Can not access user control component [closed]

Answer 1

Your datagridview is private to the user control. You can confirm this by inspecting the CCCustomers.designer.cs file where the code for your datagridview is auto-generated.

The correct way to populate the datasource is to create a public method on your usercontrol eg

public void LoadData(List<Customer> customers)
{
    dgvCustomers.DataSource = customers;
}

which you would call from your main form like so:

private void Form1_Load(object sender, EventArgs e)
{
    db = new DatabaseContext();
    CCCustomers.LoadData(db.Customers.ToList());
}