I have a user control with a ComboBox and a TextBox. Everything is working great except I noticed that from my user control's instance object, I can access those two controls. They shouldn't be accessible except via my own exposed properties.
You can use the x:FieldModifier attribute on your controls, thusly:
<TextBox x:Name="textBox1" x:FieldModifier="private" />
Interestingly the MSDN page for x:FieldModifier doesn't give "private" as a valid value for the attribute, but I've tested it and it works.
来源：https://stackoverflow.com/questions/300255/how-do-i-make-my-controls-inside-a-usercontrol-private