c# - Delegate with generic list signature for passing data to another form -

i'm quite new in c#, i'm struggling more 2 days. hope 1 can me out one.

below simplified code application.

i want pass list form1 form2 using delegate , event.

how can this? read tons of explanations events , delegates, still can't figure out, how works.

form1:

public delegate list<string> profileimporteventhandler(); public event profileimporteventhandler profileimported;  private void btnimport_click(object sender, eventargs e) {  // raise event  onprofileimported(); } protected virtual void onprofileimported() {    if (profileimported != null) // check if there subscribers    {             profileimported();    } } 

form2:

public partial class form2 : form {     form1 frm1;     public form1()     {       // constructor logic       frm1.profilechanged += new form1.profileimporteventhandler(form1_onprofileimported);     } }  list<string> form1_onprofileimported() {     // } 

update

none of solutions worked far. here have tried:

form 2

    // use generic list profiles imported usb-stick     private list<string> profilepaths = new list<string>();      public delegate void profileimporteventhandler(object sender, profileimporteventargs e);     public event profileimporteventhandler profileimported;      public delegate void importbuttonclickedeventhandler();     public event importbuttonclickedeventhandler buttonimportclicked;      public delegate void havedatadelegate(ilist<string> data);     public event havedatadelegate havedata; //....      private void btnimport_click(object sender, eventargs e)     {         // something...           // raise event         var ea = new profileimporteventargs(profilepaths);         onprofileimported(ea);          onbuttonimportclicked();          // when there data:         var copy = havedata; // use copy avoid race conditions         if (copy != null)         {             copy(profilepaths);         }         // close form       this.dispose();             }       protected virtual void onprofileimported(profileimporteventargs ea)     {         if (profileimported != null) // check if there subscribers         {             profileimported(this, ea);         }     }     protected virtual void onbuttonimportclicked()     {         if (buttonimportclicked != null)         {             // fire event             buttonimportclicked();         }     } 

form 1

public partial class frm_1 : form { // child form frm_2 frm2; public frm_1()     {         initializecomponent();         // something...          // not sure if correct code , correct place         frm2 = new frm_2();         frm2.profileimported += new frm_2.profileimporteventhandler(frm2_onprofileimported);         //frm2.profileimported += frm2_onprofileimported;          frm2.buttonimportclicked += new frm_2.importbuttonclickedeventhandler(frm2_buttonimportclicked);         // in creation/init:         frm2.havedata += datafromform2;     }    void frm2_onprofileimported(object sender, profileimporteventargs e)     {         //                  }      void frm2_buttonimportclicked()     {         //                  }      private void datafromform2(ilist<string> data)     {         // process data form2.                 }   } 

what still missing? thank help.

frm1.profilechanged += new form1.profileimporteventhandler(form1_onprofileimported); 

[…]

list<string> frmloadprofileusb_onprofileimported() 

first names not match. second, matching signatures not need (since c#2 if recall correctly) explicitly create delegate. thus:

frm1.profilechanged += frmloadprofileusb_onprofileimported; 

however, think have event in wrong place. appears form2 trying pass data form1. event needs on form2, delegate passed data. thus:

in form2

public delegate void havedatadelegate(ilist<string> data); public event havedatadelegate havedata;  // when there data: var copy = havedata; // use copy avoid race conditions if (copy != null) {   copy(data); } 

in form1

// in creation/init: form2instance.havedata += datafromform2;   private void datafromform2(ilist<string> data) {   // process data form2. }