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Guidelines for creating Screen Templates

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  • You should create such Screen Templates that, when used by developers, produce Screens with excellent UX and performance.

    In general, you should:

    • Use public Blocks and UI elements to avoid duplicates in the target module.
    • Enter the metadata to help developers find the Screen Template they need.
    • Create logic that's sufficient for UI.
    • Make your Screen Templates as reusable as possible.

    Test your Screen Templates so they're without errors and warnings. Once developers create a Screen from your Screen Template, they should be able to publish it and do a demo.

    Replace Data guidelines

    The Replace Data feature enables developers to replace the data sources and related labels in a Screen by dragging and dropping an Entity or Attribute. This can accelerate the work of developers or slow them down if the Data Replacement causes many errors that require manual fixing.

    Here are the tips for creating Screen Templates with good support for Data Replacement.


    The main points about using Aggregates:

    • Use Aggregates in elements such as List, TableRecords, Charts, Forms to populate them with data.
    • Don't use the word sample in the Aggregate names, as this might conflict with the performance of the Replace Data algorithm.

    Enable the replacement for non-default Widgets

    If you want to provide the Data Replacement feature in elements other than lists, tables, forms, and charts, add the servicestudio-showRecord attribute to the element and set the attribute to True.

    In Reactive Web App, go to the properties and then under Attributes add servicestudio-showRecord as a new property. Then, set the value to True.


    In Traditional Web App use the Extended Properties pane to add the same attribute.

    Properties pane


    Design Screen Templates in such a way that it's quick to understand how the UI elements and attributes work together, as this makes Screens quicker to troubleshoot.

    Data sources

    You should design the data in Widgets without mixing the local and server sources. The Data Replacement can only replace server data with server data, and local data with local data.


    Use generic names, like Table, List, Form etc. for the Widgets. When there are more identical elements, use something like MainTable and SecondaryTable.

    Widget names


    When designing prompts make them generic and different from the Entity names. For example, use "Search" instead of "Search name or department".

    Sample Data and business logic

    If you are creating Screen Templates specific to cases where you know the data model, it makes sense to implement business logic. Otherwise, target simpler logic that works in generic use cases.


    If you want to protect variables from Data Replacement in, for example, counters, isolated Widgets, search implementations, use local variables with names different from Entity Attributes.

    References and copied content

    You should create a module to centralize your generic logic and reference the elements from it in the Custom Screens Template Module. That way the platform adds only the references to the target module. If you make logic local to the Custom Screen Template module, the developers end up with duplicated content in the target module.

    On the other hand, you should create content local to the Custom Screen Template module if you need that content copied to the target module.

    Custom styles

    Use the OutSystems UI Framework CSS classes or classes from your default Theme. This makes your design consistent and without duplicated CSS in the target modules. Also, if the developers select a Screen Template without a compatible Theme in the target module, they see a message warning them about the incompatibility.

    Preview and testing

    In cases where an element collapses within a branch of the If tool and breaks the preview in the main editor, wrap the element inside a Container. This forces the element to take the full width of the parent Container and fixes the preview.

    Service Studio Preview

    Use a "Work in progress" category, or similar, to let the developers know which Screen Templates are work in progress.

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