Interface design and test specifications

There are three styles of popular interface styles, multiple forms, single forms, and explorer style , regardless of the style, the following rules should be valued.
1, ease of Use: The button name should be easy to understand, with accurate words, screen discard not ambiguous words, to the same interface with the other buttons easy to distinguish, can hope the text to know the best. Ideally, users will be able to know the functionality of the interface and perform the correct operation without consulting the help.
Ease of Use details:
1), complete the same or similar functions of the button with frame frame up, commonly used buttons to support shortcuts.
2), the element that completes the same function or task is placed in the centralized position, reduces the mouse movement distance.
3), according to the function of the interface divided into local blocks, framed by frame, and to have functional description or title.
4), the interface to support the keyboard automatic navigation button function, that is, press the TAB key automatic switching function.
5), the interface on the first input and important information of the control in the tab order should be in the front, position should also be placed on the window more prominent position.
6), the number of controls on the same interface should not be more than 10, more than 10 can consider using the paging interface display.
7), paging interface to support the quick switch between pages, commonly used combination shortcut keys Ctrl+tab
8), default button to support enter and select operation, that is, press ENTER to automatically perform the default button corresponding action.
9), the writable control detects the illegal input should give a description and can automatically get the focus.
10), the Order of the TAB key and the order of the control to always, the current prevalence of the overall from the top to the bottom, while the lines from left to right way.
11), check boxes and Options boxes are ranked by the high bottom of the selection odds.
12), check boxes and Options boxes have default options and Support tab selection.
13), with the same number of options, use the option box instead of the drop-down list box.
14), use the drop-down box instead of the option box when the interface space is small.
15), the number of options is called when you use the options box instead of the drop-down list box.
16), professional software to use the relevant professional terminology, universal interface advocates the use of universal word eye.

2, normative: The interface design is usually in accordance with the specifications of the Windows interface design, that is, "menu, toolbar, tool compartment, status bar, scroll bar, right-click shortcut menu," The standard format, you can say, the interface to follow the higher degree of normalization, the use of the corresponding better. Small software generally does not provide a tool compartment.
Normative rules:
1), common menu to have a command shortcut.
2), complete the same or similar functions of the menu is separated by horizontal line in the same position.
3), the icon in front of the menu can visually represent the operation to be done.
4), the menu depth is generally required to control up to three levels.
5), toolbar requirements can be customized according to the requirements of the user's own choice.
6), the same or similar functions of the toolbar put together.
7), each button in the toolbar to have prompt information.
8), the maximum length of a toolbar cannot exceed the screen width.
9), the toolbar icon can be a visual representation of the operation to be done.
10), the System common toolbar sets the default placement location.
11), tool bar too much to consider using the tool compartment.
12), the tool compartment to be able to increase or decrease, by the user's own customized according to demand.
13), the default total width of the tool compartment should not exceed 1/5 of the screen width.
14), the status bar to be able to display the user's actual needs of information, commonly used,
The current operation, system status, user location, user information, prompt information, error messages, and so on, if an operation takes a long time, you should also display the progress bar and process tips.
15), the length of the scroll bar according to the length or width of the display information can be changed in time to facilitate the user to understand the location and percentage of information displayed.
16), the height of the status bar to place five good words, the width of the scroll bar is slightly narrower than the state bar.
17), menu and tool bar to have a clear boundary, menu requirements protruding display, so that when the toolbar to remove the three-dimensional.
18), the menu and the status bar usually use the number 5th font. The tool bar is generally wider than the menu, but not too wide, otherwise it looks very uncoordinated.
19), the right-click shortcut menu uses the same guidelines as the menu.

3, Help facilities: The system should provide detailed and reliable help documents, in the user's use to create confusion, you can find a solution.

