Task Scheduler

Lothar Perr

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18 Apr 2015CPOL2 min read

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A simple structured native task scheduler

Introduction

Task Scheduler is a class that schedules and automatically fires events at a time you specify. All important triggers are available: OnlyOneTime, Daily, Weekly and Monthly.

So why another Task Scheduler?

We need for one of our projects a scheduler that

Can check a date or show all dates on which a trigger will fire. (See the demo - button "Show List")
We need to schedule tasks not only daily, weekly,... we need a combination of them. e.g. every Wednesday (weekly trigger) plus every last day in a month (monthly trigger)

Update 1: Version 1.1

Added date formatting during serialization/deserialization
Fixed issue in TriggerItem.FromXML()

Update 2: Version 1.2

Now using System.Timers.Timer instead of System.Windows.Forms.Timer
Minor changes in XML serialization
Demo now includes a Windows-Service with full service control (start/stop/install/uninstall)
TriggerItemCollection support now serialization / deserialization
Bug fixes

Features

Simple structure and easy to use
Possible triggers: OneTimeOnly, Daily, Weekly and Monthly
Monthly trigger: DayOfMonth and Weekday
Collection of TriggerItems
Next Trigger-Date/Time information
Check if a TriggerItem will fire on a certain date CheckDate(DateTime date)
Combine different triggers in one item. (e.g. every Friday plus every last day in a month)
If there is an overlap the Trigger will fire only one time
Save and restore TriggerItems to and from XML

Settings

Field	Description
`StartDate`	Specifies the first date on which the trigger will fire
`EndDate`	Specifies the last date on which the trigger will fire
`TriggerTime`	Specifies the time on which the trigger will fire
`Enabled`	Enable / disable the trigger
`TriggerSettings`	Set the appropriate trigger-dates as described below

TriggerItem.TriggerSettings Overview:

To activate a specific date just set the appropriate flag(s):

// Activate Sunday on weekly trigger.
triggerItem.TriggerSettings.Weekly.DaysOfWeek[(int)DayOfWeek.Sunday] = true;

// Activate last Friday in January and February
triggerItem.TriggerSettings.Monthly.Month[(int)TaskScheduler.MonthOfTheYeay.January] = 
    true; 
triggerItem.TriggerSettings.Monthly.Month[(int)TaskScheduler.MonthOfTheYeay.February] = 
    true; 
triggerItem.TriggerSettings.Monthly.DaysOfMonth[(int)TaskScheduler.DayOccurrence.Last] =
    true; 
triggerItem.TriggerSettings.Monthly.WeekDay[(int)DayOfWeek.Sunday] = true;

Using TaskScheduler and TriggerItems

Create a new instance of TaskScheduler.

// Create the TaskScheduler
TaskScheduler _taskScheduler = new TaskScheduler();

// Set the synchronizing object to get trigger events within the main thread.
// Important if you're using Windows Forms
_taskScheduler.SynchronizingObject = this;

Create a new Trigger-Item. Set start and end date + trigger time and if you like a tag.

TaskScheduler.TriggerItem triggerItem = new TaskScheduler.TriggerItem();
triggerItem.Tag = textBoxlabelOneTimeOnlyTag.Text;
triggerItem.StartDate = dateTimePickerStartDate.Value;
triggerItem.EndDate = dateTimePickerEndDate.Value;
triggerItem.TriggerTime = dateTimePickerTriggerTime.Value;
// And the trigger-Event :)
triggerItem.OnTrigger += new TaskScheduler.TriggerItem.OnTriggerEventHandler(
    triggerItem_OnTrigger);

Settings for "OneTimeOnly"

TriggerItem.TriggerSettings.OneTimeOnly.Active = checkBoxOneTimeOnlyActive.Checked;
triggerItem.TriggerSettings.OneTimeOnly.Date = 
    dateTimePickerOneTimeOnlyDay.Value.Date;

Settings for "Daily"

triggerItem.TriggerSettings.Daily.Interval = (ushort)numericUpDownDaily.Value;

Settings for "Weekly"

for (byte day = 0; day < 7; day++) // Set the active Days
triggerItem.TriggerSettings.Weekly.DaysOfWeek[day] = 
    checkedListBoxWeeklyDays.GetItemChecked(day);

Settings for "Monthly"

for (byte month = 0; month < 12; month++) // Set the active Months
    triggerItem.TriggerSettings.Monthly.Month[month] = 
    checkedListBoxMonthlyMonths.GetItemChecked(month);

// Set the active Days (0..30 = Days, 31=last Day) for monthly trigger
for (byte day = 0; day < 32; day++)
    triggerItem.TriggerSettings.Monthly.DaysOfMonth[day] = 
    checkedListBoxMonthlyDays.GetItemChecked(day);

// Set the active weekNumber and DayOfWeek
// e.g the first monday, or the last friday...
// 0..4: first, second, third, fourth or last week

for (byte weekNumber = 0; weekNumber < 5; weekNumber++)     
    triggerItem.TriggerSettings.Monthly.WeekDay.WeekNumber[weekNumber] = 
    checkedListBoxMonthlyWeekNumber.GetItemChecked(weekNumber);
for (byte day = 0; day < 7; day++)
    triggerItem.TriggerSettings.Monthly.WeekDay.DayOfWeek[day] = 
    checkedListBoxMonthlyWeekDay.GetItemChecked(day);

Add the trigger to the Collection and enable the Scheduler

triggerItem.Enabled = true; // Set the Item-Active - State
_taskScheduler.AddTrigger(item); // Add the trigger to List
_taskScheduler.Enabled = true; // Start the Scheduler

Disclaimer

THE SOFTWARE AND THE ACCOMPANYING FILES ARE DISTRIBUTED "AS IS" AND WITHOUT ANY WARRANTIES WHETHER EXPRESSED OR IMPLIED. NO REPONSIBILITIES FOR POSSIBLE DAMAGES OR EVEN FUNCTIONALITY CAN BE TAKEN. THE USER MUST ASSUME THE ENTIRE RISK OF USING THIS SOFTWARE.

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Written By

Lothar Perr

p++ Datentechnik GmbH

Germany

This member has not yet provided a Biography. Assume it's interesting and varied, and probably something to do with programming.

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