Thank you for contacting Syncfusion support.
We have checked your reported requirement in our end and we would like to let you know that, currently we don’t have support for HTML Attributes in Blazor. However, we have considered this as an improvement. And the fix will be available with our Essential Studio 2019 Volume 2 Beta release, which has been scheduled to be rolled out in the last week of June, 2019. We appreciate your patience until then.