My Custom Control won't work when use inside of a Method in C# -

so i've made custom control in c# (it's circular progress bar), , have created variables in such min, max , value (every progress bar must have that) , whenever use variables inside of method (lets button click event) code compiles without syntax errors doesn't anything. when use inside of form's main method works fine. here's code i've described.

 public partial class form1 : form {     public form1()     {         initializecomponent();     }      private void button1_click(object sender, eventargs e)     {         circlebar1.value++;      } } 

image of i'm trying say

why declaring _value in different way how declare other 2 properties(min/max value)?

it should be:

private int _value;  public int value {     get{ return _value;}     set{ _value = value;} } 

then use like:

circle_progressbar.circlebar.value = 50;