Wednesday, January 31, 2018

Visual C# Technical Guru - December 2017

Another month as a judge in Microsoft TechNet Guru Awards under Visual C# category. The TechNet Guru Awards celebrate the technical articles on Microsoft TechNet.

Post in WikiNinjas Official Blog,
image
Visual C# Technical Guru - December 2017
Happy Coding.

Regards,
Jaliya

Tuesday, January 23, 2018

Rename/Move Files and Directories using git-mv

If you have used git, I am sure you must have experienced this where you have renamed files/folders specially a case change, it won't reflect in the remote. For instance, if you rename a file from helloworld.txt to helloWorld.txt or HelloWorld.txt, even though it's changed in the local, it won't get changed in the remote. 

In such cases, git-mv is a really handy command. A guy named Patrick Wied has written this wonderful post back in 2012 explaining use of git-mv with different scenarios. Great post!

Hope this helps.

Happy Coding.

Regards,
Jaliya

Wednesday, January 17, 2018

Getting Started with Azure Functions

Serverless Computing has become a trending area in Azure than ever before. Basically, Serverless Computing is completely abstracting away the required resources from your concerns. It acts in an event-driven manner, resources are utilized only when you want them to, those are not up and running when you are not using them. So you are getting billed for only for what’s being used. You don’t have to worry about anything else.

When talking about Serverless Computing in Azure, as of today Azure provides following 3 set of features.
  1. Functions - Serverless Compute
  2. Logic Apps - Serverless Workflow
  3. Event Grid - Serverless Events
In this post, let’s see how we can get started with Azure Functions.

First, open up the Azure Portal. Go to New and search for “functions”. And click on Function App.
1. create
Function App
From the next panel, click on Create.
1.1 create
Create
From the next screen, fill in the details as required. For the Hosting Plan, let’s go ahead with the Consumption Plan because we can then get billed per execution of our functions.
3.  create config
New Function App Details
Once the function app is created. Find the created function app by going to More services and searching.
4. find function apps
Find Function Apps
And you should see all your function apps.
image
Function App
Now when you can click on created function app, you will something like below.
5. function app - overview
Function App: Overview
You can find the function app URL under Overview tab. If you click on the URL, an application will open, just as an App Service.
5. url-running
Function App
Function apps’ Settings is under Platform features.
5. function app - platform features
Function App: Platform Features
Right now to get us keep going, let’s create a Function. Click on Functions and then New Function as below.
6. new function
New Function
You are presented with a set of templates.
7. select template
Select Template
All the languages available are as follow (please note, for some of the languages all the templates are not available).
7. languages
Available Languages
First, let’s create an HTTP Trigger.
image
New HTTP Trigger
I have selected Language as C#. For the Name, you can give whatever the name you want. And then we need to select the Authorization level.
  • Function - A function-specific API key is required. This is the default value if none is provided.
  • Anonymous - No API key is required.
  • Admin - The master key is required.
Let’s go ahead with Anonymous for the purpose of the demo.

Once the function is created, you are presented with a page with a csx file. csx stands for C# Script file. Here you can edit the body of the Run method. Please note, you need to have the method signature as it is.

On the Test panel, let’s change the HTTP Method to GET and add in a new query parameter ‘’name”. Give it some value and click on Run, and you can see your Azure Function is running.
8. httptrigger
run.csx
You can get the function’s URL as above, let’s just copy it into a notepad.

To make the demo nicer, let’s add another function, this time a Timer trigger.
image
New Timer Trigger
I have selected C# as the Language, some Name and you can see the Schedule is expressed as a CRON expression. I have updated the CRON expression to every second.

Like the previous function, you will see the Run method, here let’s modify the method to send an HTTP GET to our previously created function.
using System;
 
public static async Task Run(TimerInfo myTimer, TraceWriter log)
{
    var client = new HttpClient();
    var response = await client.GetAsync("{FunctionUrl}?name=John");
    var result = await response.Content.ReadAsStringAsync();
 
    log.Info($"C# Timer trigger function executed at: {DateTime.Now}, Result: {result}");
}
You can replace the {FunctionUrl} with the URL we have copied over to notepad. And let’s run it. You can see our Timer trigger function is executing every second calling the HTTP trigger function.
9 - time trigger log
Timer Trigger Running Log
Isn’t it nice or what?

Happy Coding.

