打印网页中特定内容

由于工作的需要，要求打印网页。而且是网页中的指定内容。有点多次一举“可是这就是客户的需求！！~”（某高人语）。收集了两个比较合适的解决方法。
首先是用JAVASCRIPT，以下是函数


<script language="javascript" type="text/javascript">


<!--






function Button3_onclick()

{


bdhtml=window.document.body.innerHTML;


sprnstr="<!--startprint-->";


eprnstr="<!--endprint-->";


prnhtml=bdhtml.substr(bdhtml.indexOf(sprnstr)+17);


prnhtml=prnhtml.substring(0,prnhtml.indexOf(eprnstr));


window.document.body.innerHTML=prnhtml;


window.print();




}


</script>

应用时把要打印的内容放到<!--startprint-->和<!--endprint-->之间。
二是C# documment类和print类的实现：


using System;


using System.ComponentModel;


using System.Collections;


using System.Drawing;


using System.Drawing.Printing;


using System.Globalization;


using System.IO;


using Print = System.Drawing.Printing.PrintDocument;




namespace Sanxing.NdtReprot.Internal






{




/**//// <summary>


/// 表示专用于大量文本打印的对象，该对象将输出至打印机。


/// </summary>


[Description("表示专用于大量文本打印的对象，该对象将输出至打印机。")]


internal sealed class TextPrintDocument : Print, IDisposable






{




私有变量#region 私有变量




private Font _printfont;


private Font _headerFooterFont;


private Pen _penHeaderFooterLine;


private PrintTextMode _printMode;


private bool _printLineNumbers;


private bool _printHeader;


private bool _printFooter;


private string _header;


private string _footer;


private TextReader _sr;


private ArrayList _buffer;


private bool _emptyBuffer;


private int _totalPageLines;


private int _currentPageLine;


private string _stringToPrint;


private int _currentPageNumber;


private int _currentLine;


private int _totalPrintedPages;


private const string DEFAULT_HEADER = "&n";


private const string DEFAULT_FOOTER = "&r&p";






private string[] _dateFormat =

{


"dddd", "ddd", "dd", "d", "D", "MMMM", "MMM", "MM", "m", "yyyy", "yy", "y", "f",


"F", "g", "G", "r", "s", "t", "T", "u", "U",


};




#endregion






属性#region 属性






/**//// <summary>


/// 设置要从中独取打印文本的 <see cref="Stream"/> 对象。


/// </summary>


[Category("内容"), Description("设置要从中独取打印文本的数据流。")]


internal Stream ContentStream






{


set






{


if(value != null)


_sr = new StreamReader(value);


}


}






/**//// <summary>


/// 获取或设置打印内容文本的字体。


/// </summary>


[Category("内容"), Description("获取或设置打印内容文本的字体。")]


internal Font BodyFont






{




get

{ return _printfont; }




set

{ _printfont = value; }


}






/**//// <summary>


/// 获取或设置打印页眉页脚文本的字体。


/// </summary>


[Category("内容"), Description("获取或设置打印页眉页脚文本的字体。")]


internal Font HeaderFooterFont






{




get

{ return _headerFooterFont; }




set

{ _headerFooterFont = value; }


}






/**//// <summary>


/// 获取或设置打印模式。


/// </summary>


[Category("内容"), Description("获取或设置打印模式。"), DefaultValue(PrintTextMode.WrapText)]


internal PrintTextMode PrintMode






{




get

{ return _printMode; }




set

{ _printMode = value; }


}






/**//// <summary>


/// 获取或设置每页打印的行数。


/// </summary>


[Category("内容"), Description("获取或设置每页打印的行数。")]


internal bool PrintLineNumber






{




get

{ return _printLineNumbers; }




set

{ _printLineNumbers = value; }


}






/**//// <summary>


/// 获取或设置一个值，该值指示是否打印页眉部分。


/// </summary>


[Category("内容"), Description("获取或设置一个值，该值指示是否打印页眉部分。"), DefaultValue(false)]


internal bool PrintHeader






{




get

{ return _printHeader; }




set

{ _printHeader = value; }


}






/**//// <summary>


/// 获取或设置一个值，该值指示是否打印页脚部分。


/// </summary>


[Category("内容"), Description("获取或设置一个值，该值指示是否打印页脚部分。"), DefaultValue(false)]


internal bool PrintFooter






{




get

{ return _printFooter; }




set

{ _printFooter = value; }


}






/**//// <summary>


/// 获取或设置要进行打印的文本。


/// </summary>


[Category("内容"), Description("获取或设置要进行打印的文本。")]


