Here, we will learn what is a partial class in c#, how to define and use partial classes in c#, and what are rules we need to follow to create partial classes in c# with examples.
As discussed in the C# Tutorial, splitting the functionality of a particular class into multiple class files using the partial
keyword is called a partial class in c#.
Generally, partial classes are useful when multiple developers want to work on the same class file at the same time. In larger projects, the partial classes will provide the ability for multiple developers to work on the same class file simultaneously.
To create the partial classes in c#, we need to define the multiple class files with the same class name using the partial
keyword. During the application compilation time, the compiler will combine all the partial classes into a single class.
The following diagram will illustrate the implementation of partial classes in c#.
As discussed, to create the partial classes we need to define the classes with partial
keyword. Following is the syntax of defining the partial class in c#.
If you observe the above partial classes syntax, we split the Products class functionality into two different class files (File1.cs, File2.cs) using partial
keyword.
During the compilation time, the compiler will combine partial class files (File1.cs, File2.cs) into a single Products class as shown below.
For example, I have Products class with properties, constructors, and methods as shown below.
We can split the functionality of this Products class into two class files using the partial
keyword. For that, create File1.cs and File2.cs class files in your application and split the functionality of Products class based on your requirements and delete the Products class file from the project.
If you observe the above code, we created Products partial class in File1.cs class file using a partial keyword with required properties and constructor. Here, this keyword represents the current instance of the class.
If you observe the above code, we created Products partial class in File2.cs class file using partial
keyword with the required method.
To create partial classes in c#, we need to follow the rules. Following are the rules that we need to follow while implementing the partial classes in c#.
partial
keyword to split the functionality of a particular class into multiple class files and all the class files must be available during the compile time to combine all the partial classes into a single class file.Following is the complete example of creating the partial classes in c# by splitting the functionality of a particular class into multiple files using the partial
keyword.
If you observe the above partial class example, the functionality of Products class is split across multiple files (File1.cs and File2.cs) using the partial
keyword. During the application compilation, both the partial classes will be merged into a single class.
When we execute the above example, we will get the result below.
The main advantage of partial class in c# is to split the functionality of the class into multiple class files. In c#, we can also create partial methods, interfaces, or structures by splitting the functionality of a particular structure, interface, or method into two or more source files using the partial keyword based on our requirements.