Boolean Struct

Definition

public value class bool : IComparable, IComparable<bool>, IConvertible, IEquatable<bool>

public value class bool : IComparable, IComparable<bool>, IConvertible, IEquatable<bool>, IParsable<bool>, ISpanParsable<bool>

public value class bool : IComparable, IConvertible

public value class bool : IComparable, IComparable<bool>, IEquatable<bool>

public struct Boolean : IComparable, IComparable<bool>, IConvertible, IEquatable<bool>

public readonly struct Boolean : IComparable, IComparable<bool>, IConvertible, IEquatable<bool>, IParsable<bool>, ISpanParsable<bool>

public readonly struct Boolean : IComparable, IComparable<bool>, IConvertible, IEquatable<bool>

[System.Serializable]
public struct Boolean : IComparable, IConvertible

[System.Serializable]
[System.Runtime.InteropServices.ComVisible(true)]
public struct Boolean : IComparable, IComparable<bool>, IConvertible, IEquatable<bool>

public struct Boolean : IComparable, IComparable<bool>, IEquatable<bool>

type bool = struct
    interface IConvertible

type bool = struct
    interface IConvertible
    interface IParsable<bool>
    interface ISpanParsable<bool>

[<System.Serializable>]
type bool = struct
    interface IConvertible

[<System.Serializable>]
[<System.Runtime.InteropServices.ComVisible(true)>]
type bool = struct
    interface IConvertible

type bool = struct

Public Structure Boolean
Implements IComparable, IComparable(Of Boolean), IConvertible, IEquatable(Of Boolean)

Public Structure Boolean
Implements IComparable, IComparable(Of Boolean), IConvertible, IEquatable(Of Boolean), IParsable(Of Boolean), ISpanParsable(Of Boolean)

Public Structure Boolean
Implements IComparable, IConvertible

Public Structure Boolean
Implements IComparable, IComparable(Of Boolean), IEquatable(Of Boolean)

Inheritance

Object

ValueType

Boolean

Attributes

SerializableAttribute ComVisibleAttribute

Implements

IComparable IComparable<Boolean> IConvertible IEquatable<Boolean> IParsable<Boolean> IParsable<TSelf> ISpanParsable<Boolean>

Remarks

A Boolean instance can have either of two values: true or false.

The Boolean structure provides methods that support the following tasks:

• Converting Boolean values to strings: ToString
• Parsing strings to convert them to Boolean values: Parse and TryParse
• Comparing values: CompareTo and Equals

This article explains these tasks and other usage details.

Format Boolean values

The string representation of a Boolean is either "True" for a true value or "False" for a false value. The string representation of a Boolean value is defined by the read-only TrueString and FalseString fields.

You use the ToString method to convert Boolean values to strings. The Boolean structure includes two ToString overloads: the parameterless ToString() method and the ToString(IFormatProvider) method, which includes a parameter that controls formatting. However, because this parameter is ignored, the two overloads produce identical strings. The ToString(IFormatProvider) method does not support culture-sensitive formatting.

The following example illustrates formatting with the ToString method. Note that the C# and VB examples use the composite formatting feature, while the F# example uses string interpolation. In both cases the ToString method is called implicitly.

using System;

public class Example10
{
   public static void Main()
   {
      bool raining = false;
      bool busLate = true;

      Console.WriteLine($"It is raining: {raining}");
      Console.WriteLine($"The bus is late: {busLate}");
   }
}
// The example displays the following output:
//       It is raining: False
//       The bus is late: True

let raining = false
let busLate = true

printfn $"It is raining: {raining}"
printfn $"The bus is late: {busLate}"

// The example displays the following output:
//       It is raining: False
//       The bus is late: True

Module Example9
    Public Sub Main()
        Dim raining As Boolean = False
        Dim busLate As Boolean = True

        Console.WriteLine("It is raining: {0}", raining)
        Console.WriteLine("The bus is late: {0}", busLate)
    End Sub
End Module
' The example displays the following output:
'       It is raining: False
'       The bus is late: True

Because the Boolean structure can have only two values, it is easy to add custom formatting. For simple custom formatting in which other string literals are substituted for "True" and "False", you can use any conditional evaluation feature supported by your language, such as the conditional operator in C# or the If operator in Visual Basic. The following example uses this technique to format Boolean values as "Yes" and "No" rather than "True" and "False".

using System;

public class Example11
{
    public static void Main()
    {
        bool raining = false;
        bool busLate = true;

        Console.WriteLine($"It is raining: {(raining ? "Yes" : "No")}");
        Console.WriteLine($"The bus is late: {(busLate ? "Yes" : "No")}");
    }
}
// The example displays the following output:
//       It is raining: No
//       The bus is late: Yes

Module Example
   Public Sub Main()
      Dim raining As Boolean = False
      Dim busLate As Boolean = True

      Console.WriteLine("It is raining: {0}", 
                        If(raining, "Yes", "No"))
      Console.WriteLine("The bus is late: {0}", 
                        If(busLate, "Yes", "No"))
   End Sub
End Module
' The example displays the following output:
'       It is raining: No
'       The bus is late: Yes

let raining = false
let busLate = true

printfn $"""It is raining: %s{if raining then "Yes" else "No"}"""
printfn $"""The bus is late: %s{if busLate then "Yes" else "No"}"""

// The example displays the following output:
//       It is raining: No
//       The bus is late: Yes

