Reputation: 145
I'm developing a .NET application, and I have a problem. I try to populate a listbox from a MySQL database with Entity Framework. Here is my code:
public MainForm()
{
InitializeComponent();
try
{
hospitaldbEntities context = new hospitaldbEntities();
PatientlistBoxId.DataSource = context.patients;
PatientlistBoxId.DisplayMember = "FirstName";
}
catch (Exception ex)
{
Console.WriteLine(ex);
}
}
I attach a picture from the Solution Explorer:
And finally here is my patient class:
public partial class patient
{
public patient()
{
this.examinations = new HashSet<examination>();
this.diseases = new HashSet<disease>();
this.drugsensitivities = new HashSet<drugsensitivity>();
}
public int PatientID { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public System.DateTime DateOfBirth { get; set; }
public string Gender { get; set; }
public string Address { get; set; }
public System.DateTime DateOfCreate { get; set; }
public string Category { get; set; }
public int CNP { get; set; }
public virtual ICollection<examination> examinations { get; set; }
public virtual ICollection<disease> diseases { get; set; }
public virtual ICollection<drugsensitivity> drugsensitivities { get; set; }
}
Thank you for the help in advance.
EDIT
When I try to run the application, it throws an error:
Upvotes: 2
Views: 3628
Reputation: 7800
You must at least use:
PatientlistBoxId.DataSource = context.patients.ToList();
Consider using a BindingList<T>
BTW:
Consider not using an Entity type as ItemType for the ListBox.
Consider using a using
context to dispose your context, that is handle more clearly the scope of your context.
========== ==========
A little bit more details
//this class allows to separate the winform (equivalent to a view) from
//the data layer, you can see it as a ViewModel
public class FormNamePatient {
public Int32 Id { get; set;}
public String FirstName { get; set;}
public String LastName { get; set;}
}
private BindingList<FormNamePatient> _patients;
try {
//the using guarantees the disposing of the resources
//(avoiding memory link and so on)
using ( hospitaldbEntities context = new hospitaldbEntities() ) {
_patients = new BindindList<FormNamePatient>(
context.patients.Select(
x => new FormNamePatient {
Id = x.Id,
FirstName = x.FirstName,
LastName = x.LastName,
}).ToList() // this materialize the list
// in other (bad ?) words, this allows the list
//to live out of the context (<=> using)
);
}
PatientlistBoxId.DataSource ) = _patients;
//now if you alter (not erase, but edit, change...) _patients you
//update the control
PatientlistBoxId.DisplayMember = "FirstName";
} catch (Exception ex) {
Console.WriteLine(ex);
}
Upvotes: 1