Help facility details.
1), the performance introduction and description in the Help document to match the system performance. (Our system Help documentation is a description of the system's ancestral period, confusing).
2), when packaging the new system, the modification of the place in the Help document to make the corresponding changes.
3), the operation to provide timely call system help function. Commonly used F1.
4), when you invoke Help on the interface, you should be able to locate the help location relative to the operation in a timely manner. That is to say, help should be targeted immediately.
5), it is best to provide the current popular online Help format or HTML Help format.
6), users can use keywords in the Help Index to search for help, of course, should also provide help the main inscription.
7), if you do not provide a written help document, it is best to have the function of printing help.
8), in the help should provide our technical support, once the user is difficult to solve their own can easily find new ways to help.

4, Rationality: the screen diagonal intersection position is the user to look directly at the place, just above One-fourth is easy to attract the user attention position, should pay attention to take advantage of these two positions when placing the form.
Reasonable rules.
1), the center position of the parent form or main form should be near the diagonal focus.
2), the subform position should be in the upper-left or middle of the main form.
3), multiple sub-forms should be shifted to the right and bottom to show that the form is the appropriate title.
4), important command buttons and the use of more frequent buttons to be placed on the interface to the attention of the position.
5), the wrong use of the interface can easily cause the exit or close button should not be placed in the easy position. The horizontal start or the last with the vertical row is the easy point position.
6), buttons unrelated to the in-progress operation should be masked (grayed out in Windows, this button is not available).
7), for operations that may cause data to be unrecoverable, must provide confirmation information, giving the user the opportunity to opt out.
8), illegal input or operation should have enough prompt explanation.
9), to the operation of the problem occurred in the place to cause errors to be prompted, so that users understand the wrong source, to avoid the formation of indefinite waiting.
10), hints, warnings, or error descriptions should be clear, clear and appropriate.

5, aesthetics and coordination: the interface should be sized to suit the aesthetic point of view, the feeling of coordination and comfort, in an effective range to attract the attention of users.

aesthetics and coordination of the rules.
1),   long and wide close to the golden point ratio, avoid the length of the imbalance, or width over length.
2),   layout should be reasonable, not too dense, nor too empty, reasonable use of space.
3),   button size basically similar, avoid using too long name, lest occupy excessive interface position.
4), the size of the   button to coordinate with the size and space of the interface.
5)   Avoid placing large buttons on the empty interface.
6),   the interface should not have a large vacant position after the control has been placed.
7),   the size of the font to be proportional to the size of the interface,  commonly used fonts in Arial 9-12 are more beautiful, rarely use more than 12th font.
8),   foreground and background color collocation reasonable coordination, contrast should not be too big, preferably less dark, such as red, Big green and so on. Common colors Consider using the Windows interface tones.
9),   if the use of other colors, the main color to be soft, with affinity and magnetism, resolutely eliminate the color of the thorn.
10),   large systems commonly used in the main color has "#E1E1E1", "#EFEFEF", "#C0C0C0" and so on.
11),   interface style to be consistent, the size of the word, color, font to be the same, unless it is necessary for artistic processing or special requirements of the place.
12),   if the form supports minimizing and maximizing or zooming in, the controls on the form will also be scaled with the form; Do not enlarge the form only to ignore the control's scaling.
13), for the interface containing the button should not generally support scaling, that is, the upper-right corner only the shutdown function.
14),   The subform does not necessarily scale when the parent form supports zooming.
15), if you can provide users with custom interface style is better, by the user to choose their own color, font and so on.

6, Menu Location: Menu is the most important element of the interface, the menu location according to function to organize.
Menu Set Test Details:
1), menus are usually arranged in a "common--primary--minor--tool-Help" location, in line with the popular Windows style.
2), commonly used have "file", "edit", "View" and so on, almost every system has these options, of course, according to different systems have a choice.
3), drop-down menu to be based on the meaning of the menu options to group, and cut according to a certain rules of the arrangement, separated by a horizontal line.
4), the use of a set of menus have a succession of requirements or a guide, should be ranked in order.
5), there is no order of the menu items according to the use of frequency and importance of the arrangement, commonly used in the beginning, not commonly used to put on the back, important in the beginning, the secondary is placed behind.
6), if there are more menu options, the length of the extended menu should be used to reduce the depth of the principle of arrangement.
7), the menu depth is generally required to control up to three levels.
8), the common menu to have a quick command, the combination of principles see 8.
9), the menu that is unrelated to the operation to be handled in a shielded way, if the use of dynamic loading mode-that is, only the required menu is displayed-the best.
10), the icon in front of the menu should not be too large, and the word height to keep the best.
11), the main menu width to close, the number of words should not be more than four, each menu can be the same number of words the best.
12), the number of main menu should not be too much, preferably a single row layout.

