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  • C#教程之Winform实现将网页生成图片的方法

通常浏览器都有将网页生成图片的功能，本文实例讲述了Winform实现将网页生成图片的方法。分享给大家供大家参考。具体方法如下：

工具截图如下：

生成后的图片如下：

手动填写网站地址，可选择图片类型和保持图片地址，来生成页面的图片，当图片路径未选择时则保存桌面；

具体代码如下：

将html生成图片的类

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using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Drawing.Imaging;
using System.Runtime.InteropServices;
using System.Security;
namespace Print
{
  public class Test
  {
    public static Bitmap GetHtmlImage(Uri UrlString, int Width)
    {
      WebBrowser MyControl = new WebBrowser();
      MyControl.Size = new Size(Width, 10);
      MyControl.Url = UrlString;
      while (MyControl.ReadyState != WebBrowserReadyState.Complete)
      {
        Application.DoEvents();
      }
      MyControl.Height = MyControl.Document.Body.ScrollRectangle.Height + 20;
      MyControl.Url = UrlString;
      WebControlImage.Snapshot snap = new WebControlImage.Snapshot();
      Bitmap MyImage = snap.TakeSnapshot(MyControl.ActiveXInstance, new Rectangle(0, 0, MyControl.Width, MyControl.Height));
      MyControl.Dispose();
      return MyImage;
    }
    ///
    /// WebBrowser获取图形
    ///
    private class WebControlImage
    {
      internal static class NativeMethods
      {
        [StructLayout(LayoutKind.Sequential)]
        public sealed class tagDVTARGETDEVICE
        {
          [MarshalAs(UnmanagedType.U4)]
          public int tdSize;
          [MarshalAs(UnmanagedType.U2)]
          public short tdDriverNameOffset;
          [MarshalAs(UnmanagedType.U2)]
          public short tdDeviceNameOffset;
          [MarshalAs(UnmanagedType.U2)]
          public short tdPortNameOffset;
          [MarshalAs(UnmanagedType.U2)]
          public short tdExtDevmodeOffset;
        }
        [StructLayout(LayoutKind.Sequential)]
        public class COMRECT
        {
          public int left;
          public int top;
          public int right;
          public int bottom;
          public COMRECT()
          {
          }
          public COMRECT(Rectangle r)
          {
            this.left = r.X;
            this.top = r.Y;
            this.right = r.Right;
            this.bottom = r.Bottom;
          }
          public COMRECT(int left, int top, int right, int bottom)
          {
            this.left = left;
            this.top = top;
            this.right = right;
            this.bottom = bottom;
          }
          public static NativeMethods.COMRECT FromXYWH(int x, int y, int width, int height)
          {
            return new NativeMethods.COMRECT(x, y, x + width, y + height);
          }
          public override string ToString()
          {
            return string.Concat(new object[] { "Left = ", this.left, " Top ", this.top, " Right = ", this.right, " Bottom = ", this.bottom });
          }
        }
        [StructLayout(LayoutKind.Sequential)]
        public sealed class tagLOGPALETTE
        {
          [MarshalAs(UnmanagedType.U2)]
          public short palVersion;
          [MarshalAs(UnmanagedType.U2)]
          public short palNumEntries;
        }
      }
      public class Snapshot
      {
        ///
        /// ?煺?
        ///
        /// Com 对象
        /// 图象大小
        ///
        public Bitmap TakeSnapshot(object pUnknown, Rectangle bmpRect)
        {
          if (pUnknown == null)
            return null;
          //必须为com对象
          if (!Marshal.IsComObject(pUnknown))
            return null;
          //IViewObject 接口
          UnsafeNativeMethods.IViewObject ViewObject = null;
          IntPtr pViewObject = IntPtr.Zero;
          //内存图
          Bitmap pPicture = new Bitmap(bmpRect.Width, bmpRect.Height);
          Graphics hDrawDC = Graphics.FromImage(pPicture);
          //获取接口
          object hret = Marshal.QueryInterface(Marshal.GetIUnknownForObject(pUnknown),
          ref UnsafeNativeMethods.IID_IViewObject, out pViewObject);
          try
          {
            ViewObject = Marshal.GetTypedObjectForIUnknown(pViewObject, typeof(UnsafeNativeMethods.IViewObject)) as UnsafeNativeMethods.IViewObject;
            //调用Draw方法
            ViewObject.Draw((int)System.Runtime.InteropServices.ComTypes.DVASPECT.DVASPECT_CONTENT,
            -1,
            IntPtr.Zero,
            null,
            IntPtr.Zero,
            hDrawDC.GetHdc(),
            new NativeMethods.COMRECT(bmpRect),
            null,
            IntPtr.Zero,
            0);
          }
          catch (Exception ex)
          {
            Console.WriteLine(ex.Message);
            throw ex;
          }
          //释放
          hDrawDC.Dispose();
          return pPicture;
        }
      }
      [SuppressUnmanagedCodeSecurity]
      internal static class UnsafeNativeMethods
      {
        public static Guid IID_IViewObject = new Guid("{0000010d-0000-0000-C000-000000000046}");
        [ComImport, Guid("0000010d-0000-0000-C000-000000000046"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
        public interface IViewObject
        {
          [PreserveSig]
          int Draw([In, MarshalAs(UnmanagedType.U4)] int dwDrawAspect, int lindex, IntPtr pvAspect, [In] NativeMethods.tagDVTARGETDEVICE ptd, IntPtr hdcTargetDev, IntPtr hdcDraw, [In] NativeMethods.COMRECT lprcBounds, [In] NativeMethods.COMRECT lprcWBounds, IntPtr pfnContinue, [In] int dwContinue);
          [PreserveSig]
          int GetColorSet([In, MarshalAs(UnmanagedType.U4)] int dwDrawAspect, int lindex, IntPtr pvAspect, [In] NativeMethods.tagDVTARGETDEVICE ptd, IntPtr hicTargetDev, [Out] NativeMethods.tagLOGPALETTE 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);
          void SetAdvise([In, MarshalAs(UnmanagedType.U4)] int aspects, [In, MarshalAs(UnmanagedType.U4)] int advf, [In, MarshalAs(UnmanagedType.Interface)] System.Runtime.InteropServices.ComTypes.IAdviseSink pAdvSink);
          void GetAdvise([In, Out, MarshalAs(UnmanagedType.LPArray)] int[] paspects, [In, Out, MarshalAs(UnmanagedType.LPArray)] int[] advf, [In, Out, MarshalAs(UnmanagedType.LPArray)] System.Runtime.InteropServices.ComTypes.IAdviseSink[] pAdvSink);
        }
      }
    }
  }
}

