# Required

> ![docs image](https://dev-assets.cms.uipath.com/assets/images/sdk/sdk-docs-image-105400-d2e86423-33e7b986.webp)

![docs image](https://dev-assets.cms.uipath.com/assets/images/sdk/sdk-docs-image-105400-d2e86423-33e7b986.webp)

Generated Code

Design-time validations are generated in `CacheMetadata` for all required properties. This means a workflow will not run unless values are provided for these fields.

```
...
  
 #region Protected Methods
protected override void CacheMetadata(CodeActivityMetadata metadata)
{
  if (FirstNumber == null) metadata.AddValidationError(string.Format(Resources.ValidationValue_Error, nameof(FirstNumber)));
  if (SecondNumber == null) metadata.AddValidationError(string.Format(Resources.ValidationValue_Error, nameof(SecondNumber)));
  base.CacheMetadata(metadata);
}
...
```

Effect in UiPath Studio

All required input properties are added to the designer automatically. If any are left empty, a validation error is shown in the top-right corner of the activity.

![docs image](https://dev-assets.cms.uipath.com/assets/images/sdk/sdk-docs-image-105320-6db73ca5-9798c9e2.webp)