C# Open form using generics?

Question

I have a main form with a menu that contains lots of items which in turn open different forms. Currently I do the following to open a particular form:

        if (canShowCustomerForm)
            new CustomerForm().ShowDialog(this);
        else
        {
            MessageBox.Show("You don't have enough rights to view this form.");
        }

Is there a way to move this code in a class and then passing the form type and boolean parameter instead of repeating the code for each and every menu item?

Answer 1

public static class FormHelper
{
    public static DisplayResult ShowForm<T>(IWin32Window owner, bool canShowForm)
        where T : Form, new()
    {
        if (canShowForm)
        {
            using (T form = new T())
            {
                return form.ShowDialog(owner);
            }
        }
        else
        {
            MessageBox.Show("You don't have enough rights to view this form.");
        }
    }
}

Answer 2

Rather than writing the same logic over and over again you can extract it into a function like below:

void ShowFormIfAllowed<TForm>(bool allowed) where TForm : Form, new() {
      if (allowed) {
          using (var form = new TForm()) {
               form.ShowDialog(this);
          }
      }
      else {
            MessageBox.Show("You don't have enough rights to view this form.");
      }
 }

Then in your menu handling you can call it like:

ShowFormIfAllowed<CustomerForm>(canShowCustomerForm);