How to change the display format of a field using MetaData

Let’s assume you have a Domain Service class that you are access from your ASP.NET Dynamic Data application (should work for Silverlight client as well (I think)) and that you have a table called Person. The Person table has a field / property / column that is called BirthDate. By default it is displayed as a date AND time in the GridView and the Edit and Detail Forms. The way to change the display format is in the MetaData for the Person table. In particular the MetaData for the property BirthDate. The basic MetaData class is generated for you when you create the Domain Service class.

The question is what Attribute do we use to communicate what we want. The answer is: DataFormatAttribute. Use it like you would a string format in most other places in the .NET framework. In the example below only the date (not the time) will always be shown.

[DisplayFormat(DataFormatString = "{0:d}", ApplyFormatInEditMode=true)]
public DateTime PerformedOnDateTimeUtc { get; set; }

If we remove or set the ApplyFormatInEditMode parameter to false (as shown below) then insert and edit will still show the time, but the gridview will still only show the date (no time).

[DisplayFormat(DataFormatString = "{0:d}", ApplyFormatInEditMode=false)]
public DateTime PerformedOnDateTimeUtc { get; set; }

You can use custom date formats, use on different datatypes, etc.