7, Uniqueness: If blindly follow the industry's interface standards, will lose their own personality. It is particularly important to design an interface that has its own unique style when the framework conforms to the above specifications. Especially in the commercial software circulation has the very good migration the implicit advertisement utility.
1), installation interface should be introduced or product introduction, and has its own icon.
2), the main interface, it is best to have a company icon on most interfaces.
3), the login interface to have the product logo, including the company icon.
4), the "about" in the Help menu should have copyright and product information.
5), the company's series of products to maintain the interface style, such as background color, font, menu arrangement, icons, installation process, button language should be broadly consistent.

8, shortcut combination
Use shortcut keys in menus and buttons to make it faster for users who prefer to use the keyboard. The use of shortcut keys in western Windows and its applications is mostly consistent.
Menu,
1, transaction-oriented combinations are:
ctrl-d  delete  ;Ctrl-F  find  ;ctrl –h replace;ctrl-i  insert   ;ctrl-n  New record  ;Ctrl-S  save  Ctrl- O  Open.
2), list:
ctrl-r ,ctrl-g positioning; ctrl-tab next page window or reverse-order browse the same page control;.
3), edit,
ctrl-a Select all;ctrl-c  copy;ctrl-v  paste;ctrl-x  cut; ctrl-z undo operation; Ctrl-y restore operation.
4) file operation:
ctrl-p  print;ctrl-w  off.
5), System menu:
alt-a file; alt-e edit; alt-t tool; alt-w window; alt-h Help.
6), Ms windows hold key:
ctrl-esc  Task List  ;Ctrl-F4  close window; alt-f4  end app;alt-tab  Next app  ;Enter  default button/Confirm Action  ;Esc  Cancel button/Cancel Action  ;Shift-F1  context-sensitive help  .
Button:
can be adjusted according to the needs of the system, the following are only common combinations.
Alt-y OK (yes), alt-c cancel;alt-n  No, alt-d Delete, alt-q exit, alt-a Add, alt-e Edit, alt-b browse; alt-r read; Alt-w write.
These shortcuts can also be used as a standard for developing Chinese applications, but they may be preceded by the initials of Hanyu Pinyin.

9, security considerations:
in the interface by the following means to control the probability of error, will greatly reduce the system due to user-induced errors caused by the damage. Developers should take into account all possible problems and minimize the likelihood of errors. If the application has a protective error and exits the system, this error is most likely to cause the user to lose confidence in the software. Because this means that the user wants to break the train of thought, and time and effort to re-login, and the operation has been done because there is no disk and all lost.
Security Rules:
1), and most importantly, exclude errors that may cause the application to abort abnormally.
2), should be careful to avoid the user inadvertently input invalid data.
3), using related controls to restrict the types of user input values.　
4), you can use a single box when there are only two possibilities for the user to make a selection.
5), when the selection may be more, you can take a check box, each choice is valid, the user cannot enter any invalid choice.
6), you can use a list box, drop-down list box for a special long-term election.
7), in an application, the developer should avoid the user to make unauthorized or meaningless operation.
8), limit or block the input characters or actions that may cause fatal errors or system errors.
9), remedial action should be taken for operations that may have serious consequences. By remediation The user can return to the original correct state.
10), the input of some special symbols, characters that conflict with the symbols used by the system, and prevents the user from entering the character.
11), for error operations it is best to support reversible processing, such as canceling a series of operations.
12), you should prevent the user from doing an operation that is only entered after the validation character is entered.
13), the cancellation function should be provided for operations that may cause long wait times.
14), special character Fuchang;; ' " ><, "," ["{, \|}]+=)-(_*&&^%$#@!~,.。?/There are spaces.
15), which conflicts with the reserved characters used by the system, should be limited.
16), when reading the information entered by the user, choose whether or not to remove the front and back spaces as needed.
17), some fields read into the database does not support the middle of the space, but the user really need to enter the middle space, this time to be processed in the program.

