Power Apps
Variables:
Microsoft Docs "PowerApps and Excel both automatically recalculate formulas as the input data changes".
- Contextual variables - scoped at a screen level
- Global variables - scoped app level
Fx> Set(MyUniqueClientNo, 12)
Functions:
Fx> UpdateContext({MyTimesheetId: 34})
Tip from Shane Young: Note the setting variable may be the reference, so for a control use:
Fx>
UpdateContext({MyTimesheetId: txtTimesheetId.Text}) not
Fx>
UpdateContext({MyTimesheetId: txtTimesheetId.Text}) unless you want the context to float
Pass a variable to another screen use the Navigate overload,
OnSelect property of a button
Fx>
Navigate(Screen2, ScreenTransition.None, {TSvar: MyTimesheetId}
MyTimeSheet Id is a contextual variable
If Statement:
Fx>
If(MyUniqueClientNo = 12, lblAns.text = 'yes', lblAns.text = 'No')
Environments: - Power Platform allows you to create multiple environments, each environment is connected to you AAD tenant.
- Policies can be applied to prevent DLP against all environments or specific environments.
- Use Environments for DTAP, business units, or Extranet vs Intranet.
- Updated June 2022: Environments can be of type: Default (don't use and rename), Developer, Trial, Sandbox or Production.
- Each Power App environment can have no CDS/Datavserse or a single CDS/Dataverse connect.
Manged vs Un-Managed Solutions:
Solution are useful for packaging and moving assets between environments or tenants. Manged restricts who can edit the applications in the solution. I like to keep each solution with a single app in it. On large projects, it's a good idea to keep environment variables, custom connectors, cloud flows, apps in separate solutions. It makes it easier to deploy pieces.
Managed Environments:
Don't mix up with Managed solutions as I did recently. Managed environments allow for a host to control all the environments. You also should use a dedicated host production environments with Dataverse database to control all the environments. You need to install solution on the host. Managed environment have no correlation to managed solutions. You need managed environments is you are going to use Power Platforms simple ALM for App deployment.
ALM:
Power Apps has it's own source control and you can manually export and import entire projects "Export package" not connections are not export as part of the package. Solutions are the best way to move code between environments. It's a good idea to use environment variables Get ADO, more secure, better tooling using solutions over manual exporting code using packages.
Power Apps Build Tools allows for ADO/DevOps integration generally using solutions to deploy. At a minimum you should have your own dev env (Sandbox or Developer type), a test (Sandbox type) and production (production type env) for any serious app you build.
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| Add "Power Platform Tools" |
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| Example Power Platform ALM deployment using DevOps - 5 environments |
Update Jan 2022:
Solutions are used to in Power Apps to package and move code and resources such as flows, env variables, canvas apps, Dataverse tables between environments. It's a good idea to not use the default environment as everyone has access to the environment. The DTAP around ALM can get pretty complex and I like to keep it fairly simple. Connectors can get nasty in packaging. ADO using AppBuild Tools makes for a good CI/CD solution for Power Apps.
Environment variables are a great way to manage configuration, they can also easily be configure in the pipelines to replace with the appropriate values. Tip: Don't ever set the current value in an env var it get carried thru to the next DTAP env. Also env vars support Azure Key Vault, use it for secrets.
Custom Connectors and getting Connection References correct when using managed environments to deploy code need to use environment variables so they can easily be set for each environment using CI/CD. It's a good idea to create connections in solutions and use a dedicate Owner account.
Connection references in solutions - Power Apps | Microsoft Learn
Have a:
- Dev environment that is of the "sandbox" type. Have an un-managed solution that will act as your base canvas app for all new Power Apps. When you export the solution remember to export as a managed solution and ensure environment variables are emptied before publishing the export. Good place to backup to a repository such as TFS Azure DevOps/Git.
- Test env of the type "production" or "sandbox". Only allow managed solutions to be deployed. Watch out for custom connectors, I can't get them to deploy correctly in solutions.
- Prd env must be of type "production".
Manual ALM i.e. Use PowerApps to store Dev versions, Exporting solutions and unpacking managed solutions into UAT and production. Manual ALM is good even manually moving the applications by hand is simple and safe. There are backups and manual backups to avoid a source code repository. I also like the testing framework in Power Apps. Using the build tools getting full ALM/CI/CD it is easy to then move your Power Platform into a higher ALM CI/CD level using the Power Platform Build tools, DevOps, and PowerShell cmds.
Licencing:
Updated: Power Apps Licencing Summary as of 30 December 2019
"To run standalone apps, guest users need the same license as users in your tenant." Microsoft Docs.
