Observable.Generate<TState, TResult> Method (TState, Func<TState, Boolean>, Func<TState, TState>, Func<TState, TResult>, Func<TState, TimeSpan>, IScheduler)
Generates an observable sequence by iterating a state from an initial state until the condition fails.
Namespace: System.Reactive.Linq
Assembly: System.Reactive (in System.Reactive.dll)
Syntax
'Declaration
Public Shared Function Generate(Of TState, TResult) ( _
initialState As TState, _
condition As Func(Of TState, Boolean), _
iterate As Func(Of TState, TState), _
resultSelector As Func(Of TState, TResult), _
timeSelector As Func(Of TState, TimeSpan), _
scheduler As IScheduler _
) As IObservable(Of TResult)
'Usage
Dim initialState As TState
Dim condition As Func(Of TState, Boolean)
Dim iterate As Func(Of TState, TState)
Dim resultSelector As Func(Of TState, TResult)
Dim timeSelector As Func(Of TState, TimeSpan)
Dim scheduler As IScheduler
Dim returnValue As IObservable(Of TResult)
returnValue = Observable.Generate(initialState, _
condition, iterate, resultSelector, _
timeSelector, scheduler)
public static IObservable<TResult> Generate<TState, TResult>(
TState initialState,
Func<TState, bool> condition,
Func<TState, TState> iterate,
Func<TState, TResult> resultSelector,
Func<TState, TimeSpan> timeSelector,
IScheduler scheduler
)
public:
generic<typename TState, typename TResult>
static IObservable<TResult>^ Generate(
TState initialState,
Func<TState, bool>^ condition,
Func<TState, TState>^ iterate,
Func<TState, TResult>^ resultSelector,
Func<TState, TimeSpan>^ timeSelector,
IScheduler^ scheduler
)
static member Generate :
initialState:'TState *
condition:Func<'TState, bool> *
iterate:Func<'TState, 'TState> *
resultSelector:Func<'TState, 'TResult> *
timeSelector:Func<'TState, TimeSpan> *
scheduler:IScheduler -> IObservable<'TResult>
JScript does not support generic types and methods.
Type Parameters
- TState
The type of state.
- TResult
The type of result.
Parameters
- initialState
Type: TState
The initial state.
- condition
Type: System.Func<TState, Boolean>
The condition to terminate generation.
- iterate
Type: System.Func<TState, TState>
The iteration step function.
- resultSelector
Type: System.Func<TState, TResult>
The selector function for results produced in the sequence.
- timeSelector
Type: System.Func<TState, TimeSpan>
The time selector function to control the speed of values being produced each iteration.
- scheduler
Type: System.Reactive.Concurrency.IScheduler
The scheduler on which to run the generator loop.
Return Value
Type: System.IObservable<TResult>
The generated sequence.
Remarks
The Generate operator generates a sequence of the type TState by applying the iterate function to initialState until the condition function returns false for the current state. The resultSelector function is run for each state to generate each item in the resulting sequence.
Examples
This code example uses the Generate operator to generate a sequence of the integers that are perfect squares less than 1000.
using System;
using System.Reactive.Concurrency;
using System.Reactive.Linq;
namespace Example
{
class Program
{
static void Main()
{
//*********************************************************************************************//
//*** Generate a sequence of integers which are the perfect squares that are less than 100. ***//
//*********************************************************************************************//
var obs = Observable.Generate(1, // Initial state value. Starting with 1.
x => x * x < 1000, // Terminate generation when false (the integer squared is not less than 1000).
x => x + 1, // Iteration step function updates the state returning the new state. In this case state is incremented by 1.
x => x * x, // Selector function determines the next resulting value in the sequence. The state of type in is squared.
x => TimeSpan.FromSeconds(1), // Each item in the sequence delayed by 1 sec.
Scheduler.ThreadPool); // The ThreadPool scheduler runs the generation on a thread pool thread instead of the main thread.
using (IDisposable handle = obs.Subscribe(x => Console.WriteLine(x)))
{
Console.WriteLine("Press ENTER to exit...\n");
Console.ReadLine();
}
}
}
}
The following output was generated with the code example.
Press ENTER to exit...
1
4
9
16
25
36
49
64
81
100
121
144
169
196
225
256
289
324
361
400
441
484
529
576
625
676
729
784
841
900
961