当子窗体处于活动状态时，如何编辑父窗体？

Question

When I open a child Form, I need the parent Form to remain accessible.
For example, I could type in a text field.

Answer 1

You should use user controls for this type of functionality.

by using user controls you can use single form with multiple user controls at a time.

to know how user control works: watch this video

OR

by using show(), Hide(), BringToFront() and SendToBack() you can do but it will add complexity to your code.

Answer 2

You can open it by Show, but maybe set original form as owner, so that it does not move to background.

        var f2 = new Form2();
        f2.Owner = this;
        f2.Show();