Question

I was wondering if someone could help me with a little issue I’m having. I’m trying to update a textbox from another class but the text is not showing up on in the textbox even though it is being sent as I have printed it to the screen.

The code I’m using is below:

Program.cs

namespace Search
{
    static class Program
    {
        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]

        static void Main()
        {
            Application.EnableVisualStyles();

            try
            {
                Application.SetCompatibleTextRenderingDefault(false);
            }
            catch (InvalidOperationException e)
            {

            }
            Application.Run(new Form1());
        }

        public static readonly Form1 MainLogWindow = new Form1();
    }
}

HexToASCII:

public class HexToASCII
{
    Output o = new Output();

    public void hexToAscii(String hex, int textBox)
    {
        //Convert the string of HEX to ASCII
        StringBuilder sb = new StringBuilder();

        for (int i = 0; i < hex.Length; i += 2)
        {
            string hs = hex.Substring(i, 2);
            sb.Append(Convert.ToChar(Convert.ToUInt32(hs, 16)));
        }
        //Pass the string to be output
        string convertedHex = sb.ToString();

        Program.MainLogWindow.UpdateTextBox(convertedHex);    
    }
}

Form1:

    private delegate void NameCallBack(string varText);
    public void UpdateTextBox(string input)
    {  
        if (InvokeRequired)
        {
            textBox2.BeginInvoke(new NameCallBack(UpdateTextBox), new object[] { input });
        }
        else
        {
            textBox2.Text = textBox2.Text + Environment.NewLine + input; 
        }
    }

I have tried to run it using a new thread ThreadStart ts = delegate()… but I’m unable to get the textbox to update. Sorry I’m very new to c#, could someone please explain the issue so I can understand it and learn for next time. Many thanks 🙂

Answer 1

This is the problem:

static void Main()
{
    ...
    Application.Run(new Form1());
}

public static readonly Form1 MainLogWindow = new Form1();

You’re creating two forms: one of them is being shown (with Application.Run) but you’re changing the contents of the text box on the other one:

Program.MainLogWindow.UpdateTextBox(convertedHex);  

You haven’t shown how you’re calling hexToAscii in the first place – personally I would try to avoid having static references to GUI elements like this, but you could get your code to work just by changing your Main method to use:

Application.Run(MainLogWindow);