These are 4 attribuits applied to the given property, and normally they are used in the context of validation, and here are the meaning:
1.
Required
- mark the property as required, and if the user forgot to enter a value for this property the associated message will be shown.
2.
StringLength
- set the max length of the string to 100, but the error message is not set correctly in this case. See details here:
http://msdn.microsoft.com/en-us/library/system.componentmodel.dataannotations.stringlengthattribute(v=vs.110).aspx[
^]
3.
RegularExpression
set the regular expression that will be used to validate the
user
input.
4.
Display
- set the default display name for this property. This will be used in ASP.NET MVC in the generated Views as the name of the label for this property.