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Question

Am trying to dynamically add listboxes and pictures to dynamically created tabpages within a tabcontrol using c#. The form has a button which creates dynamically tabpages to the tabcontrol and also adds inside listboxes and some other content.

The problem is when I hit the button the second time it deletes everything from the previous tab and adds it to the last one.

    private void AddNewPr_Click(object sender, EventArgs e)
    {
        TabPage tab = new TabPage();
        ListBox list = new ListBox();
        ListBox list2 = new ListBox();
        PictureBox pictureBox = new PictureBox();
        PictureBox pictureBox2 = new PictureBox();
        tab.Name = "tabPage" + n;
        tab.Text = "Property " + n;
        tabControl1.Controls.Add(tab);
        list.Items.AddRange(new object[] {
                "Id",
                "Name"
        });
     //more list properties here///
     //other items here created/////

        tab.Controls.Add(list);
        tab.Controls.Add(list2);
        tab.Controls.Add(pictureBox);

        n++;
    }

I also declare an integer incrementor so that all new content have their own name identity. The other problem I have is I cant access the pictureBox click event handler which is also created dynamically.

Thanks for your help..!!

Answer 1

To access the newly created items ( list , list2 ) from a different method in the class, you'll need to create class-level variables. For example, expanding your sample above a little:

public class MyForm : Form
{
    //Class-level variables, accessible to all methods in the class
    private ListBox _list;  
    private ListBox _list2;

    private void AddNewPr_Click(object sender, EventArgs e)
    {
        TabPage tab = new TabPage();
        _list = new ListBox();
        _list2 = new ListBox();
        PictureBox picBox = new PictureBox();
        picBox.Click = picBox_Click;

        //More stuff here

        //Add the controls        
        tabControl1.Controls.Add(tab);
        tab.Controls.Add(list);
        tab.Controls.Add(list2);
        tab.Controls.Add(pictureBox);
    }

    private void picBox_Click(object sender, EventArgs e)
    {
        //_list and _list2 are in scope here because they are defined at the class-level
        _list.Items.AddRange(new object()["Id", "Name"]);
    }
}