Prevent submission of Sharepoint custom form

[U_Idigoras]

Hi,

I've been working on a custom Sharepoint form for my company and I'm stuck. They want to add a checkbox with the usual "I've read and accept the terms" and the form can't be submitted if that checkbox isn't checked.

The problem is, because it's a custom Sharepoint form and not a PowerApps app, the Save and Cancel buttons are not part of the Powerapp, I don't know if I'm explaining this right. I've added a screenshot to help understand.

I've tried adding a validation condition in Sharepoint, and that does prevent the user from submitting, but the error message shown is something like "There was an error with the source data ID{981273918273189237}" and that doesn't look good.

If anyone has some ideas, I'd love to hear them, thank you.

[Jeff_Thorpe · Accepted solution]

You can go to the SharePointIntegration control and in the Advance property you can add logic to the OnSave event to prevent it from being saved it the box is checked. 

[U_Idigoras]

You are absolutely right Jeff, I didn't even know that was an option.

Thank you!