updating textbox with thread?

[rookie7799]

I have loop that goes through a txt file that has about 1000000 lines of text.
I have a var. x that changes every time the program reads a line of text
Is it possible to update textbox with that x and actually see the update.
I really don't want to use DoEvents but I think it is possible with threads
Thanks

[jmcilhinney]

How much time is passing between changes in this value? If it's very short then is it really practical to show the changes to the user anyway? If you set the Text of the TextBox and call its Refresh method each time then the TextBox will be redrawn.

[jmcilhinney]

Note that if you read the file in the main thread then your UI will be unusable for the time it is running. You can read the file in a different thread, certainly. You haven't specified which version you're using (use the radio buttons on the "new thread" page) so I can't tell you whether to use a BackgroundWorker or not.

[rookie7799]

that's the unfinished code for the form
4 textboxes
3 buttons

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.IO;
using System.Threading;
 
namespace project
{
    /// <summary>
    /// Summary description for Form1.
    /// </summary>
    public class Form1 : System.Windows.Forms.Form
    {
        private System.Windows.Forms.OpenFileDialog openFileDialog1;
        private System.Windows.Forms.Button button1;
        private System.Windows.Forms.Button button2;
        private System.Windows.Forms.TextBox textBox1;
        private System.Windows.Forms.TextBox textBox2;
        private System.Windows.Forms.TextBox textBox3;
        private System.Windows.Forms.TextBox textBox4;
        /// <summary>
        /// Required designer variable.
        /// </summary>
        private System.ComponentModel.Container components = null;
        private System.Windows.Forms.Button button3;
 
        public Class1 myClass = new Class1();
        public  int x=0;
        private Thread trd;
 
        public Form1()
        {
            //
            // Required for Windows Form Designer support
            //
            InitializeComponent();          
 
            //
            // TODO: Add any constructor code after InitializeComponent call
            //
 
        }
 
        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        protected override void Dispose( bool disposing )
        {
            if( disposing )
            {
                if (components != null) 
                {
                    components.Dispose();
                }
            }
            base.Dispose( disposing );
        }
 
        #region Windows Form Designer generated code
        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {
            this.openFileDialog1 = new System.Windows.Forms.OpenFileDialog();
            this.button1 = new System.Windows.Forms.Button();
            this.button2 = new System.Windows.Forms.Button();
            this.textBox1 = new System.Windows.Forms.TextBox();
            this.textBox2 = new System.Windows.Forms.TextBox();
            this.textBox3 = new System.Windows.Forms.TextBox();
            this.textBox4 = new System.Windows.Forms.TextBox();
            this.button3 = new System.Windows.Forms.Button();
            this.SuspendLayout();
            // 
            // button1
            // 
            this.button1.Location = new System.Drawing.Point(312, 8);
            this.button1.Name = "button1";
            this.button1.Size = new System.Drawing.Size(88, 20);
            this.button1.TabIndex = 0;
            this.button1.Text = "select";
            this.button1.Click += new System.EventHandler(this.button1_Click);
            // 
            // button2
            // 
            this.button2.Location = new System.Drawing.Point(312, 32);
            this.button2.Name = "button2";
            this.button2.Size = new System.Drawing.Size(88, 20);
            this.button2.TabIndex = 1;
            this.button2.Text = "select";
            this.button2.Click += new System.EventHandler(this.button2_Click);
            // 
            // textBox1
            // 
            this.textBox1.Location = new System.Drawing.Point(8, 8);
            this.textBox1.Name = "textBox1";
            this.textBox1.Size = new System.Drawing.Size(285, 20);
            this.textBox1.TabIndex = 2;
            this.textBox1.Text = "";
            // 
            // textBox2
            // 
            this.textBox2.Location = new System.Drawing.Point(8, 32);
            this.textBox2.Name = "textBox2";
            this.textBox2.Size = new System.Drawing.Size(285, 20);
            this.textBox2.TabIndex = 3;
            this.textBox2.Text = "";
            // 
            // textBox3
            // 
            this.textBox3.Location = new System.Drawing.Point(416, 8);
            this.textBox3.Name = "textBox3";
            this.textBox3.Size = new System.Drawing.Size(80, 20);
            this.textBox3.TabIndex = 4;
            this.textBox3.Text = "";
            this.textBox3.TextChanged += new System.EventHandler(this.textBox3_TextChanged);
            // 
            // textBox4
            // 
            this.textBox4.Location = new System.Drawing.Point(416, 32);
            this.textBox4.Name = "textBox4";
            this.textBox4.Size = new System.Drawing.Size(80, 20);
            this.textBox4.TabIndex = 5;
            this.textBox4.Text = "";
            // 
            // button3
            // 
            this.button3.Location = new System.Drawing.Point(512, 32);
            this.button3.Name = "button3";
            this.button3.Size = new System.Drawing.Size(80, 20);
            this.button3.TabIndex = 6;
            this.button3.Text = "start";
            this.button3.Click += new System.EventHandler(this.button3_Click);
            // 
            // Form1
            // 
            this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
            this.ClientSize = new System.Drawing.Size(696, 86);
            this.Controls.Add(this.button3);
            this.Controls.Add(this.textBox4);
            this.Controls.Add(this.textBox3);
            this.Controls.Add(this.textBox2);
            this.Controls.Add(this.textBox1);
            this.Controls.Add(this.button2);
            this.Controls.Add(this.button1);
            this.Name = "Form1";
            this.Text = "Form1";
            this.Load += new System.EventHandler(this.Form1_Load);
            this.ResumeLayout(false);
 
