思路其实很简单，直接通过document.documentElement.outerHTML
或者使用IPersistStreamInit接口直接对流进行处理
前者我就不废话了，后者实现方法如下
首先是写入HTML到已初始化的WebBrowser控件
初始化可以通过Navigate("about:blank")完成
必须确保WebBrowser.Document != null
否则应该推迟到DocumentComplete事件再读写
UCOMIStream stream = null;
CreateStreamOnHGlobal(Marshal.StringToHGlobalUni(value), true, out stream);
if(stream != null)
{
IPersistStreamInit persistentStreamInit =
(IPersistStreamInit)WebBrowser.Document;
persistentStreamInit.InitNew();
persistentStreamInit.Load(stream);
persistentStreamInit = null;
}
UCOMIStream是COM中IStream的CLR版本
CreateStreamOnHGlobal函数从一个字符串的地址
创建一个IStream供使用
[DllImport("ole32.dll", PreserveSig=false)]
static extern void CreateStreamOnHGlobal(IntPtr hGlobal,
Boolean fDeleteOnRelease, [Out] out UCOMIStream pStream);
然后就是通过IPersistStreamInit接口初始化并载入HTML源码，
IPersistStreamInit接口CLR缺省没有导入，定义如下
[ComVisible(true), ComImport(), Guid("7FD52380-4E07-101B-AE2D-08002B2EC713"),
InterfaceTypeAttribute(ComInterfaceType.InterfaceIsIUnknown)]
public interface IPersistStreamInit
{
void GetClassID([In, Out] ref Guid pClassID);
[return: MarshalAs(UnmanagedType.I4)] [PreserveSig]
int IsDirty();
void Load([In, MarshalAs(UnmanagedType.Interface)] UCOMIStream pstm);
void Save([In, MarshalAs(UnmanagedType.Interface)] UCOMIStream pstm,
[In, MarshalAs(UnmanagedType.I4)] int fClearDirty);
void GetSizeMax([Out, MarshalAs(UnmanagedType.LPArray)] long pcbSize);
void InitNew();
}
读取HTML也是类似思路，将HTML源码写到一个IStream中
然后转换成字符串供C#代码使用，不过实现方式比较麻烦
比较简单的方法还是使用ole32.dll提供的函数
重建流，但这需要预先设定流的长度，如
UCOMIStream stream = null;
CreateStreamOnHGlobal(Marshal.AllocHGlobal(4096), true, out stream);
IPersistStreamInit persistentStreamInit =
(IPersistStreamInit)WebBrowser.Document;
persistentStreamInit.Save(stream, 0);
persistentStreamInit = null;
IntPtr pStr;
GetHGlobalFromStream(stream, out pStr);
return Marshal.PtrToStringAnsi(pStr);
然后使用GetHGlobalFromStream函数和
Marshal.PtrToStringAnsi将流转换为字符串
另外一种方法是自行实现一个支持IStream接口的类
通过流的方式灵活完成读取操作，我比较喜欢这种
using(MemoryStream stream = new MemoryStream())
{
ComStreamAdapter adapter = new ComStreamAdapter(stream);
IPersistStreamInit persistentStreamInit =
(IPersistStreamInit)WebBrowser.Document;
persistentStreamInit.Save(adapter, 0);
stream.Seek(0, SeekOrigin.Begin);
using(StreamReader reader = new StreamReader(stream))
{
return reader.ReadToEnd();
}
}
这里的ComStreamAdapter是一个使用了adapter模式的类
将普通的System.IO.Stream转换为IStream支持的类
public class ComStreamAdapter : UCOMIStream
{
private Stream _stream;
public ComStreamAdapter(Stream stream)
{
_stream = stream;
}
#region UCOMIStream Members
public void Commit(int grfCommitFlags)
{
}
public void Clone(out UCOMIStream ppstm)
{
ppstm = null;
}
public void CopyTo(UCOMIStream pstm, long cb, System.IntPtr pcbRead, System.IntPtr pcbWritten)
{
}
public void Revert()
{
}
public void LockRegion(long libOffset, long cb, int dwLockType)
{
}
public void UnlockRegion(long libOffset, long cb, int dwLockType)
{
}
public void Seek(long dlibMove, int dwOrigin, System.IntPtr plibNewPosition)
{
_stream.Seek(dlibMove, (SeekOrigin)dwOrigin);
if(plibNewPosition != IntPtr.Zero)
{
Marshal.WriteInt32(plibNewPosition, (int)_stream.Position);
}
}
public void Read(byte[] pv, int cb, System.IntPtr pcbRead)
{
int size = _stream.Read(pv, (int)_stream.Position, cb);
if(pcbRead != IntPtr.Zero)
{
Marshal.WriteInt32(pcbRead, size);
}
}
public void Write(byte[] pv, int cb, System.IntPtr pcbWritten)
{
_stream.Write(pv, 0, cb);
if(pcbWritten != IntPtr.Zero)
{
Marshal.WriteInt32(pcbWritten, cb);
}
}
public void SetSize(long libNewSize)
{
_stream.SetLength(libNewSize);
}
public void Stat(out STATSTG pstatstg, int grfStatFlag)
{
pstatstg = new STATSTG ();
}
#endregion
} |
