如何在使用列表时循环 HTML 打印

本文关键字：循环 HTML 打印 列表 | 更新日期: 2023-09-27 18:31:31

>我有一个列表，其中包含我电脑上html文件的路径。我想循环浏览此列表并按照它们在列表中的相同顺序打印它们。

我试图循环我在 msdn.microsoft.com 上找到的代码来打印HTML文件。

List<string> AllHTMLsToPrint = new List<string>();
//things added to AllHTMLsToPrint list
foreach (string strHTMLToPrint in AllHTMLsToPrint)
{
    PrintHelpPage(strHTMLToPrint);
}
private void PrintHelpPage(string strHTMLToPrint)
{
    // Create a WebBrowser instance. 
    WebBrowser webBrowserForPrinting = new WebBrowser();
    // Add an event handler that prints the document after it loads.
    webBrowserForPrinting.DocumentCompleted +=
        new WebBrowserDocumentCompletedEventHandler(PrintDocument);
    // Set the Url property to load the document.
    webBrowserForPrinting.Url = new Uri(strHTMLToPrint);
    Thread.Sleep(100);
}
private void PrintDocument(object sender, WebBrowserDocumentCompletedEventArgs e)
{
    // Print the document now that it is fully loaded.
    ((WebBrowser)sender).Print();
    // Dispose the WebBrowser now that the task is complete. 
    ((WebBrowser)sender).Dispose();
}

如何在使用列表时循环 HTML 打印

你这里有一个设计问题。您浏览要打印的 html 页面列表。然后在浏览器中打开该页面。加载页面后，您可以打印它。

但。。。

加载页面可能需要超过 100 毫秒的时间。这是浏览器加载下一页的时间。您应该更改代码，以便在打印当前页面后加载下一页。在这种情况下，您可能不想使用循环，而是要在打印后增加索引。

应该看起来与此类似（未测试）：

List<string> AllHTMLsToPrint = new List<string>();
private int index = 0;
PrintHelpPage(AllHTMLsToPrint[index]);

private void PrintHelpPage(string strHTMLToPrint)
{
    // Create a WebBrowser instance. 
    WebBrowser webBrowserForPrinting = new WebBrowser();
    // Add an event handler that prints the document after it loads.
    webBrowserForPrinting.DocumentCompleted +=
        new WebBrowserDocumentCompletedEventHandler(PrintDocument);
    // Set the Url property to load the document.
    webBrowserForPrinting.Url = new Uri(strHTMLToPrint);
}
private void PrintDocument(object sender, WebBrowserDocumentCompletedEventArgs e)
{
    // Print the document now that it is fully loaded.
    ((WebBrowser)sender).Print();
    if (index < AllHTMLsToPrint.Count -1)
    PrintHelpPage(AllHTMLsToPrint[++index]);
}

你已经说过你有一堆本地html文件。通过设置 URI，加载本地 html 文件可能无法正常工作。您可以尝试设置文档流。strHTMLToPrint 必须包含本地 html 文件的完整/相对路径。

webBrowserForPrinting.DocumentStream = File.OpenRead(strHTMLToPrint);

不确定确切的问题是什么，但我会把它放到后台工作线程中，这样你就不会阻止主线程。 我还会将循环移动到文档加载系统中，这样一旦它加载并打印出来，它就会移动到下一个循环。

也就是说，你还没有说你的代码没有做什么。

public partial class Form1 : Form
{
    internal List<string> AllHTMLsToPrint = new List<string>();
    public Form1()
    {
        InitializeComponent();
    }
    public void StartPrinting()
    {
        //things added to AllHTMLsToPrint list, please note you may need to add file:/// to the URI list if it is a local file, unless it is compact framework
        // start printing the first item
        BackgroundWorker bgw = new BackgroundWorker();
        bgw.DoWork += bgw_DoWork;
        bgw.RunWorkerAsync();
        /*foreach (string strHTMLToPrint in AllHTMLsToPrint)
        {
            PrintHelpPage(strHTMLToPrint);
        }*/
    }
    void bgw_DoWork(object sender, DoWorkEventArgs e)
    {
        PrintHelpPage(AllHTMLsToPrint[0], (BackgroundWorker)sender);
    }
    private void PrintHelpPage(string strHTMLToPrint, BackgroundWorker bgw)
    {
        // Create a WebBrowser instance. 
        WebBrowser webBrowserForPrinting = new WebBrowser();
        // Add an event handler that prints the document after it loads.
        webBrowserForPrinting.DocumentCompleted += (s, ev) => {
            webBrowserForPrinting.Print();
            webBrowserForPrinting.Dispose();
            // you can add progress reporting here
            // remove the first element and see if we have to do it all again
            AllHTMLsToPrint.RemoveAt(0);
            if (AllHTMLsToPrint.Count > 0)
                PrintHelpPage(AllHTMLsToPrint[0], bgw);
        };

        // Set the Url property to load the document.
        webBrowserForPrinting.Url = new Uri(strHTMLToPrint);
    }
}
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