Timeouts in Visual Basic .NET

Timeouts are important for programs that connect to external resources or that otherwise need to bound execution time. Implementing timeouts in Visual Basic .NET is straightforward using Tasks and cancellation tokens.

Imports System
Imports System.Threading
Imports System.Threading.Tasks

Module Program
    Sub Main()
        ' For our example, suppose we're executing an external
        ' call that returns its result after 2 seconds.
        ' We'll use a Task to simulate this operation.
        Dim task1 = Task.Run(Async Function()
                                 Await Task.Delay(2000)
                                 Return "result 1"
                             End Function)

        ' Here we implement a timeout using Task.WhenAny and Task.Delay.
        ' We'll wait for either the task to complete or a 1-second timeout.
        Dim timeoutTask = Task.Delay(1000)
        Dim completedTask = Task.WhenAny(task1, timeoutTask).Result

        If completedTask Is task1 Then
            Console.WriteLine(task1.Result)
        Else
            Console.WriteLine("timeout 1")
        End If

        ' If we allow a longer timeout of 3 seconds, then the task
        ' will succeed and we'll print the result.
        Dim task2 = Task.Run(Async Function()
                                 Await Task.Delay(2000)
                                 Return "result 2"
                             End Function)

        timeoutTask = Task.Delay(3000)
        completedTask = Task.WhenAny(task2, timeoutTask).Result

        If completedTask Is task2 Then
            Console.WriteLine(task2.Result)
        Else
            Console.WriteLine("timeout 2")
        End If
    End Sub
End Module

Running this program shows the first operation timing out and the second succeeding.

$ dotnet run
timeout 1
result 2

In this Visual Basic .NET version:

We use Task.Run to create asynchronous operations that simulate long-running tasks.
Instead of channels, we use Task objects to represent our asynchronous operations.
We implement timeouts using Task.WhenAny in combination with Task.Delay. This allows us to race between the actual task and a delay representing our timeout.
We use If statements to check which task completed first (the actual task or the timeout task) and act accordingly.
The Async and Await keywords are used to handle asynchronous operations in a more readable manner.

This approach provides similar functionality to the original example, allowing you to implement timeouts for long-running operations in Visual Basic .NET.

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Non Blocking Channel Operations in Visual Basic .NET

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Timeouts in Visual Basic .NET