Cause

A public or protected type is defined outside the scope of a named namespace.

Rule description

Types are declared in namespaces to prevent name collisions, and as a way to organize related types in an object hierarchy. Types that are outside any named namespace are in a global namespace that cannot be referenced in code.

How to fix violations

To fix a violation of this rule, place the type in a namespace.

When to suppress warnings

Although you never have to suppress a warning from this rule, it is safe to do this when the assembly will never be used together with other assemblies.

Suppress a warning

If you just want to suppress a single violation, add preprocessor directives to your source file to disable and then re-enable the rule.

#pragma warning disable CA1050// The code that's violating the rule is on this line.#pragma warning restore CA1050

To disable the rule for a file, folder, or project, set its severity tonone in theconfiguration file.

[*.{cs,vb}]dotnet_diagnostic.CA1050.severity = none

For more information, seeHow to suppress code analysis warnings.

Example 1

The following example shows a library that has a type incorrectly declared outside a namespace, and a type that has the same name declared in a namespace.

// Violates rule: DeclareTypesInNamespaces.using System;public class Test{    public override string ToString()    {        return "Test does not live in a namespace!";    }}namespace ca1050{    public class Test    {        public override string ToString()        {            return "Test lives in a namespace!";        }    }}

' Violates rule: DeclareTypesInNamespaces.Public Class Test         Public Overrides Function ToString() As String                Return "Test does not live in a namespace!"        End Function     End ClassNamespace ca1050    Public Class Test        Public Overrides Function ToString() As String            Return "Test lives in a namespace!"        End Function    End ClassEnd Namespace

Example 2

The following application uses the library that was defined previously. The type that's declared outside a namespace is created when the nameTest is not qualified by a namespace. To access theTest type that's declared inside a namespace, the namespace name is required.

public class MainHolder{    public static void Main1050()    {        Test t1 = new Test();        Console.WriteLine(t1.ToString());        ca1050.Test t2 = new ca1050.Test();        Console.WriteLine(t2.ToString());    }}

Public Class MainHolder    Public Shared Sub Main1050()        Dim t1 As New Test()        Console.WriteLine(t1.ToString())        Dim t2 As New ca1050.Test()        Console.WriteLine(t2.ToString())    End SubEnd Class