Tips and tricks in C# .NET
March 6, 2015 1 Comment
The Path class in the System.IO namespace provides a number of useful filepath-related methods. Say that you have the following ingredients of a full file path:
string drive = @"C:\"; string folders = @"logfiles\october\"; string fileName = "log.txt";
March 4, 2015 Leave a comment
How do you read the date “03-10-2014”? For some of you this will be October 03 2014. For others, especially those from the US this will be interpreted as March 10 2014. This is because dates are represented in different formats in different cultures.
Consider the following code:
string dateString = "03-10-2014"; DateTime parsedDate = DateTime.Parse(dateString); string toString = parsedDate.ToLongDateString();
March 3, 2015 Leave a comment
The Array class has a number of interesting methods. One of them allows you to easily convert an array of T into a read-only collection of T:
string[] bands = new string[5] { "Queen", "ACDC", "Metallica", "Genesis", "INXS" };
IReadOnlyCollection<string> readOnlyBands = Array.AsReadOnly<string>(bands);
Note that readOnlyBands is, well, read-only, so there’s no Add or Remove method that otherwise are often available on lists.
View all various C# language feature related posts here.
February 27, 2015 1 Comment
Say you have a class or a class member that you’d like to remove at a later stage. You’ve probably seen compiler warnings or even errors with a message like “abc.efg is obsolete: ‘some message'”.
Let’s see quickly how to achieve it in C#.
The attribute to be aware of is Obsolete. It can decorate both classes, properties and methods. You can attach a useful message to it and make the compiler issue an error instead of the default warning. Let’s see an example:
[Obsolete]
public class CurrentCustomer
{
public void Buy()
{
}
}
February 25, 2015 2 Comments
In this post we saw how to use the “if” preprocessor in Visual Studio to “communicate” with the compiler. Here’s a reminder of the example code which we’ll re-use here:
private static void TryPreprocessors()
{
# if DEBUG
Console.WriteLine("You are running the Debug build");
# elif RELEASE
Console.WriteLine("You are running the Release build");
#else
Console.WriteLine("This is some other build.");
# endif
}
In this post we’ll look at two more preprocessor types: warning and error. If you compile a project you can get one or more errors or warnings:
February 24, 2015 1 Comment
The Array class has a number of useful static methods. A group of them is used for searching purposes. The method names are generally quite descriptive. Here are some them with comments in the code:
string[] bands = new string[6] { "Queen", "ACDC", "Metallica", "Genesis", "INXS", "Motörhead" };
//find the first entry in the array which starts with Q, finds "Queen"
string firstBandStartingWithQ = Array.Find<string>(bands, s => s.StartsWith("Q"));
//finds last entry start with M, finds Motörhead
string lastBandStartingWithM = Array.FindLast<string>(bands, s => s.StartsWith("M"));
//finds Metallica and Motörhead and puts them in an array
string[] allWithM = Array.FindAll<string>(bands, s => s.StartsWith("M"));
//index will be 0 as Queen is the first item in the array
int queenIndex = Array.FindIndex<string>(bands, s => s == "Queen");
//yields true as ACDC figures in the array
bool acdIsThere = Array.Exists<string>(bands, s => s == "ACDC");
View all various C# language feature related posts here.
February 20, 2015 2 Comments
You can decorate your C# source code with “messages” to the compiler. There are a couple of predefined preprocessors that the compiler understands.
A common scenario is when you’d like to run some part of your code in Debug mode but not in Release mode or any other Build type. The following method shows the ‘if’ and ‘elif’ preprocessors:
February 18, 2015 Leave a comment
The ‘partial’ keyword helps you divide your classes into multiple files within the same namespace. One obvious usage of partial classes is to split the definition of a large type into smaller chunks. You cannot just use the partial keyword with classes but methods as well.
The partial classes will reside in two – or more – different cs files in the same namespace. Say you have a partial Customer class in the project-name/domains folder:
February 13, 2015 Leave a comment
Say you have a method which accepts a string parameter. The method may need to handle null values in some way. One strategy is to validate the parameter and throw an exception:
private static string Resolve(string input)
{
if (input == null) throw new ArgumentNullException("Input");
.
.
.
}
Another strategy is to provide some default value with an if-else statement:
February 11, 2015 1 Comment
Let’s say you have the following three numbers:
…and you’d like to format them as follows:
There’s a special format string that can be used for this purpose. It consists of 3 parts separated by a semi-colon. The first part applies to positive numbers, the second to negative numbers and the third to zeroes:
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