How to Update a Listbox on Another Form?

Question

Hello. I have a Listbox, listBoxA (say), on FormA. Now, there are two other Forms, FormB and FormC, with textboxes textBoxB and textBoxC. The items in listBoxA are added to via textBoxB and textBoxC; either textbox can add an item. Can this be done? How can this be done? Here's what I could come up with: Write item from either textbox to a textfile and read the items from the textfile for the listbox. It works but if FormA (with the listbox) is open, I must close it and re-open to see new item(s). Anyone know of a better way, especially where I don't have to re-open the Form with the listbox? This is in C#. Thanks!

Anwar Buchoo · Answer

All the pleasure is mine :) Rgds.

AB · Answer

Thanks Anwar, for your help!

Anwar Buchoo · Answer

Declare a static variable (FormA SingletonFormA;) of the FormA (within FormA) which is accessible to both FormB && FormC. Create a method e.g. CreateInstance(); within class FormA which has got something like: public static FormA CreateInstance() { if(SingletonFormA == null) // null check { SingletonFormA = new FormA(); // initialise it } return SingletonFormA; } Now create an object of FormA in each of classs FormB && FormC (ObjB, ObjC) and make a function call like: // class FormB ObjB = FormA.CreateInstance(); // class FormC ObjC = FormA.CreateInstance(); Then, you can call something like: ObjB.ListItem1.Add("testSingletonFromFormB", new ListItem("","")); ObjC.ListItem1.Add("testSingletonFromFormC", new ListItem("","")); The idea here is to use a shared variable amongst your forms.