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(10) Entity Events and Business Commands

- Support Ticket Tutorial -​

Create a Change Log​

Business commands are very useful when you want to interact with your data. You can define Entity events to set conditions for when to trigger your commands. This section will create a simple change log to show all of the changes made to the Title of the Support Tickets by users.

1. Create Log Entity​

First, we need to create the entity where we will store all the logs.

  • Type: Ctrl + Shift + C and click Entity
  • Set Name to: Log
  • Set the Display Icon to: File spreadsheet
  • Mark the Create Display Attribute check circle. Type Title Change
  • Click Next
  • Remove the Create page and Detail Page. Keep the List Page
  • Click Finish
    —
  • Go to Data > Entities and click Ticket
  • Click Add Reference
  • Set Name to: Logs
  • Set Type to: Composition
  • Set Referenced to: Log
  • Click Save

2. Update Entity pages​

Next, all logs should show for each entity.

  • Go to UI > Entity Pages and click Ticket Detail
  • Go the Layout Editor, and, near the bottom of the page, click the Add Tab magic wand
  • Select Create Child List Tab. (Make sure that all files are saved so that the proper options will be available.)
  • Select Logs
  • In the lower section of the Layout Editor, click the Logs tab
  • Click Edit Layout
  • Click Data Grid of Log
  • The default setting shows the Columns tab. Log is shown by default. Add Ticket
  • Click OK
    —
  • Go to the General tab
  • Verify that Entity is set to: Log
  • Verify that Data Source is set to:
(ticket, db, ctx) => db.LogSet.Where(x => x.Ticket == ticket)
  • Click OK
  • Click OK
  • Save: Ctrl + S

3. Create Business command​

A command needs to be established to pull the log into the list.

  • Type: Ctrl + Shift + C and in the Business section, select Command
  • Set Name to: Log Title Change
  • Set Type to: Entity Command
  • Set Entity to: Ticket
  • Click Finish
  • Copy and paste the following code:
(ticket, db, ctx) =>
{
  ticket.Logs.Add(new Log()
    {
        TitleChange = "Title changed at: " + DateTime.Now.ToString() + " - New Title: " + (string.IsNullOrEmpty(ticket.Title) ? "no title defined!" : ticket.Title)
      });
}
  • Save: Ctrl + S

4. Create Event Entity​

The trigger for data to be added to the Change Log is when an end user alters the title of a Support Ticket.

  • Type: Ctrl + Shift + C and in the Business section, select Business Events.
  • Set Command to: LogTitleChange (Ticket)
  • Click Finish
    —
    On the Event Triggers page, select the appropriate allocations.
  • Set Entity Ticket to Created

In the Attribute Changes section,

  • Mark Title as Changed
  • Save: Ctrl + S