Category: .Net

[code language=”csharp”]
catch (OutOfMemoryException ex)
{
Log.Error("Error")
}
[/code]
Severity Code Description Project File Line Suppression State
Error CS0168 The variable ‘ex’ is declared but never used

To suppress this code remove variable and simply write catch block like this-
[code language=”csharp”]
catch (OutOfMemoryException)
{
Log.Error("Error")
}
[/code]

C# 6 Local functions are useful to create helper methods and was written as below-

 
public class LocalFunctions
{
    public int Age { get; set; }

    public string C6PrivateFunction()
    {
       return $"C#6 ==> Person is {GetEligibility(Age)}";
    }        
}

private string GetEligibility(int age)
{
   return age > 18 ? "Adult" : "Youth";
}

With C# 7.0 the same can be written as below.

Inside local functions, variables and parameters from the enclosing scope are also available and the same can also be written using as expression body.

        
public string C7LocalFunction()
{
   return $"C#7 ==> Person is {GenerateEligibility(Age)}";

   string GenerateEligibility(int age)
   {
      return age > 18 ? "Adult" : "Youth";
   }
}

public string C7LocalFunction1()
{
   return $"C#7 ==> Person is {GenerateEligibility(Age)}";

   string GenerateEligibility(int age) =>  age > 18 ? "Adult" : "Youth";
}

Enjoy coding!!!

C# 7.0 introduced throw expression, throwing exception has always been a statement and need to call a method to throw exception. Syntax is same as you’ve always used to throw exceptions difference is it can be also placed in the conditional expressions

With c# 7.0 exceptions can be thrown directly from within expression as shown below-

 public class ThrowExpressions
 {
 public static string ThrowExpressionMethod(string someString)
 {
 return string.IsNullOrWhiteSpace(someString) ? throw new ArgumentNullException("someString is empty") : someString;
 }
 }

Numeric literal syntax

Reading numbers makes it difficult to understand code. C# 7 has improvement done on the digit separator.

public static int IntegerLiterals()
 { return 1_000_000; }

public static double DoubleLiterals()
 { return 9_8_7.1_2_3; }

public static int BinaryLiterals()
 { return 0b0001_0000; }

 Console.WriteLine($" One Million : {NumericalLiterals.IntegerLiterals()}");
 Console.WriteLine($" Double : {NumericalLiterals.DoubleLiterals()}");
 Console.WriteLine($" Binary to Decimal : {NumericalLiterals.BinaryLiterals()}");

Output:

One Million : 1000000
Double : 987.123
Binary to Decimal : 16

Inline out variables

Earlier declaring out variables has to be done separately. Now this can be done in line as follows

public static int InlineOutVariables()
 {
 string input = "100";
 if (!int.TryParse(input, out int result))
 {
 return 0;
 }
 return result;
 }

You can declare out variable where you use it.  The declared out variables also leaks out of the if statement scope and used later.

Consider if you want to use if and only if condition (IIF) with a nullable type

DateTime? foo;
foo = true ? null : new DateTime(0);

This will throw a compiler error. To resolve this cast null to nullable type as below-

foo = true ? (DateTime?)null : new DateTime(0);

These are some of the LINQ syntax for immediate query execution (more to add)-
1. ToList()

2. FirstOrDefault

3. Aggregate Methods (like Count(), Sum() etc.)

4. AsEnumerable()

As I said there are more to add, will keep updating as and when I find more methods.

Happy Coding!!!