How can I auto detect current form's id in Sitecore

Question

I want to create a custom email validator to check if email exists or no to do that I must know the form's id so that to get its data I can do that using this code

ID ID = new ID("{form id}");
var data = this.FormDataProvider.GetEntries(ID.Guid, null, null);

so its hard coded which I don't want as it will work for only one form and I want it to be general How can I auto detect the ID of the form through code?