我正在尝试使用标准 c# .net 代码捕获以下页面。我搜索了人们的各种方法，其中大部分涉及实例化浏览器对象和使用绘制位图方法。但是，这些都没有获取此页面上图表的内容：
http://www.highcharts.com/demo/combo-dual-axes
也许 javascript 没有时间运行，但添加 Thread.Sleep(x) 并没有帮助。
这个commercial component 正确捕获了它，但我宁愿避免在我的项目中需要额外的依赖项，并且在其他解决方案非常接近时支付 150 美元！。
有人发现他们的解决方案可以正确呈现这个吗？
【问题讨论】：
标签： c# javascript .net highcharts
您可能已经尝试过IECapt。我认为这是正确的方法。我创建了它的修改版本并使用 timer 而不是 Thread.Sleep 它可以按预期捕获您的网站。
-----编辑------
这是丑陋的来源。只需添加对Microsoft HTML Object Library 的引用即可。
这是用法：
HtmlCapture capture = new HtmlCapture(@"c:\temp\myimg.png");
capture.HtmlImageCapture += new HtmlCapture.HtmlCaptureEvent(capture_HtmlImageCapture);
capture.Create("http://www.highcharts.com/demo/combo-dual-axes");
void capture_HtmlImageCapture(object sender, Uri url)
{
this.Close();
}
文件1
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.IO;
namespace MyIECapt
{
public class HtmlCapture
{
private WebBrowser web;
private Timer tready;
private Rectangle screen;
private Size? imgsize = null;
//an event that triggers when the html document is captured
public delegate void HtmlCaptureEvent(object sender, Uri url);
public event HtmlCaptureEvent HtmlImageCapture;
string fileName = "";
//class constructor
public HtmlCapture(string fileName)
{
this.fileName = fileName;
//initialise the webbrowser and the timer
web = new WebBrowser();
tready = new Timer();
tready.Interval = 2000;
screen = Screen.PrimaryScreen.Bounds;
//set the webbrowser width and hight
web.Width = 1024; //screen.Width;
web.Height = 768; // screen.Height;
//suppress script errors and hide scroll bars
web.ScriptErrorsSuppressed = true;
web.ScrollBarsEnabled = false;
//attached events
web.Navigating +=
new WebBrowserNavigatingEventHandler(web_Navigating);
web.DocumentCompleted += new
WebBrowserDocumentCompletedEventHandler(web_DocumentCompleted);
tready.Tick += new EventHandler(tready_Tick);
}
public void Create(string url)
{
imgsize = null;
web.Navigate(url);
}
public void Create(string url, Size imgsz)
{
this.imgsize = imgsz;
web.Navigate(url);
}
void web_DocumentCompleted(object sender,
WebBrowserDocumentCompletedEventArgs e)
{
//start the timer
tready.Start();
}
void web_Navigating(object sender, WebBrowserNavigatingEventArgs e)
{
//stop the timer
tready.Stop();
}
void tready_Tick(object sender, EventArgs e)
{
try
{
//stop the timer
tready.Stop();
mshtml.IHTMLDocument2 docs2 = (mshtml.IHTMLDocument2)web.Document.DomDocument;
mshtml.IHTMLDocument3 docs3 = (mshtml.IHTMLDocument3)web.Document.DomDocument;
mshtml.IHTMLElement2 body2 = (mshtml.IHTMLElement2)docs2.body;
mshtml.IHTMLElement2 root2 = (mshtml.IHTMLElement2)docs3.documentElement;
// Determine dimensions for the image; we could add minWidth here
// to ensure that we get closer to the minimal width (the width
// computed might be a few pixels less than what we want).
