WebBrowserComplete only firing once.

Question

This is my event:

private void webBrowser1_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
        {
           //stuff
           //screenscraping,datatable creation
       }

This is a button on my form:

        private void button2_Click(object sender, EventArgs e)
        {
            //Navigate to the URL in the row dictated by the counter value, get val of 3rd column over
            webBrowser1.Navigate(dataGridView1[2,citycounter].Value.ToString());
            citycounter++;
         }

------------------------------------------

When I click the button, my webbrowser object navigates to the correct page, and the documentcomplete event fires, causing "stuff" to happen. When I click the button again, webbrowser object navigates to the correct page, but does not fire the documentcomplete event. Everytime I click, the browser reacts correctly and navigates to the next page in my datagrid, but the documentcomplete event does not fire after the first time.

Any ideas?

Answer 1

Hey Derek,

Can you try isolating the problem?

Start a new project, drop on a button (dock it top) and web browser. Add a couple event handlers:

private void button1_Click(object sender, EventArgs e)

{

    webBrowser1.Navigate("yahoo.ca");

}

private void webBrowser1_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)

{

    Debug.WriteLine(string.Format("woot {0}", DateTime.Now.ToLongTimeString()));

}

I noticed in running this that Document completed comes back once, real quick, then a couple times a second or two later.

If nothing else comes into play, I might suspect that you have some long-running thing happening in the browser (or on the server)?  

Can you debug the server to see what's going on?  If you run a debug session locally, can you just step through and see if there's something happening otherwise?

Cheers,

-jc

---

Me, coding and stuff: Mr. James

Answer 2

Well, the page I'm hitting is http://www.mta.info/nyct/index.html.

I'm scraping the news section for links, and then visiting each link sequentially.

The first link opens correctly, and executes //stuff (populates a datagrid, and ticks a counter.)
second link opens correctly, but does not execute //stuff

This is regardless of the page I point the browser at.

If I force page visit counter to start from URL 1 instead of 0, then URL 1 will work properly
and URL 2 will fail to trigger DocumentComplete.

If I visit URL 1, then URL 0, then URL 1 will work, and URL 0 will fail to trigger DocumentComplete.

I'm new to this whole coding game, but I think I've ruled out it being a server side issue right?

Answer 3

You just might be seeing cached pages. 
Try out this browser demo. 
I get similar results when I re-visit the page over and over.


    class ProgressBrowser : Form
    {
        #region form.designer.cs file
        /// <summary>
        /// Required designer variable.
        /// </summary>
        private System.ComponentModel.IContainer components = null;

