Populating listview control passing parameters to constructor from another form

Question

I need to populate a listview control on Takenshows.cs form, passing parameters to constructor from Main.cs form.

When I'm running the code, the listview is empty. I don't know what is wrong with my code.

Here's the main.cs form on button when I'm sending parameters to Takenshows.cs form:

shows = new Takenshows(Ordnumber,meddt, values, 
   num);

And this is the Takenshows.cs form:

      int Ordnum;
      string medDateTime;
      string val;
      int number;
          public Takenshows()
             {
                InitializeComponent();
               }

          public Takenshows(int Ordnumber, string 
                  dtmed, string values, int num)
               {
        
                  Ordnum = Ordnumber;
                  medDateTime = dtmed;
                  val = values;
                  number = num;
                  InitializeComponent();
               }

I know the problem is on Takenshows_load, but I don't know why listview doesn't fill.

     private void Takenshows_Load(object sender, EventArgs e)
        {


             for(int i=0; i< listView1.Items.Count; i++){
                         
                         listView1.Items[i].SubItems[0].Text = Ordnum.ToString();
                         listView1.Items[i].SubItems[1].Text = medDateTime;
                         listView1.Items[i].SubItems[2].Text = val;
                         listView1.Items[i].SubItems[3].Text = number.ToString();

                         ListViewItem item = new ListViewItem(listView1.Items[i].SubItems[0].Text); 
                         item.SubItems.Add(listView1.Items[i].SubItems[1].Text);
                         item.SubItems.Add(listView1.Items[i].SubItems[2].Text);        
                         item.SubItems.Add(listView1.Items[i].SubItems[3].Text);
                         listView1.Items.Add(item);
                     } 



                             }

        private void listView1_SelectedIndexChanged(object sender, EventArgs e)
         {

                }

Anything can I do to fix this issue?

By certain this is Main.cs form:

 public partial class Main : Form
{
           int Ordnumber;
           string meddt;
           string values;
           int num;
           TakenShows shows;

     public Main()
           {
        InitializeComponent();
             }

      private void button2_Click(object sender, EventArgs e)
            {
        Ordnumber = GetOrdNumberLN.getInstance().GettingOrdNumber();
        Ordnumber = Ordnumber + 1;
        meddt = DateTime.Now.ToString();
        num = GetNumberLN.getInstance().GettingNumber();
        values = textBox_F.Text + " " + textBox_PT.Text + " " + textBox_QT.Text 
        shows = new Takenshows(Ordnumber,meddt, values, 
   num);
        shows.Show();


          }
  

Answer 1

You need to keep the data you create in some collection container such as DataTable or List<T> to be able to set/get/manipulate the collected items. Here's a List<T> implementation example.

• Switch to the Solution Explorer window and select your project.
• Press Shift+Alt+C to open the Add New Item dialog.
• Rename the class to ShowItem.cs and hit the Add button.

Edit the class as follows:

public class ShowItem
{
    public ShowItem() { }

    // Find better names...
    public int Number { get; set; }
    public int OrderNumber { get; set; }
    public DateTime MedDate { get; set; }
    public string F { get; set; }
    public string PT { get; set; }
    public string QT { get; set; }
    public string Values => $"{F} {PT} {QT}";
}

Now you have the ShowItem type to create instances from it and keep them in a List<ShowItem>.

In case you want to show modal dialog, edit the Main Form as follows:

// +
using System.Collections.Generic;
// ...

public partial class Main : Form
{
    private readonly List<ShowItem> showItems;

    public Main()
    {
        InitializeComponent();
        showItems = new List<ShowItem>();
    }

    // Find a better name...
    private void button2_Click(object sender, EventArgs e)
    {
        var show = new ShowItem
        {
            OrderNumber = GetOrdNumberLN.getInstance().GettingOrdNumber() + 1,
            MedDate = DateTime.Now,
            Number = GetNumberLN.getInstance().GettingNumber(),
            F = textBox_F.Text,
            PT = textBox_PT.Text,
            QT = textBox_QT.Text
        };

        showItems.Add(show);

        using (var frm = new Takenshows(showItems))
        {
            frm.ShowDialog();
        }
    }
}

... and the Takenshows Form:

// +
using System.Linq;
// ...

public partial class Takenshows : Form
{
    public Takenshows()
    {
        InitializeComponent();
    }

    public Takenshows(IEnumerable<ShowItem> items) : this()
    {
        AddItems(items);
    }

    internal void AddItem(ShowItem item) => AddItems(new[] { item });

    internal void AddItems(IEnumerable<ShowItem> items)
    {
        var lvis = items.Select(x => new ListViewItem(new[]
        {
            x.OrderNumber.ToString(),
            x.MedDate.ToString(),
            x.Values,
            x.Number.ToString()
        }));
        listView1.Items.AddRange(lvis.ToArray());
    }
}

In contrast, if you need to keep the Takenshows Form open, then edit the button2_Click event handler in Main as shown below. Note, the access modifier of the AddItem and AddItems methods is internal for this scenario.

private void button2_Click(object sender, EventArgs e)
{
    var show = new ShowItem
    {
        OrderNumber = GetOrdNumberLN.getInstance().GettingOrdNumber() + 1,
        MedDate = DateTime.Now,
        Number = GetNumberLN.getInstance().GettingNumber(),
        F = textBox_F.Text,
        PT = textBox_PT.Text,
        QT = textBox_QT.Text
    };

    showItems.Add(show);

    var frm = Application.OpenForms.OfType<Takenshows>().FirstOrDefault();

    if (frm == null)
    {
        frm = new Takenshows(showItems);
        frm.Show();
    }
    else
    {
        frm.AddItem(show);
        frm.Activate();
    }            
}

Hope this helps you to take-off.