int width = Math.Max(body2.scrollWidth, root2.scrollWidth);
int height = Math.Max(root2.scrollHeight, body2.scrollHeight);
//get the size of the document's body
Rectangle docRectangle = new Rectangle(0, 0, width, height);
web.Width = docRectangle.Width;
web.Height = docRectangle.Height;
//if the imgsize is null, the size of the image will
//be the same as the size of webbrowser object
//otherwise set the image size to imgsize
Rectangle imgRectangle;
if (imgsize == null) imgRectangle = docRectangle;
else imgRectangle = new Rectangle() { Location = new Point(0, 0), Size = imgsize.Value };
//create a bitmap object
Bitmap bitmap = new Bitmap(imgRectangle.Width, imgRectangle.Height);
//get the viewobject of the WebBrowser
IViewObject ivo = web.Document.DomDocument as IViewObject;
using (Graphics g = Graphics.FromImage(bitmap))
{
//get the handle to the device context and draw
IntPtr hdc = g.GetHdc();
ivo.Draw(1, -1, IntPtr.Zero, IntPtr.Zero,
IntPtr.Zero, hdc, ref imgRectangle,
ref docRectangle, IntPtr.Zero, 0);
g.ReleaseHdc(hdc);
}
//invoke the HtmlImageCapture event
bitmap.Save(fileName);
bitmap.Dispose();
}
catch
{
//System.Diagnostics.Process.GetCurrentProcess().Kill();
}
if(HtmlImageCapture!=null) HtmlImageCapture(this, web.Url);
}
}
}
和文件2
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Drawing;
using System.Runtime.InteropServices;
namespace MyIECapt
{
[ComVisible(true), ComImport()]
[GuidAttribute("0000010d-0000-0000-C000-000000000046")]
[InterfaceTypeAttribute(ComInterfaceType.InterfaceIsIUnknown)]
public interface IViewObject
{
[return: MarshalAs(UnmanagedType.I4)]
[PreserveSig]
int Draw(
[MarshalAs(UnmanagedType.U4)] UInt32 dwDrawAspect,
int lindex,
IntPtr pvAspect,
[In] IntPtr ptd,
IntPtr hdcTargetDev,
IntPtr hdcDraw,
[MarshalAs(UnmanagedType.Struct)] ref Rectangle lprcBounds,
[MarshalAs(UnmanagedType.Struct)] ref Rectangle lprcWBounds,
IntPtr pfnContinue,
[MarshalAs(UnmanagedType.U4)] UInt32 dwContinue);
[PreserveSig]
int GetColorSet([In, MarshalAs(UnmanagedType.U4)] int dwDrawAspect,
int lindex, IntPtr pvAspect, [In] IntPtr ptd,
IntPtr hicTargetDev, [Out] IntPtr ppColorSet);
[PreserveSig]
int Freeze([In, MarshalAs(UnmanagedType.U4)] int dwDrawAspect,
int lindex, IntPtr pvAspect, [Out] IntPtr pdwFreeze);
[PreserveSig]
int Unfreeze([In, MarshalAs(UnmanagedType.U4)] int dwFreeze);
}
}
【讨论】：
Thread.Sleep 将简单地暂停您的 Web 浏览器正在运行的线程 - 您希望它在暂停时如何呈现任何内容？ :)
相反，您需要允许线程处理工作。您可以通过结合使用Thread.Sleep(0) 和Application.DoEvents() 来实现这一点，如下所示：
DateTime finish = DateTime.Now.AddSeconds(3);
while (DateTime.Now < finish) {
Application.DoEvents();
Thread.Sleep(0);
}
【讨论】：
@L.B，谢谢你的帮助！
对于任何想要在类库中运行它的人来说，仅供参考， WebBrowser 需要单线程单元，所以这样做：
var t = new Thread(InitAndDo); //InitAndDo would have your code creating the webbrowser object etc...
t.SetApartmentState(ApartmentState.STA);
t.Start();
然后Gotcha，在navigation调用完成后，添加这行代码，这样你就可以得到完成的导航事件：
web.Navigate(Url);
Application.Run();
【讨论】：
我为此创建了一个 nuget 包 https://github.com/dcumin39/RenderHighCharts/wiki
【讨论】：