Why is the CheckedListBox DisplayMember not displaying?

Question

I'm trying to do something very simple - bind a CheckedListBox to a list of objects.

Class definition

namespace Models
{
    public class Department
    {
        public int ID { get; set; }
        public string Description { get; set; }
    }
}

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Minimal complete code sample to replicate the issue

(Create CheckedListBox clbDepartments first)

    private void Form1_Load(object sender, EventArgs e)
    {
        List<Department> departmentList = new List<Department>();
        departmentList.Add(new Department { ID = 1, Description = "HR" });
        departmentList.Add(new Department { ID = 2, Description = "IT" });
        departmentList.Add(new Department { ID = 3, Description = "Sales" });

        var departmentBindingList = new BindingList<Department>(departmentList);
        var departmentSource = new BindingSource(departmentBindingList, null);
        clbDepartments.DisplayMember = "Description";
        clbDepartments.ValueMember = "ID";
        clbDepartments.DataSource = departmentSource;
    }

The list binds - I can see one item in the CheckboxList per item in the List<Department>.

But instead of displaying the value of the "Description" field, which is the DisplayMember, the list displays "Models.Department" for each item.

Expected Output

HR

IT

Sales

---

Actual Output

Models.Department

Models.Department

Models.Department

What am I doing wrong?

Answer 1

You should change the order.
First set the DataSource and then set the DisplayMember and ValueMember

This should work:

clbDepartments.DataSource = departmentSource;
clbDepartments.DisplayMember = "Description";
clbDepartments.ValueMember = "ID";