Contract.ForAll Method
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| ForAll(Int32, Int32, Predicate<Int32>) |
Determines whether a particular condition is valid for all integers in a specified range. |
| ForAll<T>(IEnumerable<T>, Predicate<T>) |
Determines whether all the elements in a collection exist within a function. |
- Source:
- Contracts.cs
- Source:
- Contracts.cs
- Source:
- Contracts.cs
Determines whether a particular condition is valid for all integers in a specified range.
public:
static bool ForAll(int fromInclusive, int toExclusive, Predicate<int> ^ predicate);C#
public static bool ForAll(int fromInclusive, int toExclusive, Predicate<int> predicate);static member ForAll : int * int * Predicate<int> -> boolPublic Shared Function ForAll (fromInclusive As Integer, toExclusive As Integer, predicate As Predicate(Of Integer)) As BooleanParameters
- fromInclusive
- Int32
The first integer to pass to predicate.
- toExclusive
- Int32
One more than the last integer to pass to predicate.
The function to evaluate for the existence of the integers in the specified range.
Returns
true if predicate returns true for all integers starting from fromInclusive to toExclusive - 1.
Exceptions
predicate is null.
toExclusive is less than fromInclusive.
Examples
The following example demonstrates how to use the ForAll method to determine whether an array has a null element.
C#
using System;
using System.Diagnostics.Contracts;
using System.Collections.Generic;
namespace AssumeEx
{
class Program
{
// Start application with at least two arguments
static void Main(string[] args)
{
args[1] = null;
Contract.Requires(args != null && Contract.ForAll(0, args.Length, i => args[i] != null));
// test the ForAll method. This is only for purpose of demonstrating how ForAll works.
CheckIndexes(args);
Stack<string> numbers = new Stack<string>();
numbers.Push("one");
numbers.Push("two");
numbers.Push(null);
numbers.Push("four");
numbers.Push("five");
Contract.Requires(numbers != null && !Contract.ForAll(numbers, (String x) => x != null));
// test the ForAll generic overload. This is only for purpose of demonstrating how ForAll works.
CheckTypeArray(numbers);
}
private static bool CheckIndexes(string[] args)
{
try
{
if (args != null && !Contract.ForAll(0, args.Length, i => args[i] != null))
throw new ArgumentException("The parameter array has a null element", "args");
return true;
}
catch (ArgumentException e)
{
Console.WriteLine(e.Message);
return false;
}
}
private static bool CheckTypeArray(IEnumerable<String> xs)
{
try
{
if (xs != null && !Contract.ForAll(xs, (String x) => x != null))
throw new ArgumentException("The parameter array has a null element", "indexes");
return true;
}
catch (ArgumentException e)
{
Console.WriteLine(e.Message);
return false;
}
}
}
}
Imports System.Diagnostics.Contracts
Imports System.Collections.Generic
Class Program
' Start application with at least two arguments.
Shared Sub Main(ByVal args() As String)
args(1) = Nothing
Contract.Requires(Not (args Is Nothing) AndAlso Contract.ForAll(args, Function(s) s Is Nothing))
' test the ForAll method. This is only for purpose of demonstrating how ForAll works.
CheckIndexes(args)
Dim numbers As New Stack(Of String)
numbers.Push("one")
numbers.Push("two")
numbers.Push("three")
numbers.Push("four")
numbers.Push("five")
Contract.Requires(Not (numbers Is Nothing) AndAlso Not Contract.ForAll(numbers, Function(s) s Is Nothing))
' test the ForAll generic overload. This is only for purpose of demonstrating how ForAll works.
CheckTypeArray(numbers)
End Sub
Private Shared Function CheckIndexes(ByVal args() As String) As Boolean
Try
If Not (args Is Nothing) AndAlso Not Contract.ForAll(0, args.Length, Function(i) args(i) Is Nothing) Then
Throw New ArgumentException("The parameter array has a null element", "args")
End If
Return True
Catch e As ArgumentException
Console.WriteLine(e.Message)
Return False
End Try
End Function 'CheckIndexes
Private Shared Function CheckTypeArray(ByVal xs As Stack(Of String)) As Boolean
Try
If Not (xs Is Nothing) AndAlso Not Contract.ForAll(xs, Function(s) s Is Nothing) Then
Throw New ArgumentException("The parameter array has a null element", "Stack")
End If
Return True
Catch e As ArgumentException
Console.WriteLine(e.Message)
Return False
End Try
End Function 'CheckTypeArray
End Class
Remarks
The toExclusive parameter is one more than the last integer to facilitate using the length of a range of integers starting at 0. For example, it would be set to 5 for integers 0 through 4.
