当我的文本框在resourcedictionary中时，如何保存文本输入？

I have 2 projects in the solution explorer. One has the resource dictionary located in the folder called "Themes". The other project is set to main startup, which has the MainWindow.xaml and MainWindow.xaml.cs. I'm just wondering if I could save whatever text I will input in the textbox coded in my resource dictionary and still there the next time I open the app The code would like this: I have 2 projects in the solution explorer. One