C# - populating a single combobox with two columns from a database using entities

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C#

entity-framework

Hey!

so I'm trying to get the thing described in the title working. I have my database called customerDB with two tables in it, customerdata and contacts. I want to populate the combobox with the values of the columns FirstName and LastName from all rows in the table customerdata. I've tried a few different solutions, yet none of them add anything to the combobox. This is what I currently have, help would be greatly appreciated

What I have tried:

using (customerDBEntities c = new customerDBEntities())
{
    comboBox1.ValueMember = "PKCustomer"; //Primary Key of the customerdata Table
    comboBox1.DisplayMember = "FirstName" + "LastName";
    comboBox1.Invalidate();