how to navigate to other form and closing the previous one

I want to open a form (say Welcome form) by clicking on one form (say Login form ) upon clicking on submit button by closing the login form and opening the welcome form .
Steps for such scenarios in Winforms, based on good accepted design:
1. Have a main form - form A. Always keep it active.
2. Since you need login, create a child form - form B. Show it above form A.
3. If user provides correct credentials, hide/close form B and show form A with UI as per need
4. If user provides wrong credentials, show error

This way, you don't have issue with opening/closing issue with login form. Further, as you must be knowing in Winforms, parent window cannot be closed keeping child window open - thus the above said design would keep everything in check without issues.


If you still persist on following your design, have a look at these article/tip:
User Login For WinForm Applications[^]
Multiple Subsequent "Main" Forms in C# Apps[^]