        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing && (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.btn_Go = new System.Windows.Forms.Button();
            this.btn_Refresh = new System.Windows.Forms.Button();
            this.webBrowser1 = new System.Windows.Forms.WebBrowser();
            this.progressBar1 = new System.Windows.Forms.ProgressBar();
            this.txt_StatusBox = new System.Windows.Forms.TextBox();
            this.lbl_StatusTxt = new System.Windows.Forms.Label();
            this.cbo_AddressBar = new System.Windows.Forms.ComboBox();
            this.label2 = new System.Windows.Forms.Label();
            this.label1 = new System.Windows.Forms.Label();
            this.SuspendLayout();
            //
            // btn_Go
            //
            this.btn_Go.Location = new System.Drawing.Point(466, 11);
            this.btn_Go.Name = "btn_Go";
            this.btn_Go.Size = new System.Drawing.Size(75, 23);
            this.btn_Go.TabIndex = 1;
            this.btn_Go.Text = "GO";
            this.btn_Go.UseVisualStyleBackColor = true;
            this.btn_Go.Click += new System.EventHandler(this.btn_Go_Click);
            //
            // btn_Refresh
            //
            this.btn_Refresh.Location = new System.Drawing.Point(548, 10);
            this.btn_Refresh.Name = "btn_Refresh";
            this.btn_Refresh.Size = new System.Drawing.Size(75, 23);
            this.btn_Refresh.TabIndex = 2;
            this.btn_Refresh.Text = "Refresh";
            this.btn_Refresh.UseVisualStyleBackColor = true;
            this.btn_Refresh.Click += new System.EventHandler(this.btn_Refresh_Click);
            //
            // webBrowser1
            //
            this.webBrowser1.Location = new System.Drawing.Point(12, 40);
            this.webBrowser1.MinimumSize = new System.Drawing.Size(20, 20);
            this.webBrowser1.Name = "webBrowser1";
            this.webBrowser1.Size = new System.Drawing.Size(611, 476);
            this.webBrowser1.TabIndex = 3;
            //
            // progressBar1
            //
            this.progressBar1.Location = new System.Drawing.Point(119, 523);
            this.progressBar1.Name = "progressBar1";
            this.progressBar1.Size = new System.Drawing.Size(371, 23);
            this.progressBar1.TabIndex = 4;
            //
            // txt_StatusBox
            //
            this.txt_StatusBox.Location = new System.Drawing.Point(13, 523);
            this.txt_StatusBox.Name = "txt_StatusBox";
            this.txt_StatusBox.Size = new System.Drawing.Size(100, 20);
            this.txt_StatusBox.TabIndex = 5;
            //
            // lbl_StatusTxt
            //
            this.lbl_StatusTxt.AutoSize = true;
            this.lbl_StatusTxt.Location = new System.Drawing.Point(13, 550);
            this.lbl_StatusTxt.Name = "lbl_StatusTxt";
            this.lbl_StatusTxt.Size = new System.Drawing.Size(68, 13);
            this.lbl_StatusTxt.TabIndex = 6;
            this.lbl_StatusTxt.Text = "lbl_StatusTxt";
            //
            // cbo_AddressBar
            //
            this.cbo_AddressBar.FormattingEnabled = true;
            this.cbo_AddressBar.Location = new System.Drawing.Point(12, 13);
            this.cbo_AddressBar.Name = "cbo_AddressBar";
            this.cbo_AddressBar.Size = new System.Drawing.Size(448, 21);
            this.cbo_AddressBar.TabIndex = 7;
            //
            // label2
            //
            this.label2.AutoSize = true;
            this.label2.Location = new System.Drawing.Point(497, 532);
            this.label2.Name = "label2";
            this.label2.Size = new System.Drawing.Size(35, 13);
            this.label2.TabIndex = 8;
            this.label2.Text = "totalProgress";
            //
            // label1
            //
            this.label1.AutoSize = true;
            this.label1.Location = new System.Drawing.Point(497, 554);
            this.label1.Name = "label1";
            this.label1.Size = new System.Drawing.Size(35, 13);
            this.label1.TabIndex = 9;
            this.label1.Text = "currentProgress";
            //
            // Form1
            //
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(633, 576);
            this.Controls.Add(this.label1);
            this.Controls.Add(this.label2);
            this.Controls.Add(this.cbo_AddressBar);
            this.Controls.Add(this.lbl_StatusTxt);
            this.Controls.Add(this.txt_StatusBox);
            this.Controls.Add(this.progressBar1);
            this.Controls.Add(this.webBrowser1);
            this.Controls.Add(this.btn_Refresh);
            this.Controls.Add(this.btn_Go);
            this.Name = "Form1";
            this.Text = "Form1";
            this.ResumeLayout(false);
            this.PerformLayout();

        }

        #endregion

        private System.Windows.Forms.Button btn_Go;
        private System.Windows.Forms.Button btn_Refresh;
        private System.Windows.Forms.WebBrowser webBrowser1;
        private System.Windows.Forms.ProgressBar progressBar1;
        private System.Windows.Forms.TextBox txt_StatusBox;
        private System.Windows.Forms.Label lbl_StatusTxt;
        private System.Windows.Forms.ComboBox cbo_AddressBar;
        private System.Windows.Forms.Label label2;
        private System.Windows.Forms.Label label1;
        #endregion

        #region form.cs file
       
        public ProgressBrowser()
        {
            InitializeComponent();
            Initialize_this();
            this.Load += new EventHandler(Form1_Load);
        }

        #region Initialize Methods
        private void Initialize_this() // Template Method Pattern
        {
            this.Initialize_WebBrowser();
            this.Initialize_ProgressBar();
            this.Initialize_AddressBar();
            return;
        }

        private void Initialize_WebBrowser()
        {
            this.webBrowser1.DocumentCompleted +=
                new WebBrowserDocumentCompletedEventHandler(webBrowser1_DocumentCompleted);
            this.webBrowser1.ProgressChanged +=
                new WebBrowserProgressChangedEventHandler(webBrowser1_ProgressChanged);
            this.webBrowser1.Navigated +=
                new WebBrowserNavigatedEventHandler(webBrowser1_Navigated);
            this.webBrowser1.Navigating +=
                new WebBrowserNavigatingEventHandler(webBrowser1_Navigating);
            this.webBrowser1.StatusTextChanged += new EventHandler(webBrowser1_StatusTextChanged);
            return;
        }

        private void Initialize_ProgressBar()
        {
            this.progressBar1.Style = ProgressBarStyle.Continuous;
            this.progressBar1.Step = 10;
            return;
        }

        private void Initialize_AddressBar()
        {
            this.cbo_AddressBar.SelectedIndexChanged +=
                new EventHandler(cbo_AddressBar_SelectedIndexChanged);
        }

