Tips and tricks in C# .NET
January 31, 2018 Leave a comment
Say you need to work with relatively large numbers in your C# code:
int number = 3452123;
Wouldn’t it be nice if you could use some kind of delimiter to indicate the millions, thousands etc? Like in 3,452,123? In C# 7.0 the underscore provides a solution for this:
int number = 3_452_123;
The underscores will be ignored by the compiler.
View all various C# language feature related posts here.
January 23, 2018 2 Comments
Occasionally it happens that we want to group related code within a function without creating another private function for that. C# 7.0 provides a neat way for that in the form of local functions which are functions within functions.
Consider the following example:
public class LocalFunctionsDemo
{
public void RunDemo()
{
int GetDiff(DateTime first, DateTime second)
{
TimeSpan ts = (second - first).Duration();
return Convert.ToInt32(ts.TotalDays);
}
int dayDiff = GetDiff(DateTime.UtcNow, DateTime.UtcNow.AddHours(10));
Console.WriteLine(dayDiff);
}
}
January 22, 2018 Leave a comment
C# 7.2 comes with a new access modifier “private protected”. It sounds like a weird combination so let’s see how the various access modifiers in the current release of C# work.
Let’s start with an abstract class called Animal:
public abstract class Animal
{
private String privateName = "Private name";
protected String protectedName = "Protected name";
protected internal String protectedInternalName = "Protected internal name";
private protected String privateProtectedName = "Private protected name";
public String publicName = "Public name";
}
January 18, 2018 1 Comment
Async methods have the tendency to bubble up to the top of the call chain. Asynchronous repository calls in a large web application are often accompanied by asynchronous methods in the controllers as well.
However, this has until recently posed a problem in Console applications where the “top” function is Main. The Main function, as we all know, must adhere to a small number of rules, one of which being that it must either be void or return an integer in case we care about the exit code. So what could we do if we wanted to call upon an asynchronous method from Main? We couldn’t change its signature unfortunately to make it async so we turned to other ways like calling GetAwaiter().GetResult() on the awaitable method.
C# 7.1 solves this problem by enabling another type of Main method signature:
January 17, 2018 2 Comments
By now probably all .NET developers are aware of the await and async keywords, what they do and how they work.
Here’s a small example where the CalculateSum function simulates a potentially time-consuming mathematical operation:
public class AsyncValueTaskDemo
{
public void RunDemo()
{
int res = CalculateSum(0, 0).Result;
Console.WriteLine(res);
}
private async Task<int> CalculateSum(int a, int b)
{
if (a == 0 && b == 0)
{
return 0;
}
return await Task.Run(() => a + b);
}
}
January 16, 2018 Leave a comment
C# 7.0 has been quickly enhanced with a couple of new features in 7.1 and 7.2. If you start Visual Studio 2017 and try e.g. the new “private protected” access modifier then the compiler may not accept it:
public abstract class Animal
{
private String privateName = "Private name";
protected String protectedName = "Protected name";
protected internal String protectedInternalName = "Protected internal name";
private protected String privateProtectedName = "Private protected name";
public String publicName = "Public name";
}
If it puts a red line under “private protected” saying that this access modifier combination is not allowed then you’ll know that C# 7.2 has not been enabled yet.
January 15, 2018 Leave a comment
C# 7.0 makes it possible to throw exceptions with ternary and null-coalescing operators.
Here’s an example where we throw an exception if the divisor is 0:
private double Divide(double what, double withWhat)
{
return withWhat != 0 ? what / withWhat : throw new ArgumentException("nono");
}
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