一种快速而肮脏的方法是使用 WinForms WebBrowser 控件并将其绘制到位图上。在独立的控制台应用程序中执行此操作有点棘手，因为您必须了解在使用基本异步编程模式时托管STAThread 控件的含义。但这里有一个工作概念证明，它将网页捕获为 800x600 BMP 文件：
namespace WebBrowserScreenshotSample
{
using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.Threading;
using System.Windows.Forms;
class Program
{
[STAThread]
static void Main()
{
int width = 800;
int height = 600;
using (WebBrowser browser = new WebBrowser())
{
browser.Width = width;
browser.Height = height;
browser.ScrollBarsEnabled = true;
// This will be called when the page finishes loading
browser.DocumentCompleted += Program.OnDocumentCompleted;
browser.Navigate("https://stackoverflow.com/");
// This prevents the application from exiting until
// Application.Exit is called
Application.Run();
}
}
static void OnDocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
{
// Now that the page is loaded, save it to a bitmap
WebBrowser browser = (WebBrowser)sender;
using (Graphics graphics = browser.CreateGraphics())
using (Bitmap bitmap = new Bitmap(browser.Width, browser.Height, graphics))
{
Rectangle bounds = new Rectangle(0, 0, bitmap.Width, bitmap.Height);
browser.DrawToBitmap(bitmap, bounds);
bitmap.Save("screenshot.bmp", ImageFormat.Bmp);
}
// Instruct the application to exit
Application.Exit();
}
}
}
要编译它，创建一个新的控制台应用程序并确保为System.Drawing 和System.Windows.Forms 添加程序集引用。
更新：我重写了代码以避免不得不使用 hacky 轮询 WaitOne/DoEvents 模式。此代码应该更接近于遵循最佳实践。
更新 2：您表示要在 Windows 窗体应用程序中使用它。在这种情况下，忘记动态创建WebBrowser 控件。您想要的是在您的表单上创建 WebBrowser 的隐藏 (Visible=false) 实例，并按照我上面显示的方式使用它。这是另一个示例，它显示了带有文本框 (webAddressTextBox)、按钮 (generateScreenshotButton) 和隐藏浏览器 (webBrowser) 的表单的用户代码部分。在我处理这个问题时，我发现了一个我以前没有处理过的特性—— DocumentCompleted 事件实际上可以根据页面的性质多次引发。这个示例应该可以正常工作，你可以扩展它来做任何你想做的事情：
namespace WebBrowserScreenshotFormsSample
{
using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Windows.Forms;
public partial class MainForm : Form
{
public MainForm()
{
this.InitializeComponent();
// Register for this event; we'll save the screenshot when it fires
this.webBrowser.DocumentCompleted +=
new WebBrowserDocumentCompletedEventHandler(this.OnDocumentCompleted);
}
private void OnClickGenerateScreenshot(object sender, EventArgs e)
{
// Disable button to prevent multiple concurrent operations
this.generateScreenshotButton.Enabled = false;
string webAddressString = this.webAddressTextBox.Text;
Uri webAddress;
if (Uri.TryCreate(webAddressString, UriKind.Absolute, out webAddress))
{
this.webBrowser.Navigate(webAddress);
}
else
{
MessageBox.Show(
"Please enter a valid URI.",
"WebBrowser Screenshot Forms Sample",
MessageBoxButtons.OK,
MessageBoxIcon.Exclamation);
// Re-enable button on error before returning
this.generateScreenshotButton.Enabled = true;
}
}
private void OnDocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
{
// This event can be raised multiple times depending on how much of the
// document has loaded, if there are multiple frames, etc.
// We only want the final page result, so we do the following check:
if (this.webBrowser.ReadyState == WebBrowserReadyState.Complete &&
e.Url == this.webBrowser.Url)
{
// Generate the file name here
string screenshotFileName = Path.GetFullPath(
"screenshot_" + DateTime.Now.Ticks + ".png");
this.SaveScreenshot(screenshotFileName);
MessageBox.Show(
"Screenshot saved to '" + screenshotFileName + "'.",
"WebBrowser Screenshot Forms Sample",
MessageBoxButtons.OK,
MessageBoxIcon.Information);
// Re-enable button before returning
this.generateScreenshotButton.Enabled = true;
}
}
private void SaveScreenshot(string fileName)
{
int width = this.webBrowser.Width;
int height = this.webBrowser.Height;
using (Graphics graphics = this.webBrowser.CreateGraphics())
using (Bitmap bitmap = new Bitmap(width, height, graphics))
{
Rectangle bounds = new Rectangle(0, 0, width, height);
this.webBrowser.DrawToBitmap(bitmap, bounds);
bitmap.Save(fileName, ImageFormat.Png);
}
}
}
}