code compiled

AI and other technologies

ashish

Check installed versions of .NET Core sdk and runtime

by Leave a Comment

The dotnet is a tool for working with dotnet core applications.You can perform various useful tasks using this.There are two different concepts in .NET Core,runtime and sdk.The sdk includes everything to develop,run and publish applications wile runtime just allows to run the applications.

To check if dotnet core is installed you can use the following command at the command prompt

where dotnet

this command will give the location where the dotnet core is installed.

Now you can check the version of the dotnet core cli using the following command

dotnet --version

To check the sdks installed on your machine you can use

dotnet --list-sdks

installed-sdk-list

To check the runtimes installed on your machine you can use

dotnet --list-runtimes

 

Hello world using Docker

by Leave a Comment

To view all the commands you can use in your docker installation use the following

docker –version

you can also use the help command to get the list of available commands as:

docker help

to get information about any specific command use:

docker help <command name>

for example to get information about run command:

docker help run

Hello world

There is a prebuilt image provided by docker for the hello world

After you have installed docker you can run the hello-world image using the following

>docker run hello-world

After you execute the above command following message will be displayed on screen:

Hello from Docker!

Docker registry allows to retrieve and store docker images.You can distribute docker images using registry.You can use private registry or public registry.A widely used public registry is Docker Hub.You can pull images from docker hub or store your images in docker hub.

To pull an image from docker hub use

docker pull Image-Name

for example to pull image for mongodb

docker pull mongo

service fabric image

docker pull microsoft/service-fabric-onebox

list all the running containers

docker ps

list all the container images locally

docker images

Remove docker image

you can remove docker image from your computer using the following command:

docker rmi Image Image-ID

 

Run MySQL Server in a docker container

by Leave a Comment

You can pull the MySQL image from the docker hub and run the container.So,you will be able to run MySQL on your machine without installing it.These are the main steps you need to follow for donaloding and running MySQL docker container on your local machine:-

1.pull image from docker hub

docker pull mysql/mysql-server:latest

2.This will download the docker image for MySQL.Now you need to check the password as you will need it when you will run the container.To get the password execute the following command:

docker logs mysql01

docker-connect mysql

3.Now you need to start the container in interactive mode.You can execute the following command :-

docker exec -it mysql01 mysql -uroot -p

Now you will get the mysql prompt

mysql>

4.If you try to execute any command you will get the following error message:-

ERROR 1820 (HY000): You must reset your password using ALTER USER statement before executing this statement.

5.To resolve this error you need to change the password:-

ALTER USER 'root'@'localhost' IDENTIFIED BY 'password';

 

Switch statement in C#

by Leave a Comment

Switch statement is one of the conditional statements in c# such as if else.Switch statement in C# is a concise way of writing conditions specially when your code is cluttered with lots of else if conditions,which is making code difficult to read.

It is used for selecting one of the blocks from a list of code blocks.The code block to execute is determined based on the value of the match expression.The keywords used in switch statement are:

  • switch It accesses the matchExpression in the beginning.
  • case It defines various constant values which are matched with the matchExpression

its syntax is

switch(matchExpression)
{
case Value1:
code block1;
break;

case Value2:
case Value3:
code block2;
break;

default:
code block default;
break;

}

Following is a simple switch case statement:

switch(num)
{
case 1:
Console.WriteLine("Case 1");
break;

case 2:
Console.WriteLine("Case 2");
break;
case 3:
case 4:
Console.WriteLine("Case 3");
break;

default:
Console.WriteLine("not found"); ;
break;

}

It will check the value of the num variable in the beginning and based on that value it will execute the appropriate case statement.If none of the case statement matches then default case will be executed and “not found” will be displayed.

You can notice above that we used same code block for both Case 3 and Case 4.This is allowed in C# and you could write common logic for multiple cases this way.

Filed Under: C#

Overview of ASP.NET Core

by Leave a Comment

ASP.NET framework is built on top of .net framework which was released more than 15 years back.The shortcomings of asp.net webforms such as limited control over the generated html and testability are overcome in asp.net MVC framework

ASP.NET MVC is built on the asp.net framework,based on System.Web.dll assembly.This has the implication of asp.net mvc being totally dependent upon this dll and so any change in this could break the entire application.So a modular approach is definitely required to resolve this.

Another restriction of ASP.NET is that it can run only on Windows OS.A cross platform solution is required to resolve this issue.

ASP.NET Core addresses all of these issues:

  • It is not dependent on any single dll rather it uses single nugets to implement its functionality
  • It is cross platform and can run on any OS such as Linux,Mac etc.
  • Also it is open source

You can build asp.net core applications on top of either .net core framework or .net framework.You should decide this based on your requirement.If you have an existing asp.net application then you can move it to asp.net core easily by target.

Following are the main things which happen when you develop ASP.NET Core application

  • You write a.NET Core console application then you start a Web server this web server provides access to your application logic
  • When you create ASP.NET core application you can use a cross-platform web server called Kestrel.
  • Browser sends a request to a reverse proxy server such as IIS which forwards the request to Ketrel.Then the request passes through the pipeline of middleware  components.