10. Multi-window application and system resources
Well-designed software should not only have a complete function, but also to occupy the most limited resources as far as possible.
1), in a multi-window system, some interface requirements must be kept at the top level, to avoid the user when opening multiple windows, non-stop switching or even minimize other windows to display the window.
2), after loading the main interface, automatically unload the memory, let out the occupied Windows system resources.
3), close all forms, and release all system resources that are accounted for when the system exits, unless it is a system that needs to run in the background.
4), as far as possible to prevent the exclusive use of the system.

Iv. graphical user interface Design What is an excellent graphical user interface? After all, a word, a good user interface is an intuitive, user-transparent interface, the user in the first contact with the software after the feel at a glance, do not need much training can be easily used to get started. It's easy to say, but it's not easy to actually do that in real-world development. For Windows developers, Microsoft's published window interface, application Design Guide ("The Windows Interface, an application design Guides (1992)") is a recognized standard for interface design on a microcomputer platform. Despite the continuous advances in technology, new window controls are constantly appearing, resulting in many of these standards being added or modified. But in general, every programmer will recognize that some of the most basic standards should be followed in their programming, even though they are unfamiliar with some parts of the standard or are not used. This article will discuss such a number of programmers and users have been accepted by the user interface design principles and norms.

1. User requirements for programmers who have long been engaged in the mainframe structure and developed under the character interface, the biggest obstacle to entering the Windows client/server environment is to recognize that the user is the center of all software processing in the software being written, and that it should not be the application that determines the process. This idea corresponds to the event-driven programming approach in PowerBuilder. A good graphical user interface (hereinafter referred to as the GUI) should be used by the user to control how the application works and respond, rather than being imposed on the user by the programmer at his own will. When writing event drivers, you should specify a single, unique responder for each action or event. The source power that triggers these events and causes these responders to execute is not the application, but the user. For example, when I use modem dial-up Internet, when the line is turned on, the screen will appear the following message, prompting the user to enter the login information in the order specified, Annex Command line interpreter
*copyright (C) 1988,1995 xylogics,inc.
Checking authorization, please wait ...
Annex username, Sjhzyz
Annex Password,
Permission granted
Annex, PPP
Switching to PPP.
This is a typical character-based interface of the application software, the entire process of login is determined by the program, prompting the user to enter content. In contrast, the Internet in a box software provided by the ISP provides another user login window in an e-mail management item, which is a GUI-based application in which the user becomes the owner of the software process, and the user can determine the order in which the information is entered according to their wishes. , or you can modify the input content until you click the OK button to actually trigger the software to log in to the remote server, or click Cancel to cancel the login operation. Of course, in some applications there may be a certain part of the processing process is fixed, the user must enter the operation information in the order specified. In order for the user to be guided in the operation, Microsoft has added the concept of a wizard in its software, and this article will discuss how to implement this concept in a later section. It is important to provide feedback on the user's actions in the system in a timely manner, which may be just as insignificant as warning bells or mouse displays as an hourglass, but it allows the user to build confidence that he is still controlling the software without freezing.

2. Provide feedback on several technical means of micro-help. It is the text in the status bar below the MDI (Multiple Document Interface) box. The micro-help in the bottom of the window generally has two functions, one is to display more text information when the user chooses a menu item or other window control to explain or prompt the user what to do, and the other is to show the working state in progress, so that the user can understand the process progress of the system. So as to avoid the fear of freezing.

