIRTUALSCREEN 0x0000004F 
}

[DllImport("user32.dll")]
public static extern int GetSystemMetrics(SystemMetric metric);

public static Size GetVirtualDisplaySize()
{
    var width = GetSystemMetrics(SystemMetric.VirtualScreenWidth);
    var height = GetSystemMetrics(SystemMetric.VirtualScreenHeight);

    return new Size(width, height);
}

References
https://stackoverflow.com/questions/28339257/getsystemmetrics-and-tscreen-returns-wrong-value
https://www.pinvoke.net/default.aspx/user32/SetProcessDPIAware.html
https://stackoverflow.com/questions/1317235/c-get-complete-desktop-size
https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-setprocessdpiaware

Deploy .NET Core app on Ubuntu

check if it runs

dotnet run

Deploy in a build directory

dotnet publish --output “ /var/www/build” --configuration release

Go to the build directory and run the application

dotnet ForExample.dll

Create the service file

sudo nano /etc/systemd/system/kestrel-ForExample-test.service
[Unit]
Description=Example .NET Web API App running on Ubuntu
[Service]
WorkingDirectory=/var/www/ForExample/ForExample
ExecStart=/usr/bin/dotnet /var/www/build/ForExample.dll
Restart=always
# Restart service after 10 seconds if the dotnet service crashes:
RestartSec=10
KillSignal=SIGINT
SyslogIdentifier=dotnet-example
User=www-data
Environment=ASPNETCORE_ENVIRONMENT=Production
Environment=DOTNET_PRINT_TELEMETRY_MESSAGE=false
[Install]
WantedBy=multi-user.t

Register the service

sudo systemctl enable kestrel-ForExample-test.service

Start the service and verify that it’s running.

sudo systemctl start kestrel-mebgispanel-test.service
sudo systemctl status kestrel-mebgispanel-test.service

Check the server logs

sudo journalctl -fu kestrel-helloapp.service

References
https://medium.com/faun/ubuntu-servers-and-asp-net-core-project-deployment-using-nginx-d9a3a1f6ac82