winfrom后台处理方面代码如下

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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.Drawing.Imaging;
 
namespace Excel文件处理
{
  public partial class Html : Form
  {
    public Html()
    {
      InitializeComponent();
    }
    private string ImageUrl = "";//图片地址
    private string ImageName = "";//图片名称
    private void button1_Click(object sender, EventArgs e)
    {
      string HtmlUrl = this.Txt_Url.Text.Trim();
      if (HtmlUrl=="")
      {
        MessageBox.Show("请输入网址");
        return;
      }
      if (ImageUrl.Trim()=="")
      {
        ImageUrl = @"C:\Users\Administrator\Desktop"; 
      }
      try
      {
        Uri ri = new Uri(this.Txt_Url.Text);
        Bitmap bit = Print.Test.GetHtmlImage(ri, 1200);
        ImageName = this.Txt_Name.Text.Trim();//图片名称
        if (ImageName != "")
        {
          if (ImageName.IndexOf('.') != -1)
          {//当用户输入图片后缀时，将后缀截取
            ImageName.Substring(0, ImageName.LastIndexOf('.'));
          }
        }
        else
          ImageName = DateTime.Now.Ticks.ToString();//时间名称
        switch (this.comboBox1.SelectedText)
        {
          case "GIF": ImageUrl += "\\" + ImageName + ".gif"; break;
          case "JPG": ImageUrl += "\\" + ImageName + ".jpg"; break;
          case "PNG": ImageUrl += "\\" + ImageName + ".png"; break;
          default: ImageUrl += "\\" + ImageName + ".png"; break;
        }
 
        switch (this.comboBox1.SelectedText)
        {
          case "GIF": bit.Save(ImageUrl, ImageFormat.Gif); break;
          case "JPG": bit.Save(ImageUrl, ImageFormat.Jpeg); break;
          case "PNG": bit.Save(ImageUrl, ImageFormat.Png); break;
          default: bit.Save(ImageUrl, ImageFormat.Png); break;
        }
 
        bit = null;
        ImageUrl = "";//图片地址
        ImageName = "";//图片名称
        MessageBox.Show("生产成功");
      }
      catch
      {
        MessageBox.Show("网址输入有误！");
        return;
      }
    }
 
    private void button2_Click(object sender, EventArgs e)
    {
      //获取保存路径
      if (this.folderBrowserDialog1.ShowDialog()==DialogResult.OK)
      {
        if (this.folderBrowserDialog1.SelectedPath.Trim()!="")
        {
          ImageUrl = folderBrowserDialog1.SelectedPath;
          this.label6.Text = ImageUrl;
        }
      }
    }
  }
}

希望本文所述对大家的C#程序设计有所帮助。


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