C# FAQ: Why must struct constructors have at least one argument

Microsoft .NET Framework, ASP.NET, Visual C# (CSharp, C Sharp, C-Sharp) Developer Training, Visual Studio

Why must struct constructors have at least one argument?

The .NET Common Language Runtime (CLR) does not guarantee that parameterless constructors will be called. If structs were permitted to have default, parameterless constructors, the implication would be that default constructors would always be called. Yet, the CLR makes no such guarantee.

For instance, an array of value types will be initialized to the initial values of its members—i.e., zero for number type primitive members, null for reference types, and so forth—and not to the values provided in a default constructor. This feature makes structs perform better; because, constructor code need not be called.

So, requiring that a constructor contain a minimum of one parameter reduces the possibility that a constructor will be defined which is expected to be called every time the struct type is built.

See also

• Are C# constructors inherited?
• How can one constructor call another?
• Are constructors the same in C++ and C#?
• Are destructors the same in C++ and C#?
• How call a virtual method from a constructor or destructor?
• How do destructors work in C#?
• How enforce constructor correctness in C#?
• How make a C# destructor virtual?
• What are the differences between C# and Java constructors?
• What are the differences between C# finalizers and Java destructors?
• What is the syntax for calling an overloaded constructor from within a constructor?
• Why must struct constructors have at least one argument?