By the end of this chapter you will understand what a Calculate action is and how to use them, and you will have created three Calculate Actionflows in your application.

What is a Calculate Action?

The 

Creating Calculate Actions

1. Click and drag the 

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    icon from the toolbar onto the canvas
2. Enter a name for the Calculate action, then select Create Action
3. In the Calculate Action 

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    on the right, click the 

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    icon in the Output Attributes section to add new attributes

Worked Example

Here's a worked example using the School Data (available from the Learning Centre).

We want to be able to filter the records that can be seen in our School Courses grid. To do this, we will create three Calculate Actionflows. Each Actionflow will populate a string field with a string of text. That text will then be interpreted by a background filter to see if it matches any records for the specified attributes, and will filter the grid accordingly.

Calculate Actions to Initiate Filters

1. Open the Course Management screen where the Actionflow will be initiated from
2. The Filters panel on the left of the screen contains a number of buttons which we will set up so when they are pressed, the School Courses grid is filtered:
   1. All: This will reset the grid to show all records
   2. Maths: This will show only records where the department name is Mathematics
   3. English: This will show only records where the department name is English

Reset Filter

1. Right-click on the  button and choose 

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2. Enter a name for the Actionflow:
   1. Name: All Filter
3. Connect the filter button by selecting Click to Connect
   1. For the input, choose the On Click Action Event, then select Connect Input
4. Click and drag the 

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    icon from the toolbar onto the canvas
5. Enter a name for the Calculate action:
   1. Name: Reset Filter
   2. Select Create Action
6. Click and drag the 

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    icon onto the Reset Filter node to connect the input to the action
7. Click on the Reset Filter node to open its

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    on the right
8. In the Output Attributes section, click the 

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    icon
9. Enter the following details for the new Output Attribute:
   1. Name: pfDept
   2. Type: choose String

   3. Expression: 

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      "All"

      
      

   4. Then 

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10. Under Connections, click 

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     Add
11. In the Add Connection Point window, enter:
    1. Name: Out
    2. Type: choose Output
    3. Select Create Connection Point
12. Click on Click to Connect
13. In the Connect Output window, choose the Course Management form and select Connect Output
14. Close the Mappings window that opens
15. Hover over the Reset Filter calculate node on the canvas and select out
16. A red arrow will attach to your mouse, click on the 

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     icon under Connections
17. The Mappings window will open:
    1. Drag across the Output Attribute, pfDept, into the area on the right to create a corresponding attribute on the output connection point
    2. Press Save
18. Right-click the Out wire, under Connections, and choose

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19. The Mappings window will open:
    1. Select Map by Name
    2. Press Save
20. Close the Actionflow to return to the Course Management screen

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     the screen and press the  button to see the Actionflow in action
    1. We can see that the Actionflow is working because it displays the string, All, in the pfDept String field and all records display in the grid

Maths Filter

Have a go at creating the Actionflow for the  button, with some guidance below.

1. Right-click on the  button and choose 

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2. Enter a name for the Actionflow:
   1. Name: Maths Filter
3. Repeat the same steps as with the All Filter, but make the following changes:
   1. Name the Calculate Action: Maths Filter

   2. When creating a new Output Attribute, the following expression should be used:

      Code Block
      "Mathematics"

      
      

      Tip
      title Why do we use "Mathematics" and not "Maths"?
      We use "Mathematics" because this is the spelling of the Department Name in our data (you can see this on the School Courses grid), therefore the Background Filter is looking to match up the text in the string field with the data name. Where it gets a match, it will filter the grid accordingly. If we use a different spelling or shortening, the filter will not work as expected.

      
      

4. Close the Actionflow to return to the Course Management screen
5. Lock the screen and press the  button to see the Actionflow in action
   1. We can see that the Actionflow is working because it displays the string, Mathematics, in the pfDept String field and just the matching records display in the grid

English Filter

Use the knowledge you have acquired throughout this chapter to independently create the Actionflow for the English filter.