Month: March 2021

Install RabbitMQ on Ubuntu 20.04

Install Erlang

wget -O- https://packages.erlang-solutions.com/ubuntu/erlang_solutions.asc | sudo apt-key add -
echo "deb https://packages.erlang-solutions.com/ubuntu focal contrib" | sudo tee /etc/apt/sources.list.d/rabbitmq.list
sudo apt update
sudo apt install erlang

Install RabbitMQ

sudo apt update && sudo apt install wget -y
sudo apt install apt-transport-https -y
wget -O- https://dl.bintray.com/rabbitmq/Keys/rabbitmq-release-signing-key.asc | sudo apt-key add -
wget -O- https://www.rabbitmq.com/rabbitmq-release-signing-key.asc | sudo apt-key add -
echo "deb https://dl.bintray.com/rabbitmq-erlang/debian focal erlang-22.x" | sudo tee /etc/apt/sources.list.d/rabbitmq.list
sudo apt update
sudo apt install rabbitmq-server
sudo systemctl enable rabbitmq-server

RabbitMQ Management Dashboard

sudo rabbitmq-plugins enable rabbitmq_management

To be able to login on the network, create an admin user like below:

rabbitmqctl add_user admin StrongPassword
rabbitmqctl set_user_tags admin administrator

References
https://computingforgeeks.com/how-to-install-latest-erlang-on-ubuntu-linux/
https://computingforgeeks.com/how-to-install-latest-rabbitmq-server-on-ubuntu-linux/

Switch statement in Go

package main

import (
    "fmt"
    "time"
)

func main() {

    i := 2
    fmt.Print("Write ", i, " as ")
    switch i {
    case 1:
        fmt.Println("one")
    case 2:
        fmt.Println("two")
    case 3:
        fmt.Println("three")
    }

    switch time.Now().Weekday() {
    case time.Saturday, time.Sunday:
        fmt.Println("It's the weekend")
    default:
        fmt.Println("It's a weekday")
    }

    t := time.Now()
    switch {
    case t.Hour() < 12:
        fmt.Println("It's before noon")
    default:
        fmt.Println("It's after noon")
    }

    whatAmI := func(i interface{}) {
        switch t := i.(type) {
        case bool:
            fmt.Println("I'm a bool")
        case int:
            fmt.Println("I'm an int")
        default:
            fmt.Printf("Don't know type %T\n", t)
        }
    }
    whatAmI(true)
    whatAmI(1)
    whatAmI("hey")
}

References
https://gobyexample.com/switch

If Statement in Go

package main

import "fmt"

func main() {

    if 7%2 == 0 {
        fmt.Println("7 is even")
    } else {
        fmt.Println("7 is odd")
    }

    if 8%4 == 0 {
        fmt.Println("8 is divisible by 4")
    }

    if num := 9; num < 0 {
        fmt.Println(num, "is negative")
    } else if num < 10 {
        fmt.Println(num, "has 1 digit")
    } else {
        fmt.Println(num, "has multiple digits")
    }
}

References
https://gobyexample.com/if-else

For Loop in Go

package main

import "fmt"

func main() {

    i := 1
    for i <= 3 {
        fmt.Println(i)
        i = i + 1
    }

    for j := 7; j <= 9; j++ {
        fmt.Println(j)
    }

    for {
        fmt.Println("loop")
        break
    }

    for n := 0; n <= 5; n++ {
        if n%2 == 0 {
            continue
        }
        fmt.Println(n)
    }
}

References
https://gobyexample.com/for

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