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?
