What is the use of ‘partial’ in C#?

In C#, the partial keyword is used to define classes, structs, and interfaces that can be defined in multiple source files. It allows breaking down the definition of a type into multiple parts, each of which can be written in different source files.

The main purpose of the “partial” keyword is to allow multiple developers to work on the same class or structure simultaneously without each person needing to modify the same source file. This can improve development efficiency and reduce code conflicts.

Here are some examples of how to use the “partial” keyword:

// File1.cs
partial class MyClass
{
    public void Method1()
    {
        Console.WriteLine("Method1");
    }
}

// File2.cs
partial class MyClass
{
    public void Method2()
    {
        Console.WriteLine("Method2");
    }
}

// Main.cs
class Program
{
    static void Main(string[] args)
    {
        MyClass myObject = new MyClass();
        myObject.Method1(); // 输出 "Method1"
        myObject.Method2(); // 输出 "Method2"
    }
}

In the example above, the definition of the MyClass class is split into two parts, each in the File1.cs and File2.cs files. We can then instantiate the MyClass class in the Main.cs file and access its two methods, Method1 and Method2.

It is important to note that all parts must be modified using the “partial” keyword, and their names, access modifiers, and other modifiers must remain consistent. Otherwise, compilation errors will occur.