Access TextBox value from One WPF form to another WPF form

Question

Hi Sir, Mam,

I would like to ask how can I access the textbox value like UserName in Login WPF into

another WPF form? I am trying to initialize the form LoginWindow objLogin = new LoginWindow ()

MessageBox.Show(objLogin.user_name_txt.Text); but it return null

Thank you.

Regards,

Rodel