Export (0) Print
Expand All

Boolean.CompareTo Method (Boolean)

Compares this instance to a specified Boolean object and returns an integer that indicates their relationship to one another.

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

'Declaration
Public Function CompareTo ( _
	value As Boolean _
) As Integer

Parameters

value
Type: System.Boolean

A Boolean object to compare to this instance.

Return Value

Type: System.Int32
A signed integer that indicates the relative values of this instance and value.

Return Value

Condition

Less than zero

This instance is false and value is true.

Zero

This instance and value are equal (either both are true or both are false).

Greater than zero

This instance is true and value is false.

Implements

IComparable(Of T).CompareTo(T)

This method implements the System.IComparable(Of T) interface and performs slightly better than the Boolean.CompareTo method because it does not have to convert the value parameter to an object.

If value has fewer bits (is narrower) than the instance type, some programming languages perform an implicit widening conversion that transforms the value of the parameter into a value with more bits.

For example, suppose the instance type is Int32 and the parameter type is Byte. The Microsoft C# compiler generates instructions to represent the value of the parameter as an Int32 object, then generates a Int32.CompareTo method to compare the Int32 instance and parameter representation.

Consult your programming language's documentation to determine whether its compiler performs implicit widening conversions on numeric types.

The following code example demonstrates generic and nongeneric versions of the CompareTo method for several value and reference types.

' This example demonstrates the generic and non-generic versions of the  
' CompareTo method for several base types. 
' The non-generic version takes a parameter of type Object, while the generic 
' version takes a type-specific parameter, such as Boolean, Int32, or Double. 

Imports System

Class Sample
   Public Shared Sub Main()
      Dim nl As String = Environment.NewLine
      Dim msg As String = _
          "{0}The following is the result of using the generic and non-generic{0}" & _
          "versions of the CompareTo method for several base types:{0}" 

      Dim now As DateTime = DateTime.Now
      ' Time span = 11 days, 22 hours, 33 minutes, 44 seconds 
      Dim tsX As New TimeSpan(11, 22, 33, 44)
      ' Version = 1.2.333.4 
      Dim versX As New Version("1.2.333.4")
      ' Guid = CA761232-ED42-11CE-BACD-00AA0057B223 
      Dim guidX As New Guid("{CA761232-ED42-11CE-BACD-00AA0057B223}")

      Dim a1 As [Boolean] = True,    a2 As [Boolean] = True 
      Dim b1 As [Byte] = 1,          b2 As [Byte] = 1
      Dim c1 As Int16 = -2,          c2 As Int16 = 2
      Dim d1 As Int32 = 3,           d2 As Int32 = 3
      Dim e1 As Int64 = 4,           e2 As Int64 = -4
      Dim f1 As [Decimal] = -5.5D,   f2 As [Decimal] = 5.5D
      Dim g1 As [Single] = 6.6F,     g2 As [Single] = 6.6F
      Dim h1 As [Double] = 7.7,      h2 As [Double] = -7.7
      Dim i1 As [Char] = "A"c,       i2 As [Char] = "A"c
      Dim j1 As String = "abc",      j2 As String = "abc" 
      Dim k1 As DateTime = now,      k2 As DateTime = now
      Dim l1 As TimeSpan = tsX,      l2 As TimeSpan = tsX
      Dim m1 As Version = versX,     m2 As New Version("2.0")
      Dim n1 As Guid = guidX,        n2 As Guid = guidX

      ' The following types are not CLS-compliant. 
      ' SByte, UInt16, UInt32, UInt64

      Console.WriteLine(msg, nl)
      Try 
         ' The second and third Show method call parameters are automatically boxed because 
         ' the second and third Show method declaration arguments expect type Object.

         Show("Boolean:  ", a1, a2, a1.CompareTo(a2), a1.CompareTo(CObj(a2)))
         Show("Byte:     ", b1, b2, b1.CompareTo(b2), b1.CompareTo(CObj(b2)))
         Show("Int16:    ", c1, c2, c1.CompareTo(c2), c1.CompareTo(CObj(c2)))
         Show("Int32:    ", d1, d2, d1.CompareTo(d2), d1.CompareTo(CObj(d2)))
         Show("Int64:    ", e1, e2, e1.CompareTo(e2), e1.CompareTo(CObj(e2)))
         Show("Decimal:  ", f1, f2, f1.CompareTo(f2), f1.CompareTo(CObj(f2)))
         Show("Single:   ", g1, g2, g1.CompareTo(g2), g1.CompareTo(CObj(g2)))
         Show("Double:   ", h1, h2, h1.CompareTo(h2), h1.CompareTo(CObj(h2)))
         Show("Char:     ", i1, i2, i1.CompareTo(i2), i1.CompareTo(CObj(i2)))
         Show("String:   ", j1, j2, j1.CompareTo(j2), j1.CompareTo(CObj(j2)))
         Show("DateTime: ", k1, k2, k1.CompareTo(k2), k1.CompareTo(CObj(k2)))
         Show("TimeSpan: ", l1, l2, l1.CompareTo(l2), l1.CompareTo(CObj(l2)))
         Show("Version:  ", m1, m2, m1.CompareTo(m2), m1.CompareTo(CObj(m2)))
         Show("Guid:     ", n1, n2, n1.CompareTo(n2), n1.CompareTo(CObj(n2)))
         '
         Console.WriteLine("{0}The following types are not CLS-compliant:", nl)
         Console.WriteLine("SByte, UInt16, UInt32, UInt64")

      Catch e As Exception
         Console.WriteLine(e)
      End Try 
   End Sub 'Main

   Public Shared Sub Show(caption As String, var1 As [Object], var2 As [Object], _
                          resultGeneric As Integer, resultNonGeneric As Integer)
      Dim relation As String

      Console.Write(caption)
      If resultGeneric = resultNonGeneric Then 
         If resultGeneric < 0 Then
            relation = "less than" 
         ElseIf resultGeneric > 0 Then
            relation = "greater than" 
         Else
            relation = "equal to" 
         End If
         Console.WriteLine("{0} is {1} {2}", var1, relation, var2)

      ' The following condition will never occur because the generic and non-generic 
      ' CompareTo methods are equivalent. 

      Else
         Console.WriteLine("Generic CompareTo = {0}; non-generic CompareTo = {1}", _
                            resultGeneric, resultNonGeneric)
      End If 
   End Sub 'Show
End Class 'Sample

'This example produces the following results: 

'The following is the result of using the generic and non-generic versions of the 
'CompareTo method for several base types: 

'Boolean:  True is equal to True 
'Byte:     1 is equal to 1 
'Int16:    -2 is less than 2 
'Int32:    3 is equal to 3 
'Int64:    4 is greater than -4 
'Decimal:  -5.5 is less than 5.5 
'Single:   6.6 is equal to 6.6 
'Double:   7.7 is greater than -7.7 
'Char:     A is equal to A 
'String:   abc is equal to abc 
'DateTime: 12/1/2003 5:37:46 PM is equal to 12/1/2003 5:37:46 PM 
'TimeSpan: 11.22:33:44 is equal to 11.22:33:44 
'Version:  1.2.333.4 is less than 2.0 
'Guid:     ca761232-ed42-11ce-bacd-00aa0057b223 is equal to ca761232-ed42-11ce-bacd-00 
'aa0057b223 

'The following types are not CLS-compliant: 
'SByte, UInt16, UInt32, UInt64 
'

.NET Framework

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

.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.

Show:
© 2014 Microsoft