c# - Accessing one from another form, is it because it is a reference? -

i have tabcontrol in form 1 named tbcontrol. when press button example, change index of tabcontrol :

this.tbcontrol.selectedindex = 2; 

it works.

then have form 2, in have done :

form1 form1 = new form1(); 

then try example :

form1.tbcontrol.selectedindex=1; 

but doesn't work, tabcontrol doesn't change index. can tell me why ?

you changing selectedindex on unshown new form1. want change selectedindex on existing form1, you'll need find way pass other form. psuedo-code:

class form1 {     private void onshowform2()     {         form2 f2 = new form2();         f2.mainform = this;         f2.show();     } }  class form2 {     public form1 mainform { get; set; }     private void dostuff()     {         //change selected index on passed in instance of form1         mainform.tbcontrol.selectedindex=1;     }  }