从Delphi打印不同的文档类型

比眉伴天荒 2022-12-06 15:45 185阅读 0赞

If your [Delphi][] application needs to operate on various types of files, one of the tasks you might have for your application is to allow the user of the application to print a file, whatever the file type is.

如果您的[Delphi][]应用程序需要处理各种类型的文件，则对于应用程序，您可能要执行的任务之一是允许应用程序的用户打印文件，无论文件类型是什么。

Most document-oriented applications, like MS Word, MS Excel or Adobe can easily print documents created in that program. For example, [Microsoft][] Word saves the text you write in documents with DOC extension. Since Word determines what is the "raw" contents of a .DOC file it knows how to print .DOC files. The same applies for any "known" file type holding some printable information.

大多数面向文档的应用程序，例如MS Word，MS Excel或Adobe，都可以轻松打印在该程序中创建的文档。 例如， [Microsoft][] Word将您编写的文本保存在带有DOC扩展名的文档中。 由于Word确定.DOC文件的“原始”内容是什么，因此它知道如何打印.DOC文件。 持有某些可打印信息的任何“已知”文件类型也是如此。

What if you need to print various types of documents/files from your application? Can you know how to send the file to the printer in order for it to be printed correctly?

如果您需要从应用程序中打印各种类型的文档/文件怎么办？ 您知道如何将文件发送到打印机以使其正确打印吗？

## 从Delphi打印 **(** Print From Delphi **)** ##

We can ask Windows what application can print, for example, a PDF file. Or, even better, we can tell Windows, here's one PDF file, send it to the application associated / in charge of printing PDF files.

我们可以询问Windows可以打印哪些应用程序，例如PDF文件。 或者，甚至更好的是，我们可以告诉Windows，这是一个PDF文件，将其发送到关联的/负责打印PDF文件的应用程序。

To do this, open up Windows Explorer, navigate to a directory containing some printable files. For most of the file types on your system, when you right-click a file in Windows Explorer, you will locate the "Print" command. Executing the Print shell command will result in the file being sent to the default printer. Well, that's exactly what we want: for a file type, call a method that will send the file to the associated application for printing. The function we are after is the ShellExecute API function.

为此，请打开Windows资源管理器，导航到包含一些可打印文件的目录。 对于系统上的大多数文件类型，在Windows资源管理器中右键单击文件时，将找到“打印”命令。 执行“打印shell”命令将导致文件发送到默认打印机。 好吧，这正是我们想要的：对于文件类型，调用将文件发送到关联的应用程序进行打印的方法。 我们需要的函数是ShellExecute API函数。

## ShellExecute：打印/打印到 **(** ShellExecute: Print / PrintTo **)** ##

However, ShellExecute can do much more. ShellExecute can be used to [launch an application][], open Windows Explorer, initiate a search beginning in the specified directory, and—what's of greatest interest to us—print the specified file.

但是，ShellExecute可以做更多的事情。 ShellExecute可用于[启动应用程序][launch an application] ，打开Windows资源管理器，从指定目录开始的搜索，以及-对我们最大的兴趣-打印指定的文件。

## 指定打印机 **(** Specify Printer **)** ##

Using the above call, a document "document.doc" located on the root of the C drive will be sent to the Windows default printer. ShellExecute always uses the default printer for the "print" action. What if you need to print to a different printer, what if you want to allow the user to change the printer?

使用上述调用，位于C驱动器根目录下的文档“ document.doc”将被发送到Windows默认打印机。 ShellExecute始终将默认打印机用于“打印”操作。 如果需要打印到其他打印机该怎么办，如果要允许用户更换打印机该怎么办？

## PrintTo Shell命令 **(** The PrintTo Shell Command **)** ##

Before you copy and paste: the Printer global variable (TPrinter type) available in all Delphi programs can be used to manage any printing performed by an application. The printer is defined in the "printers" unit, ShellExecute is defined in the "shellapi" unit.

复制和粘贴之前：所有Delphi程序中可用的Printer全局变量(TPrinter类型)可用于管理应用程序执行的任何打印。 打印机在“打印机”单元中定义，ShellExecute在“ shellapi”单元中定义。

1.  Drop a TComboBox on a form. Name it "cboPrinter". Set Style to csDropDownLidt
    
    将TComboBox放到窗体上。 将其命名为“ cboPrinter”。 将样式设置为csDropDownLidt
2.  Put the next two lines in the form's OnCreate even handler:
    
    将接下来的两行放在表单的OnCreate偶数处理程序中：
    
        //have available printers in the combo boxcboPrinter.Items.Assign(printer.Printers);//pre-select the default / active printercboPrinter.ItemIndex := printer.PrinterIndex;

use to print any document type to a specified printer

*Note: some document types do not have an application associated with printing. Some do not have the "printto" action specified.*

*注意：某些文档类型没有与打印相关的应用程序。* *有些没有指定“ printto”操作。*

> 翻译自: [https://www.thoughtco.com/print-documents-from-delphi-1057936][https_www.thoughtco.com_print-documents-from-delphi-1057936]

[Delphi]: https://www.thoughtco.com/beginners-guide-to-delphi-enter-topic-1057658
[Microsoft]: https://www.thoughtco.com/microsoft-history-of-a-computing-giant-1991140
[launch an application]: https://www.thoughtco.com/execute-and-run-applications-1058462
[https_www.thoughtco.com_print-documents-from-delphi-1057936]: https://www.thoughtco.com/print-documents-from-delphi-1057936