如何使用表单身份验证将 .aspx 转换为 asp.net 中的图像答案

【问题标题】：How to convert .aspx to Image in asp.net with forms authentication如何使用表单身份验证将 .aspx 转换为 asp.net 中的图像
【发布时间】：2014-05-31 12:34:27
【问题描述】：

我试过这个代码

    public System.Drawing.Bitmap CaptureWebPage(string URL)
    {
        // create a hidden web browser, which will navigate to the page
        System.Windows.Forms.WebBrowser web = new System.Windows.Forms.WebBrowser();
        // we don't want scrollbars on our image
        web.ScrollBarsEnabled = false;
        // don't let any errors shine through
        web.ScriptErrorsSuppressed = true;
        // let's load up that page!
        web.Navigate(URL);

        // wait until the page is fully loaded
        while (web.ReadyState != WebBrowserReadyState.Complete)
            System.Windows.Forms.Application.DoEvents();
        System.Threading.Thread.Sleep(1500); // allow time for page scripts to update
        // the appearance of the page

        // set the size of our web browser to be the same size as the page
        int width = web.Document.Body.ScrollRectangle.Width;
        int height = web.Document.Body.ScrollRectangle.Height;
        web.Width = width;
        web.Height = height;
        // a bitmap that we will draw to
        System.Drawing.Bitmap bmp = new System.Drawing.Bitmap(width, height);
        // draw the web browser to the bitmap
        web.DrawToBitmap(bmp, new System.Drawing.Rectangle(0, 0, width, height));

        return bmp; // return the bitmap for processing
    }
    protected void btnConvert_Click(object sender, EventArgs e)
    {
        Bitmap bitmap = new Bitmap(CaptureWebPage(txtUrl.Text));
        Response.ContentType = "image/jpeg";
        bitmap.Save(Response.OutputStream, ImageFormat.Jpeg);
        bitmap.Dispose();
        bitmap.Dispose();
        Response.End();
    }

我能够捕获 google.com，但无法捕获我们网站的图像，因为它包含表单身份验证，因此它将我重定向到登录页面并捕获登录页面。请帮助通过身份验证。我们可以使用会话、cookie 或任何与 WebBrowser 一起验证它的东西。请提出建议。

【问题讨论】：

标签： html asp.net image converter

【解决方案1】：

在您网站上的预期页面上尝试：

        System.Text.StringBuilder sb = new System.Text.StringBuilder();
        System.IO.StringWriter sw = new System.IO.StringWriter(sb);
        Page.RenderControl(new HtmlTextWriter(sw));

然后使用字符串生成器中的 HTML 来呈现页面，如下例所示（参考：Convert HTML string to image）：

using System;
using System.Drawing;
using System.Threading;
using System.Windows.Forms;

    class Program
    {
        static void Main(string[] args)
        {
            var source =  @"
            <!DOCTYPE html>
            <html>
                <body>
                    <p>An image from W3Schools:</p>
                    <img 
                        src=""http://www.w3schools.com/images/w3schools_green.jpg"" 
                        alt=""W3Schools.com"" 
                        width=""104"" 
                        height=""142"">
                </body>
            </html>";
            StartBrowser(source);
            Console.ReadLine();
        }

        private static void StartBrowser(string source)
        {
            var th = new Thread(() =>
            {
                var webBrowser = new WebBrowser();
                webBrowser.ScrollBarsEnabled = false;
                webBrowser.DocumentCompleted +=
                    webBrowser_DocumentCompleted;
                webBrowser.DocumentText = source;
                Application.Run();
            });
            th.SetApartmentState(ApartmentState.STA);
            th.Start();
        }

        static void 
            webBrowser_DocumentCompleted(
            object sender, 
            WebBrowserDocumentCompletedEventArgs e)
        {
            var webBrowser = (WebBrowser)sender;
            using (Bitmap bitmap = 
                new Bitmap(
                    webBrowser.Width, 
                    webBrowser.Height))
            {
                webBrowser
                    .DrawToBitmap(
                    bitmap, 
                    new System.Drawing
                        .Rectangle(0, 0, bitmap.Width, bitmap.Height));
                bitmap.Save(@"filename.jpg", 
                    System.Drawing.Imaging.ImageFormat.Jpeg);
            }
        }
    }

【讨论】：