Using a BindingSource in a UserControl

As per your question, I can hardly get what you intend to do. Thus I will try my best to provide you with, I hope, interesting information on that matter.

First, let's consider the following UserControl in a Customer management software project.

public partial class CustomerManagementUserControl : UserControl {
    public CustomerManagementUserControl() {
        InitializeComponent();
        _customerBindingSource = new BindingSource();
    }
    public IList<ICustomer> DataSource {
        set {
            _customerBindingSource.DataSource = value;
        }
    }
    private BindingSource _customerBindingSource;
}

Second, let's consider the following Form which should be your Customer management form.

public partial class CustomerManagementForm : Form {
    public CustomerManagementForm() {
        InitializeComponent();
        _customerUserControl = new CustomerManagementUserControl();
        _customerUserControl.Name = @"customerUserControl";
    }
    private void CustomerManagementForm_Load(object sender, EventArgs e) {
        // CustomersFacade is simply a static class providing customer management features and requirements.
        // Indeed, the GetCustomers() method shall return an IList<ICustomer>.
        // The IList type and typed IList<T> are both intended to be bindable as a DataSource for DataBinding.
        _customerUserControl.DataSource = CustomersFacade.GetCustomers();
        this.Controls.Add(_customerUserControl);
    }
    private CustomerManagementUserControl _customerUserControl;
}

If you're expecting to use CustomerManagementUserControl.DataSource property from within the Property window, please consider adding the following on top of your property definition.

[System.ComponentModel.DesignTimeVisible(true), System.ComponentModel.DesignerCategory("CustomerUserControl"), System.ComponentModel.Description("Sets the Customer