C# * Tutorial – Complete Guide

Welcome to this exciting tutorial on C# wildcard ‘*’. As an integral part of modern C# programming, understanding and leveraging the functionality of the wildcard ‘*’ is crucial for anyone diving into game development or any application development using the .NET Framework.

What is C# Wildcard ‘*’?

In C#, the wildcard ‘*’ is a fascinating and powerful feature typically used in patterns matching conditions where it substitutes for zero or more characters. It assists developers in dealing with a collection of items and provides a way to simplify complex coding scenarios.

Why should you learn about C# Wildcard ‘*’?

Why invest your time in understanding the wildcard ‘*’ in C#? There are many compelling reasons:

  • It enhances your code readability and maintainability by providing concise and clear syntax.
  • You can manage and filter large data collections efficiently.
  • It increases your productivity by making pattern matching more straightforward.
  • Improved problem-solving capabilities in game development and application development scenarios.

Coding is much like cooking; knowing how to use your ingredients (in this case, programming functionalities) expands your recipe (coding solutions) catalogue. The wildcard ‘*’ is one of those potent ingredients that can spice up your code and make it tastier (more efficient).

Now, let’s get into the kitchen (the coding part) and explore how to cook some amazing dishes (coding solutions) with the wildcard ‘*’ in C#.

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Using C# Wildcard ‘*’ in Method Declarations

A common use of the wildcard ‘*’ operator in C# can be found in method declarations, where it is used for param array parameters, representing a varying number of arguments.

public void ShowNumbers(params int[] numbers)
   foreach (int number in numbers)

In this code, an array of integers is passed to the ShowNumbers method. This array can contain any number of elements.

ShowNumbers(1, 2, 3, 4, 5);  // Output: 1, 2, 3, 4, 5

As we can see, the wildcard ‘*’ allows for the transmission of varying arguments to a method, facilitating flexible code.

Using the Wildcard ‘*’ with Import Directives

Another great use of the wildcard ‘*’ operator is within import directives, allowing you to import all the types in a namespace ensemble.

using System.*;

With this simple directive, you can import all the available types within the System namespace, increasing efficiency and shorthand utilities.

Wildcard in File Systems

In file systems and when working with directories in C#, the wildcard ‘*’ can also be applied effectively. This is useful when you need to perform an operation on a set of files whose names follow a certain pattern.

string[] files = Directory.GetFiles(".", "*.txt");

This code will return all txt files in the current directory.

Wildcard ‘*’ in Regular Expressions

Understanding and using the wildcard ‘*’ in regular expressions can be extremely helpful in pattern matching.

Regex regexPattern = new Regex("a*b");

In this simple regular expression, “a*b” will match a string that has any number (including zero) of ‘a’ characters followed by a ‘b.

Wildcard ‘*’ in LINQ Queries

Language-Integrated Query (LINQ) in C# uses the wildcard ‘*’ in queries to indicate “all fields”. Suppose we have a data object called Students and we want to select all data fields in this object. A LINQ query using wildcard ‘*’ would look like this:

var allFields = from s in Students select *;

Please note, literal usage of ‘*’ to select all fields is not allowed in LINQ-to-SQL queries and is used here for conceptual understanding.

On the other hand, usage of wildcard ‘*’ in string comparisons is very common in Sql-based LINQ-to-Entities queries.

var result = from s in Students
               where SqlMethods.Like(s.Name, "%man%") 
               select s;

This code snippet will return all the students whose name contains the string ‘man’.

Wildcard ‘*’ in Switch Statements

With the introduction of C# 7.0, pattern matching in C# was amped up. One interesting use case of wildcard ‘*’ is in switch-case pattern matching.

public void DisplayShape(Shape shape)
    switch (shape)
        case Circle c:
            Console.WriteLine($"circle with radius {c.Radius}");
        case Rectangle s when (s.Height == s.Length):
            Console.WriteLine($"{s.Length} x {s.Height} square");
        case Rectangle r:
            Console.WriteLine($"{r.Length} x {r.Height} rectangle");
        case null:
            throw new ArgumentNullException(nameof(shape));

In the above scenario, different console statements will be executed depending on the particular shape object that is passed to the DisplayShape method.

