Form Patterns & Screen Guidelines in Dynamics 365 Finance & Operations
Question 42 — Applying standard form patterns for consistent, compliant UI.
Interview Question
Model Answer (Short)
A form pattern is a predefined template that dictates the structure and layout of a form — which containers, groups and controls it should have and how they are arranged. The guideline is that non-custom (standard) form patterns must be applied to all screens, so every form follows the same familiar structure as the standard application. Applying a pattern enforces consistency, accessibility and responsive behaviour, and the system validates the form against the chosen pattern, flagging missing or misplaced controls. You choose the pattern that matches the form type (e.g. Details Master, Simple List, List Page, Dialog) rather than building a custom, pattern-less layout.
Detailed Explanation
What form patterns do
- Define the structure and layout a form should follow.
- The system validates the form against the pattern and flags issues.
- Ensure consistency with the standard application UI.
- Provide built-in responsiveness and accessibility.
The guideline
- Non-custom (standard) patterns must be applied to all screens.
- Choose the pattern that matches the form type.
- Avoid building pattern-less / custom layouts where a standard pattern exists.
- Follow Microsoft's general form guidelines for design.
Common Form Patterns
| Pattern | Typical use |
|---|---|
| Details Master | Maintaining a master record with header and tabs (e.g. customers) |
| Details Master w/ Standard Tabs | Master record with a fixed tab structure |
| Simple List | A single grid of records for lightweight maintenance |
| Simple List & Details | A list plus a details section (list on left, detail on right) |
| List Page | A filterable list with action pane for navigation/selection |
| Dialog | A focused input dialog for parameters/actions |
| Table of Contents | Parameter/setup forms with grouped sections |
Prerequisites (Rule 5)
- Visual Studio with the Dynamics 365 developer tools.
- A custom model / package for your objects.
- A form with its data sources defined before applying a pattern.
- Understanding of the form type so you select the right pattern.
Applying a Pattern (steps)
In the designer
- Right-click the form design node in the designer.
- Choose Apply pattern and select the appropriate standard pattern.
- Add the required containers/controls the pattern expects.
- Resolve any pattern validation warnings shown in the error list.
Example — form control event handler on a patterned form
// Standard patterns still allow custom behaviour via event handlers
[FormControlEventHandler(formControlStr(AbcCustomerDetails, ApproveBtn),
FormControlEventType::Clicked)]
public static void ApproveBtn_OnClicked(FormControl sender, FormControlEventArgs e)
{
FormRun formRun = sender.formRun();
CustTable custTable = formRun.dataSource(formDataSourceStr(AbcCustomerDetails, CustTable)).cursor();
custTable.AbcApproved = NoYes::Yes;
custTable.update();
}Points the interviewer wants to hear
- Form patterns define a form's structure and layout.
- Standard (non-custom) patterns must be applied to all screens.
- The system validates the form against the pattern.
- Patterns ensure consistency, accessibility and responsiveness.
- Pick the pattern that matches the form type (Details Master, List Page, Dialog, etc.).
Likely Follow-up Questions
- Why must standard form patterns be applied to every screen?
- What happens if a form doesn't comply with its selected pattern?
- Which pattern would you use for a filterable list with an action pane?
- Can you still add custom logic to a patterned form?
Key Takeaway
Apply a standard form pattern to every screen and match it to the form type. Patterns enforce a consistent, accessible and responsive UI, and the system validates your form against the chosen pattern — so avoid building custom, pattern-less layouts.