Question

            Frm Form1 = new Frm();
                //here I always get the count =0
            if (Form1 .listBox2 .SelectedItems .Count  > 0)
            {
                string item;
                foreach (int i in Form1.listBox2.SelectedIndices)
                {
                    item = Form1.listBox2.Items[i].ToString();

and when I do the same in Frm I get the real number of selected items here’s the code in Frm

    public  void btnPostText_Click(object sender, EventArgs e)
    {
        listBox2.ClearSelected();
        if (listBox1.SelectedItems.Count > 0)
        {
            foreach (int index in listBox1.SelectedIndices)
                listBox2.SetSelected(index, true);
        }

from my program I am trying to post to more than one group at facebook at the same time after the log in process the user selects the groups names that he/she wants to post to at litBox1 in listBox2 there’s the groups id(s) in the same order , so when user clicks on the btnPostText I move the selection from listBox1 to listBox2′ ,,, Now in Class2` I want to know if any Items are selected in listBox2 ,, the first code is in Class2. PostImg public static bool PostImg( , , ,)

Class2 contains the post procedures just like the Postimg it returns true if posted or false if not

here I am calling it in Frm

  if (Class2.PostImage(AppSettings.Default.AccessToken, textbox1.Text, textboxpic.Text) == true)
                MessageBox.Show("Post Done");

the code in Class2 is

    public static bool PostImage(string AccessToken, string Status, string ImagePath) 
    {
        try
        {
            Frm Frm = new Frm();

            if (Frm .listBox2 .SelectedItems .Count  > 0)
            {
                string item;
                foreach (int i in Frm.listBox2.SelectedIndices)
                {
                    item = Frm.listBox2.Items[i].ToString();
                    groupid = item;


                    FacebookClient fbpost = new FacebookClient(AccessToken);
                    var imgstream = File.OpenRead(ImagePath);
                    dynamic res = fbpost.Post("/" + groupid + "/photos", new
                   {
                       message = Status,
                       File = new FacebookMediaStream
                       {

                           ContentType = "image/jpg",
                           FileName = Path.GetFileName(ImagePath)
                       }.SetValue(imgstream)

                   });

                    result = true;

                }
            }
            return result;
        }
        catch (Exception ex)
        {
            System.Windows.Forms.MessageBox.Show(ex.Message);
            return false;
        }

Answer 1

First things first, some basics. Class2 and Frm are two distinct classes. Normally they cannot see each other unless you pass a reference between them.

Frm can see the PostImage method inside Class2 because it was marked as static. But it doesn’t go the other way. So you need to pass a reference to Frm when you call PostImage. Easiest way of doing this is including it in the method signature:

public static bool PostImage(string AccessToken, string Status, string ImagePath, Frm MyForm) 

Now you call it:

if (Class2.PostImage(AppSettings.Default.AccessToken, textbox1.Text, textboxpic.Text, this) == true)

Notice how we passed this as a parameter in the function. This is the reference we are going to use inside PostImage:

if (MyForm.listBox2.SelectedItems .Count  > 0)

And so on and so forth. The variable MyForm is now a reference to the form that called Class2.PostImage.