精通.NET中的日常打印（使用C# 非常实用）

文章标题是翻译出的中文标题，英文原文标题为：Master Everyday Printing in .NET

文章来自Fawcette Technical Publications(www.ftponline.com)

文章详细地讲述了 System.Drawing.Printing 命名空间中的 20个类 7 个枚举以及 3个委托的用法。

本文将先贴出英文原文，最后再贴出完整源代码，希望对大家有所帮助！

英文原文：

Listing 1 C#

Create and Dispose.

The PrintDocument object exposes several events. BeginPrint is fired before any pages are actually printed, giving you the opportunity to allocate objects or open files. EndPrint occurs after the last page has been printed. Don’t forget to bind the events to your PrintDocument object.

// At the class level

private Font bodyFont;

private Font headerFont;

private StreamReader data;

private PrintDocument doc;

private void MainForm_Load(object

sender, System.EventArgs e) {

doc = new PrintDocument();

// shows up in Print Manager

doc.DocumentName = “Contact List”;

doc.BeginPrint += new

PrintEventHandler(doc_BeginPrint);

doc.EndPrint += new

PrintEventHandler(doc_EndPrint);

}

private void doc_BeginPrint(object

sender, PrintEventArgs pv) {

data = new

StreamReader("contacts.csv");

Font bodyFont = new Font(“Arial”,

12);

Font headerFont = new Font(“Arial”,

24);

}

private void doc_EndPrint(object

sender, PrintEventArgs pv) {

data.Close();

bodyFont.Dispose();

headerFont.Dispose();

}

Listing 2 C#

Inherit From PrintDocument.

Derive a new class from PrintDocument so you can encapsulate all your printing functionality in a single place, enhancing code reuse.

public class CustomPrintDocument : PrintDocument {

private StreamReader dataToPrint;

public CustomPrintDocument(StreamReader data) : base()

{

dataToPrint = data;

}

protected override void OnBeginPrint(PrintEventArgs

ev) {

base.OnBeginPrint(ev) ;

}

protected override void OnEndPrint(PrintEventArgs ev)

{

base.OnEndPrint(ev);

}

protected override void

OnQueryPageSettings(QueryPageSettingsEventArgs ev)

{

base.OnQueryPageSettings(ev);

}

protected override void OnPrintPage(PrintPageEventArgs

ev) {

base.OnPrintPage(ev);

ev.Graphics.DrawString("this is a test", new

Font("Arial", 24), Brushes.Black, 100, 100);

ev.HasMorePages = false;

}

Listing 3 C#

Retrieve the Margins With P/Invoke.

The .NET Framework doesn’t provide a way to retrieve the hard margins of a printer, so you need to use P/Invoke and call the Win32 GetDeviceCaps function. The method in this class takes a device handle (hDc), then populates the class members with the information you need.

[DllImport("gdi32.dll")]

private static extern Int16 GetDeviceCaps([In] [MarshalAs

(UnmanagedType.U4)] int hDc, [In] [MarshalAs

(UnmanagedType.U2)] Int16 funct);

private float _leftMargin = 0;

private float _topMargin = 0;

private float _rightMargin = 0;

private float _bottomMargin = 0;

const short HORZSIZE = 4;

const short VERTSIZE = 6;

const short HORZRES = 8;

const short VERTRES = 10;

const short PHYSICALOFFSETX = 112;

const short PHYSICALOFFSETY = 113;

public marginInfo(int deviceHandle) {

float offx = Convert.ToSingle(

GetDeviceCaps(deviceHandle, PHYSICALOFFSETX));

float offy = Convert.ToSingle(

GetDeviceCaps(deviceHandle, PHYSICALOFFSETY));

float resx = Convert.ToSingle(

GetDeviceCaps(deviceHandle, HORZRES));

float resy = Convert.ToSingle(

GetDeviceCaps(deviceHandle, VERTRES));

float hsz = Convert.ToSingle(

GetDeviceCaps(deviceHandle, HORZSIZE))/25.4f;

float vsz = Convert.ToSingle(

GetDeviceCaps(deviceHandle,VERTSIZE))/25.4f;

float ppix = resx/hsz;

float ppiy = resy/vsz;

_leftMargin = (offx/ppix) * 100.0f;

_topMargin = (offy/ppix) * 100.0f;

_bottomMargin = _topMargin + (vsz * 100.0f);

_rightMargin = _leftMargin + (hsz * 100.0f);

}

Listing 4 C#

Lay Out the Report.

The basic format of any report must include at least a header, body, and footer section. Use Rectangle objects to lay out your reports easily. You can increase the complexity of those reports by adding more Rectangle objects.

// create the header

int headerHeight =

hf.GetHeight(ev.Graphics);

RectangleF header = new

RectangleF(leftMargin, topMargin,

pageWidth, headerHeight);

// create the footer

int bodyFontHeight =

bodyFont.GetHeight(ev.Graphics);

RectangleF footer = new

RectangleF(leftMargin, body.Bottom,

pageWidth, bodyFontHeight);

// create the body section

RectangleF body = new

RectangleF(leftMargin, header.Bottom,

pageWidth, pageHeight –

bodyFontHeight);

Listing 5 C#

PrintPage Provides the Key to Printing.

The PrintPage event is the primary event you’ll use when printing using the System.Drawing.Printing objects. This event fires once per page until you set the value of ev.HasMorePages to false. The code used to retrieve the hard margins makes up for any shortcomings in the .NET Framework.

private void doc_PrintPage(object sender,

System.Drawing.Printing.PrintPageEventArgs ev) {

_currentPage++;

String headerText = "Northwinds Customer Contacts";

IntPtr hDc = ev.Graphics.GetHdc();

ev.Graphics.ReleaseHdc(hDc);

marginInfo mi = new marginInfo(hDc.ToInt32());

// take the hard margins into account…

float leftMargin = ev.MarginBounds.Left - mi.Left;

float rightMargin = ev.MarginBounds.Right;

float topMargin = ev.MarginBounds.Top - mi.Left;

float bottomMargin = ev.MarginBounds.Bottom;

float pageHeight = bottomMargin - topMargin;

float pageWidth = rightMargin - leftMargin;

float headerHeight =

headerFont.GetHeight(ev.Graphics);

float footerHeight = bodyFont.GetHeight(ev.Graphics);

// report header

RectangleF ReportheaderR = new RectangleF(leftMargin,

topMargin, pageWidth, headerHeight);

// report body

RectangleF bodyR = new RectangleF(leftMargin,

ReportheaderR.Bottom, pageWidth, pageHeight –

ReportheaderR.Height - footerHeight);

// report footer

RectangleF ReportfooterR = new RectangleF(leftMargin,

bodyR.Bottom, pageWidth, footerHeight * 2);

// results of using the Split function on the text

String[] el;

// a line of text from our file

string text = "";

// print the header once per page

centerText(ev.Graphics, headerText, headerFont,

defaultBrush, ReportheaderR);

// the header is equal to 2 normal lines

int currentLine = 2;

// how many lines can we fit on a page?

int linesPerPage = Convert.ToInt32(bodyR.Height /

bodyFont.GetHeight(ev.Graphics)) - 1;

float bodyFontHeight =

bodyFont.GetHeight(ev.Graphics);

float currentY;

// Print each line of the file.

while(currentLine < linesPerPage &&

((text=data.ReadLine()) != null)) {

el = text.Split(',');