Why won't my textbox update when I am doing the exact same thing just with a different function?

Question

My TextBox won't update! I am using it as a Log to update what other things are doing...

Form 1 code:

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.IO;
using System.Data.OleDb;
using System.Collections.Specialized;
using System.Text;

delegate void logAdd(string message);

namespace LCR_ShepherdStaffupdater_1._0
{
    public partial class Main : Form
    {
        public Main()
        {
            InitializeComponent(); 
        }

        public void logAdd(string message)
        {
            this.Log.Items.Add(message); // Doesnt add to textbox

            this.Log.Items.Add("This won't update the textbox!!! Why?"); // Doesnt add to textbox
        }

        private void exitProgramToolStripMenuItem_Click(object sender, EventArgs e) 
        {
            Application.Exit(); 
        }
        private void aboutToolStripMenuItem1_Click(object sender, EventArgs e)
        {
            Form aboutBox = new AboutBox1(); 
            aboutBox.ShowDialog(); 
        }

        private void settingsToolStripMenuItem_Click(object sender, EventArgs e)
        {
        }

        private void settingsToolStripMenuItem1_Click(object sender, EventArgs e)
        {
            settingsForm.settings.ShowDialog();
        }

        private void synchronize_Click(object sender, EventArgs e)
        {
            this.Log.Items.Add("This WILL update the textbox. It is exactly the same as the other one..."); // This will add to the textbox
            DatabaseHandling.createDataSet();
        }

    }

    public class settingsForm 
    {
        public static Form settings = new Settings();
    }

}

My Logging Class code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace LCR_ShepherdStaffupdater_1._0
{
    public class Logging
    {
        static Main mainClass = new Main();
        static logAdd logAddDelegate;

        public static void updateLog(string message)
        {
            logAddDelegate = mainClass.logAdd;
            logAddDelegate(message);
        }
    }
}

I am just completely stumped....does anyone know how I can fix the logAdd function so I can get my textbox log to finally update?

EDIT:

I finally got it to work, here was the fix:

Form1 Code

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.IO;
using System.Data.OleDb;
using System.Collections.Specialized;
using System.Text;

delegate void logAdd(string message);

namespace LCR_ShepherdStaffupdater_1._0
{
    public partial class Main : Form
    {
        public Main()
        {
            InitializeComponent(); 
        }

        public void add(string message)
        {
            this.Log.Items.Add(message);
        }
        public void logAdd(string message)
        {
            Log.Invoke(new logAdd(add), new object[] { message });
        }

        private void exitProgramToolStripMenuItem_Click(object sender, EventArgs e) 
        {
            Application.Exit(); 
        }
        private void aboutToolStripMenuItem1_Click(object sender, EventArgs e)
        {
            Form aboutBox = new AboutBox1(); 
            aboutBox.ShowDialog(); 
        }

        private void settingsToolStripMenuItem_Click(object sender, EventArgs e)
        {
        }

        private void settingsToolStripMenuItem1_Click(object sender, EventArgs e)
        {
            settingsForm.settings.ShowDialog();
        }

        private void synchronize_Click(object sender, EventArgs e)
        {
            logAdd("this works");
        }

    }

    public class settingsForm 
    {
        public static Form settings = new Settings();
    }

}

Logging Code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace LCR_ShepherdStaffupdater_1._0
{
    public class Logging
    {
        static Main mainClass = new Main();
        static logAdd logAddDelegate;

        public static void updateLog(string message)
        {
            logAddDelegate = mainClass.logAdd;
            logAddDelegate(message);
        }
    }
}

Well...I can tell that is a really bad way to do it...but until I find a true fix as long as it works im happy. Thanks for the help guys!

Answer 1

What thread are you calling Logging.updateLog() from? If it's not the UI thread, I could see that the TextBox wouldn't get updated in that case. If you try calling logAdd() from synchronize_Click() (assuming that this is called from the UI thread based on the name), does it work then?

Answer 2

From the code you posted your static Logger class is creating a new instance of the Main form. which is different than the one your running on the UI.

Overall this isn't a very good design pattern. write a comment if you want me to elaborate and give a sample.

Answer 3

the synchronize_click is run on the instance of the main form that is running. The logadd function is run on a seperate main form that you create in the logging code. For this to work, you need to pass your existing main form into the log code so that it updates the text box you can see, not the extra text box you don't.

Answer 4

I had a problem similar once before, it was solved by calling .Invalidate() on the text box after writing to it.

You could also check your message is actually getting to the textbox with:

debug.WriteLine( this.Log.Items( this.Log.Items.Count-1));

Hope that helps you.