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Using Power Fx with commands

  • Article

This article covers aspects of Power Fx that are specific to commanding. Many other functions that are in use today within canvas apps can also be used. Keep in mind there are differences because commanding is for model-driven apps.

  • All existing dataflow functions are supported. What are dataflows?
  • Imperative functions that work with data are supported.
  • Imperative functions for simple Confirm and Notify are supported.
  • For a list of functions not supported, go to Functions not supported.

Note

Publishing Power Fx commands may take a few minutes. It might not be obvious that background operations are still running even after the publish operation appears to have completed. You may need to wait a few minutes after publishing, then refresh the app to see your changes reflected. This typically takes longer the first time a Power Fx based command is published for an app.

OnSelect

Defines the logic that is executed when the button is selected within the app.

Visible

Defines logic for hiding or showing the button when running the app.

To define visibility logic, select the command. Then select Visibility on the right command properties pane and choose Show on condition from formula. You can select Visible on the left of the formula bar then write a Power Fx expression using the formula bar.

Selected property

Field Type Description
Item Record of DataSource One of the records selected from the DataSource.
AllItems Table of records from the DataSource All of the records selected from the DataSource.
State Enum State of the selected control. Edit (=0), New (=1), View (=2)
Unsaved Boolean Returns true if Selected or SelectedItems have unsaved changes. Otherwise returns false. Always returns false if AutoSave is set to true (default option) within the command component library.
  • The Selected property is provided by the host of the command.
  • Item and AllItems names are somewhat consistent with the ComboBox control and Gallery control, but this is a new pattern.
  • If there's no record selected, Item returns Blank (IsBlank returns true) and AllItems returns an empty table (IsEmpty returns true).
  • Null DataSource for record references (polymorphic record types). Generic functions can be called, such as Save or IsType/AsType can be used.
  • Item is always blank if SelectionMax <> 1. This prevents writing formulas to just one item and not scaling to more than one.

AutoSave

  • Many JavaScript commands start by saving the form buffer. This is because it makes the rest of the code easier to work with.
  • By default, the form buffer is saved on behalf of the app maker.
    • The form is saved before the command is initiated.
    • Any problems that occur during the save operation are dealt with in the form's UI.

Patch function

Patch (update) the current selected record

Patch(Accounts, Self.Selected.Item, {'Account Name': "Changed Account name"})

Note

If the related table is not already in the command component library you'll need to open it in canvas studio and add the data source there.

Patch(Tasks,Defaults(Tasks),{Regarding:Self.Selected.Item},{Subject:"Subject of the Task"})

Check and edit a date property

If(Self.Selected.Item.'Last Date Included in Campaign'>DateAdd(Now(),-3), Patch(Accounts,Self.Selected.Item,{'Last Date Included in Campaign':Date(2021,10,19)}))

Visible property: Only show the command if one or more records is selected in a grid view

CountRows(Self.Selected.AllItems) > 0

Control visibility based on record data

//Button will be visible for accounts with Account Rating > 20
Self.Selected.Item.'Account Rating'>20

Note

For additional options, see the client API reference to use JavaScript. More information: navigateTo (Client API reference)

Navigate to a custom page

To navigate to a custom canvas page within a model-driven app, pass the page name as the first argument.

Navigate( myCustomPage )

To navigate to the default view of the table, pass the table name as the first argument.

Navigate( Accounts )

To navigate to a specific system view of the table, pass the table's Views enum.

Navigate( 'Accounts (Views)'.'My Active Accounts' )

To navigate to the default form of the table, pass the record as the first argument.

Navigate( Gallery1.Selected )

To navigate to the default form of the table, pass a Dataverse record created from the Defaults function. This opens the default form with the record as a new record. The Defaults function takes the table name to create the record.

Navigate( Defaults( Accounts ) )

Optimize the user experience with data source and record information

Use the DataSourceInfo function and RecordInfo function to optimize the user experience with information about the data being displayed and manipulated.

For example, use RecordInfo to determine if the current user has permission to modify a record and appropriately show or hide an "Edit" button using its Visible property:

EditButton.Visible = 
   RecordInfo( Gallery1.Selected, RecordInfo.EditPermission )

For example, use DataSourceInfo to determine if the current user has permission to create a record and appropriately show or hide a "Create" button using its Visible property:

CreateButton.Visible = 
   DataSourceInfo( Accounts, DataSourceInfo.CreatePermission )

Ask for confirmation before taking action

Use the Confirm function to display a dialog box on top of the current screen.

Notify( Confirm( "Are you sure?", 
                 { ConfirmButton: "Yes", CancelButton: "No" } 
        ) 
)

Displays a notification true if the Yes button is pressed, and a notification false if the No button is pressed.

Notify the user

A notification can be shown to app users by calling the Notify function.

Note

NotificationType.Success is not currently supported and will result in an informational notification type.

Notify( "Model-driven app notification message" )

Other examples

Launch a URL

Launch("https://www.bing.com");

Access 1:N property

Self.Selected.Item.'Recurring Appointments'

Self.Selected.Item.'Parent Account'.'Account Name'="parent"

Functions not supported

The following Power Fx functions are currently not supported with commanding in model-driven apps.

  • Back()
  • Clear()
  • Collect()
  • Copy()
  • Disable()
  • Enable()
  • Exit()
  • InvokeControl()
  • Language()
  • LoadData()
  • Param()
  • ReadNFC()
  • RequestHide()
  • ResetForm()
  • Revert()
  • SaveData()
  • ScanBarcode()
  • Set()
  • SubmitForm()
  • UpdateContext()
  • User()
  • ViewForm()

Enums not supported

  • Align
  • AlignInContainer
  • BarcodeType
  • BorderStyle
  • Color
  • Direction
  • DisplayMode
  • Font
  • FontWeight
  • FormPattern
  • GridStyle
  • ImagePosition
  • ImageRotation
  • LabelPosition
  • Layout
  • LayoutAlignItems
  • LayoutDirection
  • LayoutJustifyContent
  • LayoutMode
  • LayoutOverflow
  • ListItemTemplate
  • MapStyle
  • Overflow
  • PDFPasswordState
  • PenMode
  • RemoveFlags
  • ScreenTransition
  • TeamsTheme
  • TextFormat
  • TextMode
  • TextPosition
  • Themes
  • Transition
  • VerticalAlign
  • VirtualKeyboardMode
  • Zoom

Other unsupported areas

  • Acceleration
  • App
  • Compass
  • Connection
  • Dataverse file type columns
  • Environment
  • Host
  • Layout
  • Location
  • ScreenSize

See also

Understand behavioral formulas

Formula reference

Overview of Power Fx