Hi, Thanks for your valuable response. The properties are on the block content model at backend. The first preference is to use checkboxes only one option to be selected. If not checkboxes then as you said radio buttons

Actually normally what I do is just provide a dropdown list and therefore only one option can be selected.
However if you want to use checkboxes you can implement the IValidate interface for the block type and validate that only one has been selected which will stop the editor from being able to publish and show a red error in the validation area https://docs.developers.optimizely.com/content-cloud/v12.0.0-content-cloud/docs/validating-object-instances

Or create a validation attribute. Here is a good blog article on it https://www.wearediagram.com/blog/improving-episervers-content-editing-experience-through-validation

If I want to implement radio buttons will IValidate interface work?

IValidate just validates the IContent as it saves so anything you can expose as a property will work.

Yes I got your point, but in my case there will be 3 or 4 checkboxes in different blocks and I want to make a common validator for them

Yes sure, just radio buttons or dropdowns don't require a validator. It's just intrinsic that they only allow one so you don't need to create anything. Just suggestions

I understood but right now it's not allowing one, I can select multiple at a time which I want to restrict before editor publish it

public class A: BlockData
{

[Display(
Name = "Information.",
Description = "Information",
Order = 10)]
public virtual bool Information { get; set; }

[Display(
Name = "Warning",
Description = "Warning",
Order = 20)]
public virtual bool Warning { get; set; }

[Display(
Name = "Error",
Description = "Error",
Order = 30)]
public virtual bool Error { get; set; }
}

this is how block looks like

I was talking about a dropdown or checkbox list and they would be implemented as a single property not separate properties as you've done with your separate bools. You would just implement one property with a selection factory as shown here https://docs.developers.optimizely.com/content-cloud/v12.0.0-content-cloud/docs/single-or-multiple-list-options. Usually we load them just from an Enumeration that can be updated on any their usages as per https://errorcotidianam.wordpress.com/2020/07/29/episerver-11-creating-dropdown/. Conceptually if you're creating a selection value you usually just set it up with optimizely as a single property rather than individual properties as it's confusing to the editor.

Hi, I got your point and implemented a single property, Is there any checkbox click event available for that single property??