How to access textbox/labels/combobox from another class.

Question

I have two classes  test.cs and designTest.cs
In designTest.cs ,I have label1,textbox1,combobox1 etc.
In the test.cs,I want to write the code as
designTest dt=new designTest();
//label1.visible=true;
//textbox1.visible=true;
but the problem is that label1,textbox1 or combobox1 is not accessible.
How to make them accessible in test.cs?