Fill ModelMetadata gaps needed for HTML helpers

[dougbu]

The HTML helpers aren't completely copied over but already contain TODO items for missing ModelMetadata properties:

• DisplayName, which is particularly important
• HideSurroundingHtml, the opposite of [Hidden] attribute’s DisplayValue property
• SimpleDisplayText (and protected virtual GetSimpleDisplayText() method), which @sornaks has already begun adding
• ShowForDisplay, which we might need to skip since [ScaffoldColumnAttribute] doesn't seem to exist (yet?)

In addition the default editor templates need:

• HasNonDefaultEditFormat
• ShowForEdit, with same caveat as ShowForDisplay

And finishing validation will require:

• IsRequired !!

[JaneZhouQ]

MusicStore requires DisplayName and ScaffoldColumn.

[sornaks]

DisplayName is already present - 7273286

[JaneZhouQ]

@sornaks, could you please update #532 and assign that issue to @kirthik to validate?

[sornaks]

@JaneZhouQ - Just discussed with @dougbu . As he has mentioned in the other issue, there is a TODO for this item to be complete.

[dougbu]

Closing this one because we now have issues for all remaining pieces. Current status:

• SimpleDisplayText, ShowForDisplay, ShowForEdit, and IsRequired done
  • small fix for IsRequired included in [DisplayName] PR
• [DisplayName] support out for PR Add DisplayName property to ModelMetadata #841 (issue Support DisplayName Attribute #532)
• leaves only HideSurroundingHtml (issue Add HideSurroundingHtml property to ModelMetadata #843) and HasNonDefaultEditFormat (issue Support [DisplayFormat(DataFormatString="{format})] #844)