CODEWITHSUNDEEP
c#winforms
XandrUu
XandrUu

Reputation: 1179

Can't add items to listbox from another class C#

I'm trying to add items to listbox from another class,the information pass to the function but the listbox doesn't seem to update. this is my code:

Main class (FORM) :

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }

    // the function that updates the listbox
    public void logURI(string OutputLog, string Information, string JOB)
    {
        try
        {
            listBox1.BeginUpdate();
            listBox1.Items.Insert(0, DateTime.Now.ToString() + " : " + JOB + " " + Information);
            listBox1.Items.Add("1");
            listBox1.EndUpdate();
            textBox1.Text = JOB;
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
        }
    }
}

Second Class:

public class FtpFileSystemWatcherTS
{
     Form1 logs = new Form1();
     logs.logURI( "", "Found folder modefied today (" + FileName.TrimEnd(), ") ElectricaTS"); 
}

What am I doing wrong?

Upvotes: 1

Views: 6396

Answers (2)

Samuel Slade
Samuel Slade

Reputation: 8613

You are creating the Form from within the other class - any changes you make for the Form's children will not be displayed because it is another form that is being shown. Instead, you want to either pass the Form instance that is running into the FtpFileSystemWatcher class, so that it can access the Form.Controls property, or give it direct access to the ListBox or source of the ListBox items.

EDIT

Suggestion:

public partial class Form1 : Form
{
    private FtpFileSystemWatcher mWatcher;

    // ... some code ...

    public Form1()
    {
        InitializeComponent();

        // Create a new watcher and give it access to this form
        mWatcher = new FtpFileSystemWatcher(this);
    }

    // ... Logging code ...
}

public class FtpFileSystemWatcher
{
    private Form1 mMainForm;

    public FtpFileSystemWatcher(Form1 mainForm)
    {
        mMainForm = mainForm;
    }

    public void Log()
    {
        mMainForm.logUri(...);
    }
}

This is just an example of some code format that you could use to give the FtpFileSystemWatcher access to the running Form. This will be setup when the Form is run (assuming you have it running correctly). You should then see your desired updates.

Upvotes: 2

user1120193
user1120193

Reputation: 250

you can use inheritance easily since the procedure's access modifier is set to public

Main class (FORM) :

public partial class Form1 : Form
{

    public Form1()
    {
        InitializeComponent();

    }

   // the function that updates the listbox
   public void logURI(string OutputLog, string Information, string JOB)
    {
        try
        {
            listBox1.BeginUpdate();
            listBox1.Items.Add("0");
            listBox1.Items[0] = DateTime.Now.ToString() + " : " + JOB + " " + Information;
            listBox1.Items.Add("1");
            listBox1.EndUpdate();
            textBox1.Text = JOB;
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
        }
    }

}

public class FtpFileSystemWatcherTS : Form1
{
     logURI( "", "Found folder modefied today (" + FileName.TrimEnd().toString(), ") ElectricaTS"); 
}

Upvotes: 0

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