Help for the tool bar. When you hover over a toolbar, a pop-up message box appears, with the toolbar text displayed by default in the version above 4.0 PowerBuilder. You can also use a menu brush to add a comma to the toolbar text followed by a longer text to define a different toolbar description. For example, type finish shun Bocal row, and we'll see that the text shown on the toolbar icon with text is finish shun relate, and the pop-up message box shows assignment Torr Marsh Tau Row.

Sound hints. It is necessary to use sound to prompt a warning when a user is likely to perform destructive actions, but we cannot abuse it because it is more annoying to hear a warning when the user is unable to operate the software correctly or do something they do not want to do, so use this feedback method with caution. It is also necessary to use sound feedback (such as a warning sound or a small section of Yue) at the end of a long processing.

Use the feedback for the occasion. In the client/server environment The most unbearable is the system response is slow, and in the actual application we will often encounter the computer takes a long time to perform one or a batch of operations. In this case, we should add feedback to let the user know what the app is doing. For example, in the case of short waiting time (0-10 seconds) should be displayed as an hourglass, can call function Setpointer (hourglass!) to achieve this function, in the process of 10-18 seconds, by the micro-help to display the processing progress, when more than 18 seconds, to display this processing window , or display a progress bar; When a long processing time is complete, a warning sound such as beep (1) should be issued so that the user does not have to always look at the screen.

3. Normative and consistent the graphical user interface that we often use, such as Windows, Macs, Xwindow, and so on, provides a standard set of controls that users of frequently used computers may have a great understanding of the purpose of these standard controls, such as a multi-box that changes their state after a user clicks the mouse. When you press the arrow on the ScrollBar, the screen will scroll, and when you click the Radio box, the system will not pop up a dialog box, and if you don't do something like a button or a menu, the system will not go into a new process and so on. After the user has used a large number of applications, the user will be familiar with the operation of the window to establish some basic concepts, when he entered a never used software, will not be helpless, but because the new software and used some applications similar to the use of it has a certain understanding. The higher the level of awareness, the more intuitive the software is, the more successful the software user interface design.
Therefore, every programmer should realize that the application he developed with other programmers is on the same platform, the same window controls are used, and the more users learn about the software in other applications, the more they can apply to the newly developed application. If you use the standard method, users will feel more convenient, although they are not necessarily aware of the reasons for convenience. As a programmer should first understand the role of the different controls in the window, many PowerBuilder programmers have developed applications on DOS or mainframe character terminals, but the GUI of Windows is rather unfamiliar. It is therefore critical that programmers become familiar with what controls to use to accomplish what kind of functionality. When a programmer uses the wrong control, the application cannot be intuitive.
Consistency is an important loop that makes the application intuitive. Consistency includes both the use of standard controls and the use of the same information presentation methods, such as ensuring consistency in fonts, label styles, colors, terminology, error messages, and so on. The following are the conformance criteria that should be followed when displaying information,
* Label hint, font is heavier, Arial, black, gray or transparent, no border. Right-aligned with the colon ending. such as engaged Zhang 簲;
* date, normal font, Arial, white black character, lowered;
* Alignment method,
A. Left alignment, general text, individual numbers, dates, and so on.
B. Right alignment, number, time, date plus time.
The arrangement of this information is mostly controlled by programmers, and the above display style is for reference only, and more importantly, the programmer should pay attention to the consistency of manifestation in the same software. If the information is inconsistent in the same application, the user will be distracted and thus affect the use of the software.
Following the consistency principle above, you should also pay attention to the layout of all controls inside a window and the artistry of the information organization, making the user interface beautiful. In a window to press the TAB key, moving the focus of the order can not be disorganized, under the character interface, such as DOS, the Order of the tab order is first from left to right, then from top to bottom, and in windows in the order generally should first from top to bottom and then from left to right. Controls that should be entered first and foremost in a screen should be in the tab order, and the position should be positioned more prominently in the top of the window.
One of the rules that you should follow in MS Windows Apps is the principle that you can do without a mouse, and that every feature in your app should be done with a keyboard, which means that you should also include some necessary buttons and menu items in your design application. However, many mouse actions, such as double-click, drag objects, and can not be easily simulated by the keyboard can be implemented, such as in a list box with the mouse double-click on one of the items to indicate that the item is selected, in order to use the keyboard can also achieve this function, you must define a button in the window to indicate the selected As an alternative to implementing the double-click feature. If you have two data windows in a window, you can drag one item out of one data window and drop it into another, or you should set the copy or Move menu item in the menu if you use the keyboard only.
Using shortcut keys in a menu item can make it faster for users who use the keyboard, and most of the shortcuts used in western Windows and its applications are consistent.
Transaction-oriented:
* ctrl-d Delete
* Ctrl-f Search
* Ctrl-i Insert
* Ctrl-n New record
* Ctrl-s Save
Query/LIST:
* Ctrl-o
* Ctrl-r
Other: * ctrl-c copy
* Ctrl-h Help
* Ctrl-p Printing
* Ctrl-v Paste
* Ctrl-w off
* Ctrl-x Cut
MSWindows reserved Key: * Ctrl-tab Next window
* Ctrl-esc Task List
* Ctrl-f4 Close window
* ALT-F4 End application
* Alt-tab Next Application
* Enter default button/Confirm action
* ESC Cancel button/Cancel operation
* SHIFT-F1 Context-sensitive Help
These shortcuts can also be used as a standard for developing Chinese applications, but using the initials of Hanyu Pinyin.
4. Secure application software in the development of application software, an important factor is to provide users with a safe working environment, in the software should not have any mines, in the user will be destructive and difficult to restore the operation, the system should give due prompt. Only when the user is fully confident that the software is secure, will they be happy to use it and will be able to explore the new features provided by the software in order to use it more effectively.