internal string Text






{




get

{ return _stringToPrint; }




set

{ _stringToPrint = value; }


}






/**//// <summary>


/// 获取或设置要打印在页眉部分的文本。


/// </summary>


[Description("获取或设置要打印在页眉部分的文本。"), DefaultValue(""), Category("内容")]


internal string Header






{




get

{ return _header; }




set

{ _header = value; }


}






/**//// <summary>


/// 获取或设置要打印在页脚部分的文本。


/// </summary>


[Category("内容"), Description("获取或设置要打印在页脚部分的文本。"), DefaultValue("")]


internal string Footer






{




get

{ return _footer; }




set

{ _footer = value; }


}




#endregion






构造器#region 构造器






/**//// <summary>


/// 使用默认值初始化 <b>TextPrintDocument</b> 类的新实例。


/// </summary>


public TextPrintDocument() : base()






{


_sr = null;


_stringToPrint = string.Empty;


_penHeaderFooterLine = Pens.Black;


_header = DEFAULT_HEADER;


_footer = DEFAULT_FOOTER;


}






/**//// <summary>


/// 使用内容流以及字体初始化<b>TextPrintDocument</b> 类的新实例。


/// </summary>


/// <param name="Stream"></param>


/// <param name="BodyFont"></param>


public TextPrintDocument(Stream Stream, Font BodyFont) :base()






{


if(Stream == null)


throw new ArgumentNullException("Stream");


_sr = new StreamReader(Stream);


if (BodyFont == null)


_printfont = new Font("宋体", 3.5f, FontStyle.Regular, GraphicsUnit.Millimeter);


else


_printfont = BodyFont;


_stringToPrint = string.Empty;


_penHeaderFooterLine = Pens.Black;


_header = DEFAULT_HEADER;


_footer = DEFAULT_FOOTER;


}






/**//// <summary>


///


/// </summary>


/// <param name="PrintText"></param>


/// <param name="BodyFont"></param>


public TextPrintDocument(string PrintText, Font BodyFont)


: base()






{


if(PrintText == null || PrintText == string.Empty)


throw new ArgumentNullException("PrintText");


_stringToPrint = PrintText;


_sr = null;


if (BodyFont == null)


_printfont = new Font("宋体", 3.5f, FontStyle.Regular, GraphicsUnit.Millimeter);


else


_printfont = BodyFont;


_penHeaderFooterLine = Pens.Black;


_header = DEFAULT_HEADER;


_footer = DEFAULT_FOOTER;


}




#endregion






方法#region 方法






/**//// <summary>


/// 在处理打印内容前，执行必要操作。


/// </summary>


/// <param name="e"></param>


protected override void OnBeginPrint(PrintEventArgs e)






{


base.OnBeginPrint(e);


if (_sr == null && _stringToPrint == string.Empty)


throw new InvalidOperationException("没有发现要进行打印处理的文档或数据流。");


// 检查是否有文本，有就生成读取器。


if (_stringToPrint != string.Empty)


_sr = new StringReader(_stringToPrint);


// 检查页眉页脚的字体


if (_headerFooterFont == null)


_headerFooterFont = _printfont;


_currentPageNumber = 0;


_totalPrintedPages = 0;


_currentLine = 1;


}






/**//// <summary>


/// 打印完毕后，执行必要操作。


/// </summary>


/// <param name="e"></param>


protected override void OnEndPrint(PrintEventArgs e)






{


base.OnEndPrint(e);


if(_sr != null)


_sr.Close();


_totalPrintedPages = _currentPageNumber;


}






/**//// <summary>


/// 在打印前，生成打印内容。


/// </summary>


/// <param name="e"></param>


protected override void OnPrintPage(PrintPageEventArgs e)






{


base.OnPrintPage(e);


Graphics gfx = e.Graphics;


PageSettings pageset = DefaultPageSettings; // 页面设置


float printAreaHeight = pageset.PaperSize.Height - (pageset.Margins.Top + pageset.Margins.Bottom);


float printAreaWidth = pageset.PaperSize.Width - (pageset.Margins.Left + pageset.Margins.Right);


float marginLeft = pageset.Margins.Left;


float marginTop = pageset.Margins.Top;


if(DefaultPageSettings.Landscape)






{


float tmp = printAreaHeight;


printAreaHeight = printAreaWidth;


printAreaWidth = tmp;


}


if(_buffer == null)


_buffer = new ArrayList(_totalPageLines);


float charHeight = _printfont.GetHeight(gfx);


float headerFooterCharHeight = _headerFooterFont.GetHeight(gfx);


float headerFooterHeight = headerFooterCharHeight + charHeight;