- PowerApps using AAD B2B user (both members and guest) using standalone Power Apps shall require the Power Apps licence (not necessarily Portal Apps). Steps to Share Power Apps with Guests.
- SharePoint user interacting with a Power Apps form on a SharePoint list do not require a Power Apps licence.
Coding Standards for Power Apps:
-
Microsoft provide a whitepaper as a suggestion for using naming/coding standards.
- Controls and variables should use prefixed Camel case e.g. txtContactEmail
- Data sources use Pascal Case e.g. ContactUsers
- Screen must be Full names e.g. Edit Contact User Screen as they are read as named by screen readers like JAWS and Microsoft reader.
- Prefix controls and collections (Label is lbl, Textbox is txt, Button is btn, Collection is col, drop down lists are ddl, Form is frm, Group is grp, Gallery is gal, Icon is ico, Images are img, Table is tbl. I also prefix my components with com.
- Variable naming is: gbl for Global and context variables are var
- Use Containers for layout and groups for control aggregation.
- Use TabIndex so keyboard navigation makes sense. Use the AccessibleLable over HintText. Ensure colour contracts and use the approved colour templates stored in global variables. All fonts, sizing and colouring must come from global variables so the app can be easily changed. Use the App Checked and complete all identified accessibility issues/concerns. Test on actual devices and use screen readers.
- Ensure App Insights is setup, capture and log errors, also use the monitoring (maybe not in production).
:
Build responsive website using CDS. Allow anonymous access or implement multiple Identity Providers (IdP) such as AAD B2C, AAD, Google+, LinkedIn.
Updated: 28 July 2018:
Common Data Service (CDS): Comes from Dynamics CRM Sales, pretty much used like CT's in SharePoint.
- Based on Azure SQL & uses CosmosDB with a nice API that support REST/ODatav4;
- Has Row, field RBAC and uses AAD for authentication;
- Allows Power BI, Power Apps (previously labeled as PowerApps) & Flow (Power Automate - new name since Ignite 2019) to work with CDS (renamed to Dataverse);
- Use Power Query to Import data easily or data flows
- Multiple data source such as SQL Server, Cosmos, files, Excel, Search, 3rd parties such as SAP.
- CDS is not part of the O365 licencing (including E5), you need to get a PowerApps P1 or P2 (Now Power Apps for Users as licencing changed circa Oct 2019). Note Power Apps licencing included with O365 is extremely limited and for instance does not cover CDS;
- One Power Platform Environment ties to one CDS/Dataverse database
- Any type of data; any type of app.
- Easy to use; secure.
https://docs.microsoft.com/en-us/powerapps/maker/common-data-service/data-platform-intro
Examples:
Insert or Update using Patch to CDS:
Patch(
Vote,
Defaults('Employee Sentiment'),
{
userid: UserID,
vote: ThisItem.Vote,
votedate: Now()
}
);
Select from CDS:
UpdateContext( { locVotes: LookUp('Vote', votedate = <date>) });
Tip: XrmToolBox is a fantastic tool. Multiple contributors have added to the client application, there are so many useful features for instance FetchXMLBuilder allows you to query the Dataverse tables.
Power Automate
Updated 11 December 2019:
Microsoft Power Automate (previously called Microsoft Flow, is an user friendly workflow tool/service): Simple workflow engine sitting on Azure Logic App.
Basic business process flows are:
- Automated Flows - used when event/status change e.g. CDS row status changes
- Button Flow/Instant Flow - Events such as a click triggers the flow;
- Scheduled Flow - in effect timer jobs;
- Business Process Flow - ensures users enter data consistently (think Windows Presentation Framework) & follows the same steps every time; and
- UI Flow (preview) - Provides RPA capabilities;
https://docs.microsoft.com/en-us/power-automate/get-started-logic-flow
Building Blocks for Power Automation are:
- Trigger - what starts the workflow, can be manual trigger or an automated trigger
- Actions - ,
- Conditions,
- Data operations,
- Expressions - basic operations like adding two numbers together, making a string upper case, and
- Flow Type - see the 5 flow types above.
Display directions using Map on a Image control in PowerApps:
https://dev.virtualearth.net/REST/v1/Imagery/Map/road/Routes/driving?waypoint.1=51.525503,-0.0822229&waypoint.2=SE9%4PN&mapSize=600,300&key=<key>
https://dev.virtualearth.net/REST/v1/Imagery/Map/road/Routes/driving?waypoint.1=" & EncodeUrl(txtDriverLocation.Text) & "&waypoint.2=" & EncodeUrl(txtDriverLocation.Text) & "&mapSize=600,300&key=AsR555key