See also
Applies to
.NET 9 and other versions
| Product | Versions |
|---|---|
| .NET | Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9 |
| .NET Framework | 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1 |
| .NET Standard | 2.0, 2.1 |
| UWP | 10.0 |
- Source:
- Contracts.cs
- Source:
- Contracts.cs
- Source:
- Contracts.cs
Determines whether all the elements in a collection exist within a function.
public:
generic <typename T>
static bool ForAll(System::Collections::Generic::IEnumerable<T> ^ collection, Predicate<T> ^ predicate);C#
public static bool ForAll<T>(System.Collections.Generic.IEnumerable<T> collection, Predicate<T> predicate);static member ForAll : seq<'T> * Predicate<'T> -> boolPublic Shared Function ForAll(Of T) (collection As IEnumerable(Of T), predicate As Predicate(Of T)) As BooleanType Parameters
- T
The type that is contained in collection.
Parameters
- collection
- IEnumerable<T>
The collection from which elements of type T will be drawn to pass to predicate.
- predicate
- Predicate<T>
The function to evaluate for the existence of all the elements in collection.
Returns
true if and only if predicate returns true for all elements of type T in collection.
Exceptions
collection or predicate is null.
Examples
The following example demonstrates how to use the ForAll method to determine whether a collection has a null element.
C#
using System;
using System.Diagnostics.Contracts;
using System.Collections.Generic;
namespace AssumeEx
{
class Program
{
// Start application with at least two arguments
static void Main(string[] args)
{
args[1] = null;
Contract.Requires(args != null && Contract.ForAll(0, args.Length, i => args[i] != null));
// test the ForAll method. This is only for purpose of demonstrating how ForAll works.
CheckIndexes(args);
Stack<string> numbers = new Stack<string>();
numbers.Push("one");
numbers.Push("two");
numbers.Push(null);
numbers.Push("four");
numbers.Push("five");
Contract.Requires(numbers != null && !Contract.ForAll(numbers, (String x) => x != null));
// test the ForAll generic overload. This is only for purpose of demonstrating how ForAll works.
CheckTypeArray(numbers);
}
private static bool CheckIndexes(string[] args)
{
try
{
if (args != null && !Contract.ForAll(0, args.Length, i => args[i] != null))
throw new ArgumentException("The parameter array has a null element", "args");
return true;
}
catch (ArgumentException e)
{
Console.WriteLine(e.Message);
return false;
}
}
private static bool CheckTypeArray(IEnumerable<String> xs)
{
try
{
if (xs != null && !Contract.ForAll(xs, (String x) => x != null))
throw new ArgumentException("The parameter array has a null element", "indexes");
return true;
}
catch (ArgumentException e)
{
Console.WriteLine(e.Message);
return false;
}
}
}
}
Imports System.Diagnostics.Contracts
Imports System.Collections.Generic
Class Program
' Start application with at least two arguments.
Shared Sub Main(ByVal args() As String)
args(1) = Nothing
Contract.Requires(Not (args Is Nothing) AndAlso Contract.ForAll(args, Function(s) s Is Nothing))
' test the ForAll method. This is only for purpose of demonstrating how ForAll works.
CheckIndexes(args)
Dim numbers As New Stack(Of String)
numbers.Push("one")
numbers.Push("two")
numbers.Push("three")
numbers.Push("four")
numbers.Push("five")
Contract.Requires(Not (numbers Is Nothing) AndAlso Not Contract.ForAll(numbers, Function(s) s Is Nothing))
' test the ForAll generic overload. This is only for purpose of demonstrating how ForAll works.
CheckTypeArray(numbers)
End Sub
Private Shared Function CheckIndexes(ByVal args() As String) As Boolean
Try
If Not (args Is Nothing) AndAlso Not Contract.ForAll(0, args.Length, Function(i) args(i) Is Nothing) Then
Throw New ArgumentException("The parameter array has a null element", "args")
End If
Return True
Catch e As ArgumentException
Console.WriteLine(e.Message)
Return False
End Try
End Function 'CheckIndexes
Private Shared Function CheckTypeArray(ByVal xs As Stack(Of String)) As Boolean
Try
If Not (xs Is Nothing) AndAlso Not Contract.ForAll(xs, Function(s) s Is Nothing) Then
Throw New ArgumentException("The parameter array has a null element", "Stack")
End If
Return True
Catch e As ArgumentException
Console.WriteLine(e.Message)
Return False
End Try
End Function 'CheckTypeArray
End Class
See also
Applies to
.NET 9 and other versions
| Product | Versions |
|---|---|
| .NET | Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9 |
| .NET Framework | 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1 |
| .NET Standard | 2.0, 2.1 |
| UWP | 10.0 |
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