Using the wildcard ‘*’ in combination with other elements, patterns, and objects can bring a huge productivity shift that can be super beneficial for a C# programmer. Being able to write efficient and clean code is our ultimate goal at Zenva, and understanding the nuances of wildcard ‘*’ usage in C# puts you one step closer to achieving that.

Wildcard ‘*’ in XML Comments

In C#, you can use XML documentation comments to comment your code effectively, assuring maintainability and readability. Here, the wildcard ‘*’ is used to denote continuation of the comment blocks.

/// <summary>
/// This is an XML documentation comment.
/// It is used to describe the code and its functionality.
/// </summary>
public void MyMethod()
 // Method implementation here. 

All lines within the XML comment start with a ‘///’, indicating continuity in the comment block.

Wildcard ‘*’ in Access Modifiers

Wildcard ‘*’ also comes in handy when working with access modifiers in C#. This is an essential part of every C# developer’s toolkit.

internal class MyClass
    // Only accessible within the same assembly.
    public void MyMethod() 
         // Method implementation here.

The keyword ‘internal’ acts as a wildcard ‘*’ restricting access only to the elements within the same assembly. Therefore, the method ‘MyMethod’ is not accessible in any other assembly.

Wildcard ‘*’ in Arithmetic Operations

In arithmetic operations, the wildcard ‘*’ serves the conventional purpose of multiplication. It is an example that depicts ‘*”s ubiquity across various facets of C#.

int a = 5;
int b = 10;
int c = a * b;  // Output: c = 50

This code shows ‘*’ being used for multiplication in a basic arithmetic operation in C#.

Using Wildcard ‘*’ in Array Mutidimensional Initializers

In C#, the wildcard ‘*’ can be utilized while declaring and initializing multidimensional arrays. It simplifies the process of working with complex data structures.

var numbers = new int[3, 2]
    {2, 4},
    {3, 7},
    {5, *}

In the code above, ‘*’ indicates that the rest of the array elements would remain uninitialized. However, this usage is not universal and will not compile in all C# compilers.

Understanding and mastering the use of C# wildcard ‘*’ paves the way to produce efficient, readable, and reusable code. Its diverse functionality covers a plethora of practical case scenarios, making it an indispensable tool for efficient programming in the .NET Framework. Regardless of what you’re creating – a console application, an intricate game, or a high-traffic web app – understanding the utility of the wildcard ‘*’ can significantly improve your productivity and code performance. As we say at Zenva, “Knowledge is Power!”. Happy coding!

Where to go next

You’ve now ventured into the coding world by understanding the potent tool that is the C# wildcard ‘*’. There’s an exciting journey ahead filled with countless opportunities for learning and growth.

Our Unity Game Development Mini-Degree is a comprehensive collection of courses covering an extensive variety of game development techniques using Unity, a potent game engine whose applications extend beyond gaming to industries like architecture, education, healthcare, and more. This Mini-Degree is project-based with quizzes and challenges, and it’s also suitable for beginners with zero programming experience.

Improving your skills and expanding your knowledge base will always boost your career, and that’s what we offer at Zenva. Check out our [Unity Collections](https://academy.zenva.com/shop/) for an extensive array of high-quality and comprehensive courses. It’s time to shape your future. Happy coding, and we are excited to be a part of your learning journey!


C# programming offers powerful, efficient and flexible solutions for developers. The wildcard ‘*’ operator, with its varied and widespread applications, has a distinct role in enhancing the overall coding experience in this rich platform. True mastery of C# involves understanding and utilizing capabilities such as these – and that’s exactly what you’re set to achieve with us at Zenva.

Tighten your grip on the complexities of C# and similar languages by choosing to learn with us. Our [Unity Game Development Mini-Degree](https://academy.zenva.com/product/unity-game-development-mini-degree/) is specifically designed to mold you into a proficient developer, well-equipped to solve real-world problems. It’s your career, let’s give it wings. Code On!

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