ConditionalAttribute Class

Indicates to compilers that a method call or attribute should be ignored unless a specified conditional compilation symbol is defined.

System::Object
  System::Attribute
    System.Diagnostics::ConditionalAttribute

Namespace:  System.Diagnostics
Assembly:  mscorlib (in mscorlib.dll)

[SerializableAttribute]
[AttributeUsageAttribute(AttributeTargets::Class|AttributeTargets::Method, AllowMultiple = true)]
[ComVisibleAttribute(true)]
public ref class ConditionalAttribute sealed : public Attribute

The ConditionalAttribute type exposes the following members.

  NameDescription
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsConditionalAttributeInitializes a new instance of the ConditionalAttribute class.
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  NameDescription
Public propertySupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsConditionStringGets the conditional compilation symbol that is associated with the ConditionalAttribute attribute.
Public propertyTypeIdWhen implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute.)
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  NameDescription
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsEqualsInfrastructure. Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute.)
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsGetHashCodeReturns the hash code for this instance. (Inherited from Attribute.)
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodIsDefaultAttributeWhen overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute.)
Public methodSupported by the XNA FrameworkMatchWhen overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute.)
Public methodSupported by the XNA FrameworkSupported by Portable Class LibrarySupported in .NET for Windows Store appsToStringReturns a string that represents the current object. (Inherited from Object.)
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  NameDescription
Explicit interface implemetationPrivate method_Attribute::GetIDsOfNamesMaps a set of names to a corresponding set of dispatch identifiers. (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute::GetTypeInfoRetrieves the type information for an object, which can be used to get the type information for an interface. (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute::GetTypeInfoCountRetrieves the number of type information interfaces that an object provides (either 0 or 1). (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute::InvokeProvides access to properties and methods exposed by an object. (Inherited from Attribute.)
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You can apply the ConditionalAttribute attribute to methods and classes. However, its use on classes is valid only for types that are derived from Attribute. ConditionalAttribute either will be ignored or will produce a compiler warning or error message if you apply it to any other type.

Applying ConditionalAttribute to a method indicates to compilers that a call to the method should not be compiled into Microsoft intermediate language (MSIL) unless the conditional compilation symbol that is associated with ConditionalAttribute is defined. You will get a compilation error in Visual Studio if you apply this attribute to a method that does not return void. Applying ConditionalAttribute to an attribute indicates that the attribute should not be emitted to metadata unless the conditional compilation symbol is defined. Any arguments passed to the method or attribute are still type-checked by the compiler.

You can use the following techniques to define conditional compilation symbols:

  • Use compiler command-line options; for example, /define:DEBUG.

  • Use environment variables in the operating system shell; for example, set DEBUG=1.

  • Use pragmas in the source code; for example, define the compilation variable as follows:

    No code example is currently available or this language may not be supported.

    To undefine the variable, use the following:

    No code example is currently available or this language may not be supported.

Compilers that comply with the Common Language Specification (CLS) are permitted to ignore ConditionalAttribute. The C#, Visual Basic, and C++ compilers support ConditionalAttribute; the JScript compiler does not support the attribute.

NoteNote

In Visual Basic, the AddressOf operator is not affected by this attribute. For example, Call CType(AddressOf delegate, Action) always invokes delegate, although Call delegate() might not.

ConditionalAttribute is applied to the methods that are defined in the Debug and Trace classes.

For more information about how to use attributes, see Extending Metadata Using Attributes.

The following example demonstrates the use of ConditionalAttribute. The example assumes that the condition is defined with the /define compiler option. You can obtain different results by changing the compiler option. You can optionally define the conditions by using pragmas in the sample code instead of identifying them as compiler options.

No code example is currently available or this language may not be supported.

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

.NET for Windows Store apps

Supported in: Windows 8

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone 8, Silverlight 8.1

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
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