What is a secure application
The first and most important, but also the least likely, is to exclude errors that might cause the application to abort abnormally. In any case, the end user should not see the application with a protective error to exit the system, this error is most likely to cause users to lose confidence in the software. Because this means that the user wants to break the train of thought, and time and effort to re-login, and the operation has been done because there is no disk and all lost. Of course, there are many reasons for the system to stop, it may be network, hardware, system software or PowerBuilder itself, but developers should take into account all possible problems, so as to minimize the possibility of error. In particular, software developed with PowerBuilder does often appear to have protective errors, but developers cannot complain about it, but rather do more testing and choose the safest method to achieve the same functionality.
In addition, when using PowerBuilder programming, there is also a common cause of abnormal abort is due to the programmer's own cause, this is the variable join lag problem, that is, at compile time to define a valid object class, However, when the runtime does not create an instance of it or the instance has been freed (destroy), if a piece of code is referenced to this object, the system cannot find its instance in memory, resulting in an abort. Therefore, when referencing a variable, you should first check whether it has an instance, such as an object that references another window in one window, and you should first detect whether it has created an instance before executing the code.
In the following example, the Win_a window object may not be created when the code is executed, so we should use the
IsValid function to check whether it is valid,
IF IsValid (win_a) Then
Close (win_a)
ENDIF
Issues to be noted in using the Data window
The PowerBuilder code will refer to a number of columns in the Data window, and the method of referring to this column can be either a column name or a column number. Column numbers are the sequential numbers that this data window arranges in the execution of a SELECT statement, and if you are accustomed to referencing a column by using column numbers, be aware that you might later move or delete some columns in the SELECT statement in the Data window, and if you can't remember all the code that referenced the data window, In this case, there is a possibility of a data type mismatch error. Using column names to refer to can avoid such errors, but the string used here, at compile time, does not validate that the reference is correct, only at run time, the system may find that the string used does not exist in the data window and powerbuilder the application. This error is generally more difficult to find, and the way to reduce this error is to use object browses as much as possible for clipping to reduce typographical errors.
A secure environment should also be careful to avoid users inadvertently entering invalid data. Under the GUI, there are many controls that can restrict the types of user input values in a very friendly way. For example, a multi-box has only two values to choose from, so when the user has only two possibilities to make a selection, this control can be used, eliminating the hassle of another programming for validation of input validation. When it is possible to choose more, you can use the radio button, each choice is valid, the user cannot enter any invalid choice. In the same way, the ListBox, Dropdowndatawindow, Dropdownlistbox and other standard controls can effectively avoid the user invalid input, but do not have to be programmed for validation, but also to avoid the user at one input point repeated input attempts to delay a lot of time.
In an application, the developer should avoid the user making unauthorized or meaningless operation, in the PowerBuilder the menu and button objects have enabled and visible properties, Therefore, actions that are not authorized or cannot be performed by the user should change the properties of the corresponding objects to disabled and invisible. For example, in a window there is a data Entry window and a delete button. The Delete button is not valid when editing a new record, so the property of the button should be disable. When the state of a window changes, you should change both properties of the control or menu item at any time.
