1000只瓶中有一瓶毒药_瓶中的信息

灰太狼 2022-12-06 15:38 167阅读 0赞

1000只瓶中有一瓶毒药

Delphi, you've got message to handle!

Delphi，您有消息要处理！

One of the keys to traditional Windows programming is handling the **messages** sent by Windows to applications. Simply put, a message is some information sent from one place to another. For the most part, Delphi makes message handling easy through its use of events, an event is usually generated in response to a Windows message being sent to an application.

传统Windows编程的关键之一是处理Windows发送给应用程序的**消息** 。 简而言之，消息是从一个地方发送到另一个地方的一些信息。 在大多数情况下，Delphi通过使用事件使消息处理变得容易，事件通常是响应Windows消息发送到应用程序而生成的。

However, someday you may want to process some uncommon messages like: CM\_MOUSEENTER which happens (is posted by Windows) when [mouse][] cursor enters the client area of some component (or form).

但是，有一天，您可能希望处理一些不常见的消息，例如：CM\_MOUSEENTER，当[鼠标][mouse]光标进入某个组件(或窗体)的客户区域时会发生(由Windows发布)。

Handling messages on their own requires a few extra programming techniques, this article is here to help us find the right way through the message river and grap needed information.

自行处理消息需要一些额外的编程技术，本文旨在帮助我们找到通过消息河的正确方法并掌握所需的信息。

## 使用Delphi处理Windows消息的策略 **(** Strategies to Manipulate Windows Messages With Delphi **)** ##

*  [Drag a Window][]: No title bar! How can you drag such a window? It's easy and fun: let's make a Delphi form move by clicking (and dragging) in it's client area. The main idea is to get your hands on the wm\_NCHitTest windows message.
    
    [拖动窗口][Drag a Window] ：无标题栏！ 您如何拖动这样的窗口？ 它既简单又有趣：让我们通过单击(并拖动)其客户区域来移动Delphi表单。 主要思想是让您掌握wm\_NCHitTest Windows消息。
 *  [How to send information (String, Image, Record) between two Delphi applications (WM\_CopyData)][How to send information _String_ Image_ Record_ between two Delphi applications _WM_CopyData]: Learn how to send the WM\_CopyData message between two Delphi applications to exchange information and make two applications communicate. The accompanying source code demonstrates how to send a string, record (complex data type) and even graphics to another application.
    
    [如何在两个Delphi应用程序(WM\_CopyData)之间发送信息(字符串，图像，记录)][How to send information _String_ Image_ Record_ between two Delphi applications _WM_CopyData] ：了解如何在两个Delphi应用程序之间发送WM\_CopyData消息以交换信息并使两个应用程序通信。 随附的源代码演示了如何向另一个应用程序发送字符串，记录(复杂数据类型)甚至图形。
 *  Sticky Windows: This strategy allows you to dock your Delphi forms to the edges of your desktop screen.
    
    粘性Windows：此策略可让您将Delphi表单停靠在桌面屏幕的边缘。
 *  [Monitoring Registry Changes][]: Need to get notified about changes to the attributes or contents of a specified Registry key? Then you are ready for this your Delphi code toolkit.
    
    [监视注册表更改][Monitoring Registry Changes] ：是否需要通知有关指定注册表项的属性或内容的更改？ 然后，您就可以为此使用Delphi代码工具包了。
 *  Sending Messages to Non-Windowed Applications: This strategy is used to send messages (signals) to non-windowed applications by using AllocateHWND and DefWindowProc. You should understand what Delphi does in the background to intercept Windows messages, how can you write your own message handler for a windowed application and how to obtain a unique message identifier that you can safely use in your applications. There is also a small bug in the Delphi DeallocateHWND procedure that you can fix along the way.
    
    将消息发送到非窗口应用程序：此策略用于通过使用AllocateHWND和DefWindowProc将消息(信号)发送到非窗口应用程序。 您应该了解Delphi在后台如何截获Windows消息，如何为窗口化应用程序编写自己的消息处理程序以及如何获取可以在应用程序中安全使用的唯一消息标识符。 Delphi DeallocateHWND过程中还有一个小错误，您可以一路修复。
 *  [Controlling the Number of Application Instances][]: In this article you'll learn how to "run-once enable" a Delphi application that can check for its previous (running) instance. Along the process, several techniques of implementing such a check will be discussed; as well as how to bring your already running application to the foreground, if a user tries to run it "one more time". By the end of the article you'll have a copy-to-go code to control the behavior of your application's multiple instances: with the option to limit the number of running instances.
    
    [控制应用程序实例的数量][Controlling the Number of Application Instances] ：在本文中，您将学习如何“一次运行”一个Delphi应用程序，该应用程序可以检查其先前(正在运行的)实例。 在此过程中，将讨论实现这种检查的几种技术。 以及如果用户尝试“再运行一次”，如何将已经运行的应用程序置于前台。 到本文结尾，您将拥有一个复制到代码，以控制应用程序的多个实例的行为：可以选择限制正在运行的实例的数量。
 *  [How to Handle System Time Change Using Delphi Code][]: If you need to react when system date time has changed you can handle the WM\_TimeChange Windows message.
    