        #endregion

        #region Private Methods
        private void Navigate(Uri uri)
        {
            this.webBrowser1.Url = uri;
            URL_Add(uri);
            this.cbo_AddressBar.Text = uri.ToString();
            this.progressBar1.PerformStep();
        }

        private void URL_Add(Uri uri)
        {
            if (!this.cbo_AddressBar.Items.Contains(uri))
            {
                this.cbo_AddressBar.Items.Add(uri);
            }
        }
        #endregion

        #region Event Handlers
        void Form1_Load(
            object sender,
            EventArgs e)
        {
            this.Navigate(new Uri(HomePage));
            return;
        }

        private void btn_Go_Click(
            object sender,
            EventArgs e)
        {
            this.Navigate(new Uri(this.cbo_AddressBar.Text));
        }

        private void btn_Refresh_Click(
            object sender,
            EventArgs e)
        {
            this.Navigate(new Uri(this.cbo_AddressBar.Text));
        }

        private void webBrowser1_DocumentCompleted(
            object sender,
            WebBrowserDocumentCompletedEventArgs e)
        {
            switch (this.webBrowser1.ReadyState)
            {
                case WebBrowserReadyState.Complete:
                    //this.progressBar1.Value = this.progressBar1.Maximum;
                    this.progressBar1.Visible = false;
                    this.label1.Text = "totalProgress";
                    this.label2.Text = "currentProgress";
                    break;
                case WebBrowserReadyState.Interactive:
                    //this.progressBar1.PerformStep();
                    break;
                case WebBrowserReadyState.Loaded:
                    //this.progressBar1.PerformStep();
                    break;
                case WebBrowserReadyState.Loading:
                    //this.progressBar1.PerformStep();
                    break;
                case WebBrowserReadyState.Uninitialized:
                    //this.progressBar1.Value = this.progressBar1.Minimum;
                    this.progressBar1.Visible = false;
                    break;
                default:
                    break;
            }
            return;
        }
       
        private void webBrowser1_ProgressChanged(
            object sender,
            WebBrowserProgressChangedEventArgs e)
        {
            long progress = e.CurrentProgress;
            //
            if (e.CurrentProgress > 0)
            {
                this.currentProgress = (int)progress;
                this.label2.Text = e.CurrentProgress.ToString();
                this.label1.Text = e.MaximumProgress.ToString();
            }
            this.txt_StatusBox.Text = this.webBrowser1.ReadyState.ToString();
            if (this.webBrowser1.IsBusy)
            {
                try
                {
                    this.progressBar1.Maximum = (int)e.MaximumProgress;
                }
                catch (Exception ex)
                {
                    string msg = ex.Message;
                    this.progressBar1.Maximum = Int32.MaxValue;
                }
                if (e.CurrentProgress <= e.MaximumProgress)
                {
                    this.progressBar1.Value = (int)progress;
                }
            }
            else
            {
                this.progressBar1.Value = this.progressBar1.Minimum;
            }
            return;
        }

        private void webBrowser1_Navigated(
            object sender,
            WebBrowserNavigatedEventArgs e)
        {
            this.cbo_AddressBar.Text = this.webBrowser1.Url.ToString();
            this.URL_Add(this.webBrowser1.Url);
            return;
        }
       
        private void webBrowser1_Navigating(
            object sender,
            WebBrowserNavigatingEventArgs e)
        {
            this.progressBar1.Visible = true;
            return;
        }

        private void webBrowser1_StatusTextChanged(
            object sender,
            EventArgs e)
        {
            this.lbl_StatusTxt.Text = this.webBrowser1.StatusText;
            return;
        }

        private void cbo_AddressBar_SelectedIndexChanged(
            object sender,            
            EventArgs e)
        {
            Uri selectedURL = (Uri)this.cbo_AddressBar.SelectedItem;
            this.Navigate(selectedURL);
            return;
        }
        #endregion

        private string HomePage = @"http://www.microsoft.com/";
        private int currentProgress = 1;

        #endregion

    }

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