Regards,
Jaliya

Monday, January 15, 2018

Passing Nullable Value for a DbCommand Parameter

I had this requirement where I wanted to pass a nullable property for a Parameter in DbCommand.
public void Execute(int? someId)
{
    using (DbCommand dbCommand = _context.Database.GetDbConnection().CreateCommand())
    {
        dbCommand.CommandType = CommandType.StoredProcedure;
        dbCommand.CommandText = "sp_SomeStoredProcedure";
        dbCommand.Parameters.Add(new SqlParameter("ParameterId", someId);

        // some code
    }

    // some code
}
I was expecting when someId is null, ADO.NET will consider passing null for the parameter. But apparently, that doesn't seem to be the case. Got required parameter is not supplied error. I even tried below which I felt would work,
dbCommand.Parameters.Add(new SqlParameter("ParameterId", someId.HasValue ? someId.Value : null));
But kept getting the error. Finally, Null coalescing operator with DBNull was there to my rescue.
dbCommand.Parameters.Add(new SqlParameter("ParameterId", someId ?? (object)DBNull.Value));
Happy Coding.

Regards,
Jaliya

Monday, January 8, 2018

C# 7.2 : in Parameters

With C# 7.2, a nice set of syntax improvements that enable working with value types were introduced. My favorite among these is in Parameters.

In this post let’s see what in parameters really is.

As you have already know C# had ref and out for a quite a while now. If we recall what ref and out does (within parameter modifier context), it’s basically as follows.
static void Main(string[] args)
{
    Method1(out int i);
    Console.WriteLine(i); // 10
 
    Method2(ref i);
    Console.WriteLine(i); // 20
}
 
static void Method1(out int i)
{
    // Variable i needs to be assigned a value before leaving the method
    i = 10;
}
 
static void Method2(ref int i)
{
    // Variable i might/might not be assigned a value before leaving the method
    i = 20;
}
Both were used to pass the parameter by reference. The difference is when using out parameter, variable needs to be assigned a value before returning from the method. In ref parameter, there is no such requirement, within the method being called you can or not assign a value to ref parameter. But since there is a possibility of a value not being set there, before passing the ref parameter, it should have a value assigned.

But here from the caller, there is no option to say, within the method being called, the parameter should stay as readonly (if we make the parameter readonly, it’s affecting for outside use of the variable as well).

For this comes the in parameters.
static void Main(string[] args)
{
    Method1(out int i);
    Console.WriteLine(i); // 10
 
    Method2(ref i);
    Console.WriteLine(i); // 20
 
    Method3(i);
    Console.WriteLine(i); // 20
}
 
static void Method1(out int i)
{
    // Variable i needs to be assigned a value before leaving the method
    i = 10;
}
 
static void Method2(ref int i)
{
    // Variable i might/might not be assigned a value before leaving the method
    i = 20;
}
 
static void Method3(in int i)
{
    // Variable i is 20 and cannot assign a value
}
You can see, we have Method3 which accepts int i with in modifier. Unlike out and ref, when we are calling the methods which has in parameters, we don’t have to call like Method(in i). We can omit the in modifier, because the variable is going to be readonly within the method being called. Trying to set a value for in parameters from the method being called is illegal.

Isn’t it nice!

Happy Coding.

Regards,
Jaliya

Saturday, January 6, 2018

No CREATE OR ALTER before Microsoft SQL Server 2016 SP1

In one of the applications that I am working on, there was a stored procedure pushed in by a fellow developer as follows.
ALTER PROCEDURE [someSchema].[someProcedureName]
//--implementation
Since I didn’t have the procedure in my local Microsoft SQL Server database, I have changed the procedure with following and pushed back.
CREATE OR ALTER PROCEDURE [someSchema].[someProcedureName]
//--implementation
The change is I have made is from ALTER PROCEDURE to CREATE OR ALTER PROCEDURE. Then to my surprise got to know that, the stored procedure is breaking on my fellow developer's environment. He was having Microsoft SQL Server 2014 and I am on Microsoft SQL Server 2017.

Did some googling and got to know that CREATE OR ALTER was introduced with as part of Microsoft SQL Server 2016 SP1 enhancements.

For more  information read the following post,
Developers Choice: CREATE OR ALTER

Happy Coding.

Regards,
Jaliya

Friday, January 5, 2018

C# 7 Point Releases

C# 7.0 was publicly released on March, 2017 with the release of Visual Studio 2017. Prior to C# 7, there was less to no discussion about point releases to C# language version (citation needed). But with C# 7, the story is not the same. As of today, we already have C# 7.1 and 7.2.

C# 7.1 was released on August, 2017 with Visual Studio 15.3 while 7.2 was released on December, 2017 with Visual Studio 15.5.

Here is a list of features which got available with point releases.

C# 7.1
  • async Main method
  • default literal expressions
  • Inferred tuple element names
C# 7.2
  • Reference semantics with value types
  • Non-trailing named arguments
  • Leading underscores in numeric literals
  • private protected access modifier
Visual Studio 2017 lets you select the language version for your project. Go to Project Properties -> Build -> Advanced. You can decide whether you are going to live by the edge or not.
image
Project Language Version
Happy Coding.

Regards,
Jaliya