    [如何使用Delphi代码处理系统时间更改][How to Handle System Time Change Using Delphi Code] ：如果您需要在系统日期时间更改后做出React，则可以处理WM\_TimeChange Windows消息。
 *  How to Draw Custom Text on a Delphi Form's Caption Bar: If you want to add some custom text on the caption bar of a form, without changing the Caption property of the form you need to handle one special Windows message: WM\_NCPAINT (along with WM\_NCACTIVATE).
    
    如何在Delphi窗体的标题栏上绘制自定义文本：如果要在窗体的标题栏上添加一些自定义文本，而无需更改窗体的Caption属性，则需要处理一条特殊的Windows消息：WM\_NCPAINT(以及WM\_NCACTIVATE )。
 *  [How to Display Menu Item Hints][]: By (Windows) design, in Delphi applications, hints assigned to menu items do not get displayed in the popup tooltip window (when the mouse hovers over a menu).
    
    [如何显示菜单项提示][How to Display Menu Item Hints] ：通过(Windows)设计，在Delphi应用程序中，分配给菜单项的提示不会在弹出的工具提示窗口中显示(当鼠标悬停在菜单上时)。
 *  Get, Set, and Handle Display Device Modes (Screen Resolution and Color Depth): This strategy allows you to change the Windows display mode settings (resolution and color depth) from Delphi code. You can also handle the WM\_DISPLAYCHANGE Windows message sent to all windows when the display resolution has changed.
    
    获取，设置和处理显示设备模式(屏幕分辨率和颜色深度)：此策略使您可以从Delphi代码更改Windows显示模式设置(分辨率和颜色深度)。 当显示分辨率更改时，您也可以处理发送到所有窗口的WM\_DISPLAYCHANGE Windows消息。
 *  Get Current URL From IE: There is a Delphi tactic to retrieve the full URL of all opened Internet Explorer instances.
    
    从IE获取当前URL：有一种Delphi策略可检索所有打开的Internet Explorer实例的完整URL。
 *  Detecting and Preventing Windows Shut Down: You can use Delphi to programmatically cancel Windows shut down action.
    
    检测和防止Windows关闭：您可以使用Delphi以编程方式取消Windows关闭操作。
 *  [Display a Password Dialog:][Display a Password Dialog] Suppose you have a data-critical type of application where you would not want a non-authored user to work with the data. What if you need to display a password dialog \*before\* the application is restored to make sure an authorized user is accessing it.
    
    [显示密码对话框：][Display a Password Dialog]假设您有一个数据关键型应用程序，您不希望非授权用户使用该数据。 如果需要在还原应用程序之前\*之前显示密码对话框，以确保授权用户能够访问它，该怎么办。
 *  Remove the Windows Constraint on Minimum Form Size: By Windows design, a form (window) has a size constraint that sets the minimum form height to the height of the caption bar and the width to 112 pixels (118 in XP theme).
    
    删除Windows对最小表单大小的约束：通过Windows设计，表单(窗口)具有大小约束，该约束将最小表单高度设置为标题栏的高度，并将宽度设置为112像素(XP主题中为118)。
 *  How to Detect a TPopupMenu's OnClose (OnPopDown) Event: Unfortunately, the TPopupMenu does not expose an event you can handle that will fire when the menu gets closed - either after a user has selected an item from the menu or has activated some other UI element.
    
    如何检测TPopupMenu的OnClose(OnPopDown)事件：不幸的是，TPopupMenu没有公开您可以处理的事件，该事件将在菜单关闭时触发-在用户从菜单中选择一个项目或激活了其他UI元素之后。
 *  [Trapping Messages Sent to an Application][]: "...Delphi surfaces the OnMessage event for the Application object. The OnMessage event handler is "supposed" to allow you trap every message sent to your application..."
    
    [捕获发送到应用程序的消息][Trapping Messages Sent to an Application] ：“ ... Delphi公开了Application对象的OnMessage事件。”应该“设置OnMessage事件处理程序，以允许您捕获发送到应用程序的每条消息...”

> 翻译自: [https://www.thoughtco.com/message-in-the-bottle-1058444][https_www.thoughtco.com_message-in-the-bottle-1058444]

1000只瓶中有一瓶毒药

[mouse]: https://www.thoughtco.com/advanced-mouse-processing-1058399
[Drag a Window]: https://www.thoughtco.com/drag-a-delphi-form-1058461
[How to send information _String_ Image_ Record_ between two Delphi applications _WM_CopyData]: https://www.thoughtco.com/send-information-between-applications-1058476
[Monitoring Registry Changes]: https://www.thoughtco.com/working-with-windows-registry-1058474
[Controlling the Number of Application Instances]: https://www.thoughtco.com/understanding-delphi-project-files-dpr-1057652
[How to Handle System Time Change Using Delphi Code]: https://www.thoughtco.com/display-a-topmost-system-modal-message-1058468
[How to Display Menu Item Hints]: https://www.thoughtco.com/how-to-display-menu-item-hints-1058397
[Display a Password Dialog]: https://www.thoughtco.com/display-a-login-password-dialog-1058469
[Trapping Messages Sent to an Application]: http://www.delphicorner.f9.co.uk/articles/apps7.htm
[https_www.thoughtco.com_message-in-the-bottle-1058444]: https://www.thoughtco.com/message-in-the-bottle-1058444