        }
        #endregion
 
        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main() 
        {
            Application.Run(new Form1());
            
        }
 
        private void button1_Click(object sender, System.EventArgs e)
        {
            openFileDialog1.ShowDialog();
            myClass.setPath1(openFileDialog1.FileName);
            textBox1.Text = myClass.getPath1();
        }
 
        private void button2_Click(object sender, System.EventArgs e)
        {
            openFileDialog1.ShowDialog();
            myClass.setPath2(openFileDialog1.FileName);
            textBox2.Text = myClass.getPath2();
        }
 
        private void Form1_Load(object sender, System.EventArgs e)
        {
            Thread trd = new Thread(new ThreadStart(this.ThreadTask));
            trd.IsBackground = true;
            trd.Start();
        }
 
        private void textBox3_TextChanged(object sender, System.EventArgs e)
        {
        
        }
 
        private void button3_Click(object sender, System.EventArgs e)
        {
            String [] myArr;
            String line;
            ArrayList myList = new ArrayList();
 
            using (StreamReader sr = new StreamReader(textBox1.Text)) 
            {
            
                while ((line = sr.ReadLine()) != null) 
                {
                    myList.Add(sr.ReadLine());
                    x ++;                   
                }
            //trd.Abort();
            }
        }
        private void ThreadTask()
        {
            while (true )
            {
                textBox3.Text = x.ToString();
                Thread.Sleep(100);
                textBox3.Refresh();
            }
        }
    }
}

Thats the simple class i have

using System;
 
namespace project
{
    /// <summary>
    /// Summary description for Class1.
    /// </summary>
    public class Class1
    {
        private string file1Path="";
        private string file2Path ="";
 
        public Class1()
        {       
            //
            // TODO: Add constructor logic here
            //
        }
        public void setPath1(string x)
        {
            file1Path = x;
        }
        public void setPath2(string x)
        {
            file2Path = x;
        }
        public string getPath1()
        {
            return file1Path;
        }
        public string getPath2()
        {
            return file2Path;
        }
    }
}

I'm using MS Visual Studio .NET 2003

Thanks

[jmcilhinney]

I'm not quite sure what you're expecting.

[rookie7799]

I'm not quite sure what you're expecting.

You know like in VB if we have a loop from 0 to 99999999 and when we run it without doevents and would want to see the progress in a textbox, it will only show the last 99999999 number, however if we insert DoEvents inside the loop we can actually see how it counts, that's what I want in C#

[jmcilhinney]

The insert DoEvents. DoEvents is a method of the Application class and is available in C# just like it is in VB.NET.

[rookie7799]

The insert DoEvents. DoEvents is a method of the Application class and is available in C# just like it is in VB.NET.

I've read in many places that Doevents is not really a good method of doing this kind of thing, that's why i'm looking for alternative.

Thanks

[jmcilhinney]

That's quite correct. DoEvents will check for any pending events at all and it will block until they are all handled. The checking is relatively expensive. If all you want is to update a specific control then you should call Refresh on that control, which is what I advised earlier. I don't see the issue. For example:

            for (int i = 0; i < 100; i++)
            {
                this.label1.Text = i.ToString();
                this.label1.Refresh();
                System.Threading.Thread.Sleep(100);
            }