ComboBox doesn't load users

问题

private void LoadUsersToComboBox()
{
    comboBox1.DataSource = null;
    comboBox1.DataSource = peopleRepo.FindAllPeople(); /*Returns IQueryable<People>*/
    comboBox1.DisplayMember = "Name";
    comboBox1.ValueMember = "ID";            
}

private void button2_Click(object sender, EventArgs e)
{            
    CreateNewPerson();            
    LoadUsersToComboBox();
}

private void CreateNewPerson()
{
    if (textBox2.Text != String.Empty)
    {
        Person user = new Person()
        {
            Name = textBox2.Text
        };

        peopleRepo.Add(user);
        peopleRepo.Save();
    }            
}

I'd like the combobox to display a list of users, after every save. So, someone creates a new user and it should display in the combobox right after that. This isn't working, no new users are added, only the initial 'load' seems to work.

回答1:

Complex DataBinding accepts as a data source either an IList or an IListSource.

private void LoadUsersToComboBox()
{
    // comboBox1.DataSource = null; // No need for this

    comboBox1.DataSource = peopleRepo.FindAllPeople().ToList(); /*Returns IQueryable<People>*/
}

Don't reassign the DisplayMember & The ValueMember every refresh, just once,

public Form1()
{
    InitializeComponent();

    comboBox1.DisplayMember = "Name";
    comboBox1.ValueMember = "ID";
    LoadUsersToComboBox()
}

Good luck!

来源：https://stackoverflow.com/questions/4051939/combobox-doesnt-load-users