How to use two different languages in a .NET Project

Did you ever try to use two languages in some of your project? Or Say you created a Class in VB.NET and used in C# code. As .NET provides us the capability to use multiple languages in same project, even it allows to inherit a VB.NET class in C# Class.If you have not tried earlier then this post will help you in getting practical examples. So Let’s move to the example

In this example, I have created two projects : one is C# Class library project and other is VB console application. My C# class looks like

    public class Person
        public void Print()
            Console.WriteLine("C# - Person's Print method");

It’s perfectly legal to inherit C# class in vb class. So here my vb class looks like

Public Class Student
    Inherits CLSCompliantCsharp.Person

    Public Sub Display()
        Console.WriteLine("I am Student VB class")
    End Sub
End Class

So here I have just added one more method Display in my class. Let’s move to main method

Module Module1
    Sub Main()
        Dim o As New Student()
    End Sub
End Module

Let’s run it and see the output.

NormalSo it is perfectly fine and run as expected. Now let’s add one more method in my person class as

    public class Person
        public void Print()
            Console.WriteLine("C# - Person's Print method");

        public void print()
            Console.WriteLine("C# - Person's print method");

Now I have added one new method with same name print but it’s first letter is small letter. As we know that C# is case sensitive language so having the method with same name with different case, is perfectly legal.So lets build the C# project after making the changes So it is perfectly builds.

Now again move to the VB project and run the code.

Oh.. it throws a error as

errorAs we can see that it is giving error message that Print is ambiguous because for VB.NET Print() and print() are same while for Csharp different.

So How to deal this?

.NET provides us a way to make a library language neutral i e it defines some basic set of rules that can be applied to any library to make neutral. So if you think that your code/dll might be used by different language then you must apply an attribute to the your assembly.

The attribute is CLSCompliant

So if you want to make it a Class library CLSCompliant then add this attribute in the AssemblyInfo.cs file as

[assembly: CLSCompliant(true)]

I have added the above attribute in my C# project and now lets build it (with having two print method as earlier)

CLSComplaintWarningNow if you see that then it is showing an warning that this code is not CLS-Compliant Now you can correct it. Once you remove all the CLS-Complaint warnings and you can take a deep breath. You wont get any complaint if your code is used on any other language in .NET platform.

CLSCompliant attribute also provides more granular approach. It means if you don’t want to make the entire Class library as CLS-Compliant then you apply this attribute at class level as well. Then compiler will apply this attribute on that class only and that can be used by other language applications accordingly.

Hope you all have enjoyed this post.



What is SecureString ?

In this post, we are going to discuss a class SecureString. Although this class is available since .NET 2.0, but I am sure, many of us would not be knowing or using it. Even I was not aware of this fantastic class few weeks ago. This class can be very useful for you if you are more concerned about your application security.

This class belongs to the namespace System.Security . This class should be used to store the data which is confidential. The text assigned to this string is by default encrypted. This data is also removed as soon as it is not required which in-turn reduces the chances of misuse.

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Working with EventViewer using C#

There are several phases of a Application . It does not end with developing the application and deploying it on production servers. Other most important part, any problem surfaces after the deployment, how quickly the problem can be be resolved and according to severity of the issue (if required) a patch can be deployed on production. Apart from this, we also want to get notified on all the issues occurred on production and accordingly analyze and take care in future releases. We can also log other details that could be useful to check the status of Application.

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Learning null-coalescing operator

I am pretty sure that most of the guys has never knew this operator and its also very rarely used. Since C# provides this and this is very useful and handy at certain times.

The short from of null-coalescing operator is ??.

It actually takes two operands.  So it returns the left hand operand if it is not null else returns right operand. So this is very useful while initializing any variable. let’s see a example

string name = null;
string otherName = "Brij";
string userName = name ?? otherName;

As you can see, here is name is null then userName is assigned to otherName. and it will print Brij.

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Exploring Nullable types : Part 2

This is second and last part of the post on Nullable type series. You can view the first part from here

Exploring Nullable types : Part 1

In this series, I will talking certain rules that we need to take care while using Nullable type. I will be taking scenario wise.

First scenario:

Int? a=8;
object o = a;
long d = (long)c;

It will be compiled successfully but will throw and Invalid Cast Exception. Means, you cannot cast it to any other type except the underlying type which is here int although  int type can be hold by long.

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Generics and Constraints over Generics

In this post,  I am going to discuss about Generic Classes and bit more on this.  Just for a smooth start,

“Generics were introduced in .NET 2.0, which provides us a way to create Classes/Methods/Types and many more without specifing the specific type of parameters. Parameters must be provided at the time of creating the instances. So we can say Generics are only a blueprint/templated version and actual type is defined at Runtime.”

So lets first create a simple Class say Point Continue reading…