Hi all,
I am currently developing some user controls so that I can use them at several places within a project. One
control is a about editing a list of addresses for a customer. Since this needs to be done at several places within
the project I want to make it a simple user
control.
The user
control contains a repeater
control. By default
the repeater displays one address item to be edited. If more addresses need to be added,
the user can click on a button to append an additional address to be entered.
The user
control should work for creating new addresses as well as editing existing ones.
The address business entity looks something like this:
public class Address
{
public string Street { get; set; }
public City City { get; set; }
public Address(string street, City city)
{
Check.NotNullOrEmpty(street);
Check.NotNull(city);
Street = street;
City = city;
}
}
As you can see an address can only be instantiated if there is a street and a city.
Now my idea was that
the user
control exposes a collection property called Addresses.
The getter of this property collects
the addresses from
the repeater and return it in a collection.
The setter would databind
the addresses to be edited to
the repeater.
Like this:
public partial class AddressEditControl : System.Web.UI.UserControl
{
public IEnumerable<Address> Addresses
{
get
{
IList<Address> addresses = new List<Address>();
// collect items from repeater and create addresses
foreach (RepeaterItem item in addressRepeater.Items)
{
// collect values from repeater item
addresses.Add(new Address(street, city));
}
return addresses;
}
set
{
addressRepeater.DataSource = value;
addressRepeater.DataBind();
}
}
}
First I liked this approach since it is object oriented makes it very easy to reuse
the control. But at some place in my project I wanted to use this
control so a user could enter some addresses. And I wanted to pre-fill
the street input field of each repeater item since I had that data so
the user doesn't need to enter it all by his self.
Now
the problem is that this user
control only accepts addresses in a valid state (since
the address object has only one constructor). So I cannot do:
IList<Addresses> addresses = new List<Address>();
addresses.Add(new Address("someStreet", null)); // i dont know
the city yet (user has to find it out)
addressControl.Addresses = addresses;
So
the above is not possible since I would get an error from address because
the city is null.
Now my question: How would I create such a control? ;)
I was thinking about using an Address DTO instead of a real address, so it can later be mapped to an address. That way I can pass in and out an address collection which addresses don't need to be valid.
Or did I misunderstood
the way user controls work? Are there
any best practices?
