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Static holder types should not have constructors







Breaking Change


A public or nested public type declares only static members and has a public or protected default constructor.

The constructor is unnecessary because calling static members does not require an instance of the type. Also, because the type does not have non-static members, creating an instance does not provide access to any of the type's members.

To fix a violation of this rule, remove the default constructor or make it private.


Some compilers automatically create a public default constructor if the type does not define any constructors. If this is the case with your type, add a private default constructor to eliminate the violation.

Do not exclude a warning from this rule. The presence of the constructor suggests that the type is not a static type.

The following example shows a type that violates this rule. Note that there is no default constructor in the source code. When this code is compiled into an assembly, the C# compiler will insert a default constructor, which will violate this rule. To correct this, declare a private constructor.

using System;

namespace DesignLibrary
   public class NoInstancesNeeded
      // Violates rule: StaticHolderTypesShouldNotHaveConstructors.
      // Uncomment the following line to correct the violation.
      // private NoInstancesNeeded() {}

      public static void Method1() {}
      public static void Method2() {}