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Issue with ShowMandatory = true Property for Enum Fields in Business Central

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Posted on by SE-06111435-0

Dear Dynamics Community,

I am currently attempting to use the page property ShowMandatory = true to mark an enum field as required on a page. While this property functions correctly for fields of type Code, it does not appear to have any effect when applied to enum fields.

Is there a known limitation regarding the use of ShowMandatory with enum field types? If so, I would greatly appreciate any suggestions or workarounds to achieve similar functionality for enum fields.

Thank you in advance for your support and guidance.

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Dynamics 365 Business Central

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Teagen Boll 663 on at

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That might be tricky because ShowMandatory is just looking to see if a field isn't blank then displaying a red asterisk.

You could try using the property NotBlank instead and it will also add the red asterisk and also validate the field. You could then try having one value be None like this:

enum 50121 Loyalty
{
Extensible = true;

value(0; None) { }
value(1; Bronze) { }
value(2; Silver) { }
value(3; Gold)
{
Caption = 'Gold Customer';
}
}

Then try using either ShowMandatory or NotBlank to see if that flags it as mandatory/validates the field.

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Gregory Mavrogeorgis 763 on at

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Hi,

Yep—this is (kinda) a limitation. ShowMandatory only shows the red asterisk if a field can be blank. Enums always have a value (default = first member), so nothing to flag.
Easy workaround:

Add a “Not set” enum value (make it the first).

Bind the asterisk to a boolean/expression:

ShowMandatory = (Rec."My Status" = Rec."My Status"::"Not set");

Enforce server-side so users can’t save “Not set”:

if Rec."My Status" = Rec."My Status"::"Not set" then

Error('%1 is required.', FieldCaption("My Status"));

Can’t change the enum? Use a page variable to drive ShowMandatory with your own logic, and keep the table validation.

If you found this helpful please mark it as verified

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Teddy Herryanto (Th... 14,284 Super User 2025 Season 2 on at

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ShowMandatory doesn't work with Enum.

What you can do is set the 0 caption as something like "Must select one".

Then add a code somewhere to validate it, such as OnInsert or OnModify.

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Jainam M. Kothari 15,627 Super User 2025 Season 2 on at

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May this can help : https://github.com/microsoft/AL/issues/4362

https://www.navisionplanet.com/making-fields-mandatory-in-dynamics-365-business-central/

https://yzhums.com/58640/

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Valentin Castravet 31,262 Super User 2025 Season 2 on at

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It can work like this: most enum fields aren’t blank by default, so to use ShowMandatory include a blank option. Set both ShowMandatory and BlankZero on the field.
For example, in the field below I set the enum’s value(0) caption to a single space and then set both ShowMandatory and BlankZero to true:

Valentin Castravet
Work: Zander ERP Services
Blog: Dynamics 365 Business Central Insights
LinkedIn: www.linkedin.com/in/valentin-c-0500a247/

2 people found this reply helpful.

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YUN ZHU 95,309 Super User 2025 Season 2 on at

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Hi, hope the following helps.

Dynamics 365 Business Central: The red asterisk next to a field (mandatory field???)

https://yzhums.com/58640/

Thanks.

ZHU

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OussamaSabbouh 5,078 on at

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Hello,

Yes — ShowMandatory doesn’t highlight enum fields because enums always have a value (their default option).

To mimic required behavior:

Add a blank/“<Select>” value in the enum.

Use StyleExpr or OnValidate to flag or block when it’s still “<Select>”.

Regards,

Oussama Sabbouh

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Aman Kakkar 2,241 on at

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Hi,

You can achieve this via writing below mentioned code snippets.

STEP 01 - Add a blank value at index 0 in your enum definition. This allows the field to appear empty until a valid selection is made.

enum 50010 Test { Extensible = true; value(0; "") { } value(1; Test01) { } value(2; Test02) { } value(3; Test03) { } }

STEP 02 - On your page field, set the following properties:

field("Test Enum"; Rec."Test Enum") { ShowMandatory = true; BlankZero = true; }

Now the enum field will behave like a required field (ShowMandatory = true) — showing the red asterisk and prompting the user to select a valid value other than the blank one.

Do mark as verified if this helps.

Aman K

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Khushbu Rajvi. 20,234 Super User 2025 Season 2 on at

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Dynamics 365 Business Central: ShowMandatory for Enum, Option, and Integer Fields | Business Central Junction 365 Blogs

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