.NET offers the programmer many strongly typed data types. One of those is the System.Boolean structure which represents a Boolean value. System.Boolean, though programmers normally use the bool alias when declaring Boolean variables, have a value of either true or false. These two logical values permit the Boolean data type to represent anything that needs two states, such as, a light switch or indicating whether the player is alive or dead in a video game, and there are many other uses.

System.Boolean Definition

[SerializableAttribute]
[ComVisibleAttribute(true)]
public struct Boolean : IComparable, IConvertible, IComparable<bool>, IEquatable<bool>

The declaration for System.Boolean resides in the System namespace, so when you need to make use of it directly you have to reference the System namespace either directly, or by including it at the top of your module, which in C# is done via the using compiler directive, that is:

using System;

which almost all classes in C# actually do.

A System.Boolean variable will take up precisely one byte of memory. Because bool and System.Boolean are synonymous, you can use the bool keyword almost anywhere you would use System.Boolean, and assign to a bool variable using the true and false literals of C#. These two reserved keywords, true and false, are the only valid Boolean values that can be assigned to the System.Boolean data type.

You can invert a Boolean test by use of the logical not operator, i.e. ! (exclamation point), so that:

bool result = true;
result = !result;

would actually mean that result is equal to Boolean false.

We could of course re-write the above two statements as:

bool result = !true;

Which would assign Boolean false to the result variable, but that makes little actual sense to do at the point of declaration when assigning the true literal.

All members of the System.Boolean structure are considered to be thread safe so you can call them with impunity from your multi-threaded code without having to worry about synchronization issues.

The System.Boolean type exposes the following methods and fields:

Methods Available

	Name	Description
	CompareTo(Boolean)	Compare to another Boolean object and return an integer indicating comparison relationship.
	CompareTo(Object)	Compare to another object and return an integer indicating the comparison relationship.
	Equals(Boolean)	Return a value indicating if this instance is equal to the specified Boolean object.
	Equals(Object)	Return a value indicating if this instance is equal to the specified object.
	Finalize	Attempt to free allocated resources and perform any cleanup necessary before being garbage collected.
	GetHashCode	Return the hash code of this object.
	GetType	Return the Type of the instance.
	GetTypeCode	Return the TypeCode for the value type Boolean.
	MemberwiseClone	Perform a shallow copy of this instance.
	Parse	Attempt to convert a string to its Boolean equivalent. Throws an exception if not possible.
	ToString()	Convert this instance to its equivalent string representation, i.e. "True" or "False."
	ToString(IFormatProvider)	Convert this instance to its equivalent string representation, i.e. "True" or "False."
	TryParse	Attempt to convert a string to its Boolean equivalent. Return value indicates success or failure.

Fields Available

	Name	Description
	FalseString	The Boolean value false as a string. Read-only.
	TrueString	The Boolean value true as a string. Read-only.

Interfaces

	Name	Description
	IConvertible.ToBoolean	Converts the value to an equivalent Boolean value.
	IConvertible.ToByte	Converts the value to an equivalent 8-bit unsigned integer.
	IConvertible.ToChar	Attempts to convert to this type will throw an InvalidCastException.
	IConvertible.ToDateTime	Attempts to convert to this type will throw an InvalidCastException.
	IConvertible.ToDecimal	Converts the value to an equivalent Decimal number.
	IConvertible.ToDouble	Converts the value to an equivalent double-precision floating-point number.
	IConvertible.ToInt16	Converts the value to an equivalent 16-bit signed integer.
	IConvertible.ToInt32	Converts the value to an equivalent 32-bit signed integer.
	IConvertible.ToInt64	Converts the value to an equivalent 64-bit signed integer.
	IConvertible.ToSByte	Converts the value to an equivalent 8-bit signed integer.
	IConvertible.ToSingle	Converts the value to an equivalent single precision floating-point number.
	IConvertible.ToType	Converts the value to an Object of the specified Type with the equivalent value.
	IConvertible.ToUInt16	Converts the value to an equivalent 16-bit unsigned integer.
	IConvertible.ToUInt32	Converts the value to an equivalent 32-bit unsigned integer.
	IConvertible.ToUInt64	Converts the value to an equivalent 64-bit unsigned integer.

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