Few months ago, I wrote a blog post about how to run code daily at a specific time. I didn't know that the post will be the most viewed post on my blog. Also, there were several questions how to implement the complete example. So today, I have decided to write another post, and extend my previous post in order to answer these questions as well as to generalize this subject into a cool demo called Scheduler DEMO.
The post is presenting simple Windows Forms application which calls a method for every minute, day, week, month or year. Also, the demo shows how to cancel the scheduler at any time.
The picture above shows a simple Windows Forms application with two numeric controls in which you can set starting hour and minute for the scheduler. Next, there is a button Start to activate timer for running code, as well as Cancel button to cancel the scheduler. When the time comes, the application writes the message on the Scheduler Log.
Implementation of the Scheduler
Scheduler is started by clicking the Start button which is implemented with the following code:
private void startBtn_Click(object sender, EventArgs e)
{
int hour = (int)numHours.Value;
int minutes = (int)numMins.Value;
var dateNow = DateTime.Now;
var date = new DateTime(dateNow.Year, dateNow.Month, dateNow.Day, hour, minutes, 0);
listBox1.Items.Add("**********Scheduler has been started!*****");
var nextDateValue=getNextDate(date,getScheduler());
runCodeAt(nextDateValue, getScheduler());
}
When the time is defined, then the runCodeAt
method is called which implementation can be like the following:
private void runCodeAt(DateTime date,Scheduler scheduler )
{
m_ctSource = new CancellationTokenSource();
var dateNow = DateTime.Now;
TimeSpan ts;
if (date > dateNow)
ts = date - dateNow;
else
{
date = getNextDate(date, scheduler);
ts = date - dateNow;
}
prepareControlForStart();
Task.Delay(ts).ContinueWith((x) =>
{
methodToCall(date);
runCodeAt(getNextDate(date, scheduler), scheduler);
},m_ctSource.Token);
}
The method above creates the cancelationToken
needed for cancel the scheduler, calculate timeSpan
– total waiting time, then when the time comes, call the method methodToCall
and calculate the next time for running the scheduler.
This demo also shows how to wait for a certain amount of time without blocking the UI thread.
The full demo code can be found on OneDrive.
Bahrudin Hrnjica holds a Ph.D. degree in Technical Science/Engineering from University in Bihać.
Besides teaching at University, he is in the software industry for more than two decades, focusing on development technologies e.g. .NET, Visual Studio, Desktop/Web/Cloud solutions.
He works on the development and application of different ML algorithms. In the development of ML-oriented solutions and modeling, he has more than 10 years of experience. His field of interest is also the development of predictive models with the ML.NET and Keras, but also actively develop two ML-based .NET open source projects: GPdotNET-genetic programming tool and ANNdotNET - deep learning tool on .NET platform. He works in multidisciplinary teams with the mission of optimizing and selecting the ML algorithms to build ML models.
He is the author of several books, and many online articles, writes a blog at http://bhrnjica.net, regularly holds lectures at local and regional conferences, User groups and Code Camp gatherings, and is also the founder of the Bihac Developer Meetup Group. Microsoft recognizes his work and awarded him with the prestigious Microsoft MVP title for the first time in 2011, which he still holds today.