RectangleF rectHeader =


new RectangleF(marginLeft, marginTop, printAreaWidth, _printHeader ? headerFooterHeight : 0);


RectangleF rectFooter =


new RectangleF(marginLeft, marginTop + printAreaHeight, printAreaWidth,


_printFooter ? headerFooterHeight : 0);


if(_printHeader) // 检查是否要输出页头


DrawHeader(gfx, rectHeader);


_totalPageLines = Convert.ToInt32((printAreaHeight - rectFooter.Height - rectHeader.Height) / charHeight);


_currentPageLine = 0;


if(_stringToPrint == null)


_stringToPrint = GetNextLine();


while((_currentPageLine <= _totalPageLines) && (_stringToPrint != null))






{


float yPos = rectHeader.Bottom + (_currentPageLine * charHeight);


// Calculate printing rectangle area


RectangleF rectTextLine = new RectangleF(marginLeft, yPos, printAreaWidth, charHeight);


_stringToPrint = DrawTextLine(gfx, _stringToPrint, rectTextLine);


PutNextLine(_stringToPrint);


_currentPageLine++;


_currentLine++;


_stringToPrint = GetNextLine();


}


if(_printFooter)


DrawFooter(gfx, rectFooter);


_currentPageNumber++;


e.HasMorePages = HasMorePages();


}




#endregion






私有帮助器#region 私有帮助器






/**//// <summary>


/// 获取下一行的文本内容。


/// </summary>


/// <returns></returns>


private string GetNextLine()






{


string line = null;


if(_printMode == PrintTextMode.WrapText)






{


if(_buffer.Count == 0)


line = _sr.ReadLine();


else






{


line = (string) _buffer[0];


_buffer.RemoveAt(0);


}


}


else






{


if(_emptyBuffer)






{


if(_currentPageLine < _buffer.Count)






{


line = (string) _buffer[_currentPageLine];


_buffer[_currentPageLine] = null;


}


else






{


if(!HasBufferChars())






{


_buffer.Clear();


_emptyBuffer = false;


}


}


}


else






{


if(_currentPageLine <= _totalPageLines)


line = _sr.ReadLine();


_emptyBuffer = HasBufferChars();




if(line == null)


_emptyBuffer = HasBufferChars();


}


}


return line;


}






/**//// <summary>


/// 将处理过程推进到下一行。


/// </summary>


/// <param name="line"></param>


private void PutNextLine(string line)






{


if(_printMode == PrintTextMode.WrapText)






{


if(line.Length > 0)






{


if(_buffer.Count == 0)


_buffer.Add(line);


else


_buffer[0] = line;


}


}


else if(_printMode == PrintTextMode.BannerLike)






{


if(_currentPageLine < _buffer.Count)


_buffer[_currentPageLine] = line;


else


_buffer.Add(line);


}


}




private bool HasMorePages()






{


int moreChars = -1;


try






{


moreChars = _sr.Peek();


}


catch(Exception)






{}


return (moreChars != -1) || _emptyBuffer;


}




private bool HasBufferChars()






{


foreach(string str in _buffer)






{


if(str.Length > 0)


return true;


}


return false;


}




private string DrawTextLine(Graphics gfx, string text, RectangleF rectangle)






{


StringFormat fmt = new StringFormat();




if(_printLineNumbers)






{


Font fnLine = new Font(FontFamily.GenericMonospace, _printfont.Size);


string lineStr = String.Format("{0,4:G}", _currentLine);


SizeF szfLine = gfx.MeasureString(lineStr, fnLine, rectangle.Size, fmt);


gfx.DrawString(lineStr, fnLine, Brushes.Black, rectangle, fmt);


rectangle.Inflate(-(szfLine.Width + _printfont.Size), 0);


}


int charactersOnLine = GetLineBreakCharPosition(gfx, text, rectangle);


gfx.DrawString(text, _printfont, Brushes.Black, rectangle, fmt);


return text.Substring(charactersOnLine);


}




private int GetLineBreakCharPosition(Graphics gfx, string text, RectangleF rectangle)






{


StringFormat fmt = new StringFormat(StringFormatFlags.MeasureTrailingSpaces);




int charactersOnLine = 0;


int lines = 0;


SizeF sizeText = gfx.MeasureString(text, _printfont, rectangle.Size, fmt, out charactersOnLine, out lines);


string rem = text.Substring(0, charactersOnLine);


if(rem.EndsWith(" ") && (charactersOnLine < text.Length))






