Question

I’ve inserted a few StaffRole files into a combobox using the below;

for (int i=0; i < staffRoles.Count; i++)
        {
            user_Role_Combo.Items.Add(staffRoles[i]);
        }

I’m trying to search the index of a specific element within the combo box so it displays the correct element when loaded, I’ve got this, but it just returns -1 everytime;

StaffRole sr = new StaffRole("",roleID);
int comboBoxID = user_Role_Combo.Items.IndexOf(sr);

I’m doing this correct way no?!

Answer 1

In order for your new StaffRole instance to be ‘found’ in the combobox you need to describe why two StaffRole instances should be considered equivalent.

So you need to override Equals and GetHashCode. Technically, you need only Equals, but these two methods need to be overriden together.

One way to deal with it is to base object equality on roleId equality, like this:

    public override int GetHashCode() {
        return roleId.GetHashCode();
    }

    public override bool Equals(object obj) {
        if (obj == this) return true;
        var other = obj as StaffRole;
        if (other == null) return false;
        return roleId == other.roleId;
    }