C# WebBrowser.ShowPrintDialog() not showing

问题

I have this peculiar problem while wanting to print a html-report. The file itself is a normal local html file, located on my hard drive.

To do this, I have tried the following:

    public static void PrintReport(string path)
    {
        WebBrowser wb = new WebBrowser();
        wb.Navigate(path);
        wb.ShowPrintDialog()
    }

And I have this form with a button with the click event:

    private void button1_Click(object sender, EventArgs e)
    {
        string path = @"D:\MyReport.html";
        PrintReport(path);
    }

This does absolutely nothing. Which is kind of strange... but things get stranger...

When editing the print function to do the following:

    public static void PrintReport(string path)
    {
        WebBrowser wb = new WebBrowser();
        wb.Navigate(path);
        MessageBox.Show("TEST");
        wb.ShowPrintDialog()
    }

It works. Yes, only adding a MessageBox. The MessageBox is showing and after it comes the print dialog. I have also tried with Thread.Sleep(1000) instead, which doesn't work. Can anyone explain to me what's going on here? Why would a messagebox make any difference?

Can it be some kind of permission problem? I've reproduced this on both Windows 7 and 8, same thing. I made this small application with only the above code to isolate the problem. I am quite sure it works on windows XP though, since an older version of the application I'm working on runs on it. When trying to do this directly with the mshtml-dll instead I also get problems.

Any input or clarification is greatly appreciated!

回答1:

The problem is that the browser is not ready to print yet. You will want to add an event handler WebBrowserDocumentCompletedEventHandler to the WebBrowser Object. Sample code below.

public static void PrintReport(string path)
{
    WebBrowser wb = new WebBrowser();
    wb.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(webBrowser_DocumentCompleted);
    wb.Navigate(path);
}

public static void webBrowser_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
{
    WebBrowser wb = (WebBrowser)sender;
    if (wb.ReadyState.Equals(WebBrowserReadyState.Complete))
        wb.ShowPrintDialog();
}

来源：https://stackoverflow.com/questions/13827317/c-sharp-webbrowser-showprintdialog-not-showing

标签

html

printing