When an object is invalid, using the Disable property or the Invisible property of the control is a personal habit problem. Generally, you should use the Invisible property when a menu item or control is always invalid, such as when a user opens a window with a delete key, but the user does not have permission to delete, and the button should not be visible, and if the user has permission to delete, only in the current state, cannot perform the delete function. If you edit a new record, the button should be set to disable.
　　The Data window is a single Encapsulated object, when you do not want the user to enter a column, the entire data window can not be set to disable properties, but should use other methods, generally speaking, there are the following three ways: The column Tab order is set to 0, The user will not be able to press the TAB key or focus on the column with the mouse. If this method is used, its original taborder value should be stored in an instance variable so that it can be restored when needed. Set the display only or protect property of the column to True. When these two properties are set to True, the column can be focused (as long as the Tab order is not 0), the user can also select some text on the column and horizontal, vertical scrolling, but the value of this column cannot be modified. If a column in a database has a large number of lines that can only be displayed and cannot be modified, this method should be taken into consideration, but it should be noted that the column's tab order cannot be 0, which preserves the user's right to copy part of the content when necessary. ² Set the Visible property of the column to False. This column automatically sets the Tab order to 0 and does not focus. When this value is changed to True, the value of Tab order can still be restored. The disadvantage of this approach is that the screen flashes when the property is changed, so this method cannot be abused.  ² the error message of the system as much as possible is the important factor that makes the user feel secure. Developers should anticipate some possible errors, as far as possible to avoid the system default error messages appear, on the one hand, because the information itself is not Chinese, and too professional, the user is not easy to understand, on the other hand it is easy to make users think their own operation errors, resulting in insecurity. For example, a user may violate the constraints of the database when entering data, and the developer should verify the necessary validation of the PowerBuilder before issuing the SQL statement to the database before submitting it. Of course, the use of a drop-down list box and other methods can implement foreign key constraints. If the user enters directly from the keyboard, it is necessary to verify the validity of the data before it is update. Some columns in the database have non-empty constraints, and if the user commits the database when the data is not populated with some columns, it also returns an error, so when the developer designs the window, the non-null constraints of the database should be previewed first, so that the error messages from the DBMS are not displayed directly to the user. Also, before using the Data window, make sure that each column is selected in the Update option (in the Data Window Brush menu, rows| UPDATE), the column will not be included when the system does the update and insert operations in DataWindow. In PowerBuilder, the Required field property of the Data Window Brush column is an unfriendly property of the interface. Once focused on the column, there is no lossThe column does not have a value when it leaves or submits the data window, and the system is not allowed. Even if you do not know what to enter, you want to query the other windows, you have to write something in this column, in order to close the Regiment this window, so it is not recommended to use this property, but to be programmed to do the check, you can put this code in the Updatestart event, this event in the implementation of update () function is triggered.
Users should be prompted appropriately before the user has to make a hard-to-recover operation, so there is no worry when the user intends to explore new features of the system. For example, users inadvertently delete some records to restore them is difficult, so before users delete, out a prompt window and so on. Before the system modifies the record but does not save the disk, it should be in the Closequery event prompt and other information.

Interface design and test specifications