{




string noSpaces = rem.TrimEnd(new Char[]

{' '});


int nSpaces = rem.Length - noSpaces.Length;


SizeF sizeChunk =


gfx.MeasureString(noSpaces, _printfont, rectangle.Size, fmt, out charactersOnLine, out lines);


string spacer = String.Empty;


while(sizeChunk.Width <= rectangle.Width)






{


spacer += " ";


sizeChunk = gfx.MeasureString(noSpaces + spacer, _printfont, new PointF(0, 0), fmt);


}




charactersOnLine += spacer.Length - ((sizeChunk.Width > rectangle.Width) ? 1 : 0);


}




return charactersOnLine;


}






/**//// <summary>


/// 打印页眉。


/// </summary>


/// <param name="gfx"></param>


/// <param name="rectangle"></param>


private void DrawHeader(Graphics gfx, RectangleF rectangle)






{


StringFormat fmtHeader = new StringFormat();


string header = MakeHeaderFooterString(Header, ref fmtHeader);


gfx.DrawString(header, _headerFooterFont, Brushes.Black, rectangle, fmtHeader);


float yPos = rectangle.Top + (_headerFooterFont.GetHeight(gfx) + 2);


if(yPos <= rectangle.Bottom)


gfx.DrawLine(_penHeaderFooterLine, rectangle.Left, yPos, rectangle.Right, yPos);


}






/**//// <summary>


/// 打印页脚。


/// </summary>


/// <param name="gfx"></param>


/// <param name="rectangle"></param>


private void DrawFooter(Graphics gfx, RectangleF rectangle)






{


StringFormat fmtHeader = new StringFormat();


string header = MakeHeaderFooterString(Footer, ref fmtHeader);


fmtHeader.LineAlignment |= StringAlignment.Far;


gfx.DrawString(header, _headerFooterFont, Brushes.Black, rectangle, fmtHeader);


float yPos = rectangle.Bottom - (_headerFooterFont.GetHeight(gfx) + 2);


if(yPos >= rectangle.Top)


gfx.DrawLine(_penHeaderFooterLine, rectangle.Left, yPos, rectangle.Right, yPos);


}




private string MakeHeaderFooterString(string template, ref StringFormat format)






{


string headerFooter = template;


int ix = headerFooter.IndexOf("&l");


if(ix != -1)






{


format.Alignment = StringAlignment.Near;


headerFooter = headerFooter.Remove(ix, 2);


}




ix = headerFooter.IndexOf("&r");


if(ix != -1)






{


format.Alignment = StringAlignment.Far;


headerFooter = headerFooter.Remove(ix, 2);


}




ix = headerFooter.IndexOf("&c");


if(ix != -1)






{


format.Alignment = StringAlignment.Center;


headerFooter = headerFooter.Remove(ix, 2);


}


headerFooter = headerFooter.Replace("&p", (_currentPageNumber + 1).ToString());


headerFooter = headerFooter.Replace("&n", DocumentName);


DateTime dt = DateTime.Now;


ix = 0;


while((ix = headerFooter.IndexOf("%")) != -1)






{


bool found = false;


for(int i = 0; i < _dateFormat.Length; i++)






{


string fmt = "%" + _dateFormat[i];


if(headerFooter.Substring(ix, fmt.Length) == fmt)






{


string date = dt.ToString(_dateFormat[i], DateTimeFormatInfo.InvariantInfo);




headerFooter = headerFooter.Remove(ix, fmt.Length);


headerFooter = headerFooter.Insert(ix, date);


found = true;


break;


}


}


if(!found)


headerFooter = headerFooter.Remove(ix, 1);


}


return headerFooter;


}




#endregion






IDisposable 成员#region IDisposable 成员






/**//// <summary>


/// 移除由 <b>TextPrintDocument</b> 使用的所有托管资源。


/// </summary>


public new void Dispose()






{


Dispose(true);


}






/**//// <summary>


///


/// </summary>


/// <param name="disposing"></param>


protected override void Dispose(bool disposing)






{


if(disposing)






{


lock(this)






{


if (_sr != null)


_sr.Dispose();


}


GC.SuppressFinalize(true);


}


base.Dispose(disposing);


}






/**//// <summary>


/// 供 <see cref="GC"/> 使用的清理托管资源的方法。


/// </summary>


~TextPrintDocument()






{


Dispose(false);


}




#endregion


}






/**//// <summary>


/// 指定打印文本的模式。


/// </summary>


internal enum PrintTextMode






{




/**//// <summary>


/// 换行文本。


/// </summary>


WrapText,


Truncate,


BannerLike


}


}