For more complex custom formatting operations, including culture-sensitive formatting, you can call the String.Format(IFormatProvider, String, Object[]) method and provide an ICustomFormatter implementation. The following example implements the ICustomFormatter and IFormatProvider interfaces to provide culture-sensitive Boolean strings for the English (United States), French (France), and Russian (Russia) cultures.

using System;
using System.Globalization;

public class Example4
{
   public static void Main()
   {
      String[] cultureNames = { "", "en-US", "fr-FR", "ru-RU" };
      foreach (var cultureName in cultureNames) {
         bool value = true;
         CultureInfo culture = CultureInfo.CreateSpecificCulture(cultureName);
         BooleanFormatter formatter = new BooleanFormatter(culture);

         string result = string.Format(formatter, "Value for '{0}': {1}", culture.Name, value);
         Console.WriteLine(result);
      }
   }
}

public class BooleanFormatter : ICustomFormatter, IFormatProvider
{
   private CultureInfo culture;

   public BooleanFormatter() : this(CultureInfo.CurrentCulture)
   { }

   public BooleanFormatter(CultureInfo culture)
   {
      this.culture = culture;
   }

   public Object GetFormat(Type formatType)
   {
      if (formatType == typeof(ICustomFormatter))
         return this;
      else
         return null;
   }

   public string Format(string fmt, Object arg, IFormatProvider formatProvider)
   {
      // Exit if another format provider is used.
      if (! formatProvider.Equals(this)) return null;

      // Exit if the type to be formatted is not a Boolean
      if (! (arg is Boolean)) return null;

      bool value = (bool) arg;
      return culture.Name switch 
     {
         "en-US" => value.ToString(),
         "fr-FR" => value ? "vrai" : "faux",
         "ru-RU" => value ? "верно" : "неверно",
         _  => value.ToString(),
      };
   }
}
// The example displays the following output:
//       Value for '': True
//       Value for 'en-US': True
//       Value for 'fr-FR': vrai
//       Value for 'ru-RU': верно

open System
open System.Globalization

type BooleanFormatter(culture) =
    interface ICustomFormatter with
        member this.Format(_, arg, formatProvider) =
            if formatProvider <> this then null
            else
                match arg with
                | :? bool as value -> 
                    match culture.Name with 
                    | "en-US" -> string arg
                    | "fr-FR" when value -> "vrai"
                    | "fr-FR" -> "faux"
                    | "ru-RU" when value -> "верно"
                    | "ru-RU" -> "неверно"
                    | _ -> string arg
                | _ -> null
    interface IFormatProvider with
        member this.GetFormat(formatType) =
            if formatType = typeof<ICustomFormatter> then this
            else null
    new() = BooleanFormatter CultureInfo.CurrentCulture

let cultureNames = [ ""; "en-US"; "fr-FR"; "ru-RU" ]
for cultureName in cultureNames do
    let value = true
    let culture = CultureInfo.CreateSpecificCulture cultureName 
    let formatter = BooleanFormatter culture

    String.Format(formatter, "Value for '{0}': {1}", culture.Name, value)
    |> printfn "%s"

// The example displays the following output:
//       Value for '': True
//       Value for 'en-US': True
//       Value for 'fr-FR': vrai
//       Value for 'ru-RU': верно

Imports System.Globalization

Module Example4
    Public Sub Main()
        Dim cultureNames() As String = {"", "en-US", "fr-FR", "ru-RU"}
        For Each cultureName In cultureNames
            Dim value As Boolean = True
            Dim culture As CultureInfo = CultureInfo.CreateSpecificCulture(cultureName)
            Dim formatter As New BooleanFormatter(culture)

            Dim result As String = String.Format(formatter, "Value for '{0}': {1}", culture.Name, value)
            Console.WriteLine(result)
        Next
    End Sub
End Module

Public Class BooleanFormatter 
   Implements ICustomFormatter, IFormatProvider
   
   Private culture As CultureInfo
   
   Public Sub New()
      Me.New(CultureInfo.CurrentCulture)
   End Sub
   
   Public Sub New(culture As CultureInfo)
      Me.culture = culture 
   End Sub
   
   Public Function GetFormat(formatType As Type) As Object _
                   Implements IFormatProvider.GetFormat
      If formatType Is GetType(ICustomFormatter) Then
         Return Me
      Else
         Return Nothing
      End If                
   End Function
   
   Public Function Format(fmt As String, arg As Object, 
                          formatProvider As IFormatProvider) As String _
                   Implements ICustomFormatter.Format
      ' Exit if another format provider is used.
      If Not formatProvider.Equals(Me) Then Return Nothing
      
      ' Exit if the type to be formatted is not a Boolean
      If Not TypeOf arg Is Boolean Then Return Nothing
      
      Dim value As Boolean = CBool(arg)
      Select culture.Name
         Case "en-US"
            Return value.ToString()
         Case "fr-FR"
            If value Then
               Return "vrai"
            Else
               Return "faux"
            End If      
         Case "ru-RU"
            If value Then
               Return "верно"
            Else
               Return "неверно"
            End If   
         Case Else
            Return value.ToString()  
      End Select
   End Function
End Class
' The example displays the following output:
'          Value for '': True
'          Value for 'en-US': True
'          Value for 'fr-FR': vrai
'          Value for 'ru-RU': верно

Optionally, you can use resource files to define culture-specific Boolean strings.

Convert to and from Boolean values

The