
- Form
A window provided for easy data entry and presentation on the computer screen.
- Form's data source
Database table or query providing data displayed in the form. The data source is needed because forms itself are only tools for displaying and entering data, while tables and queries are the source of data. New, empty forms have no data source assigned, so they are not displaying any data from your database unless you assign a data source to them.
- Form field
Direct equivalent of a column in a table or query. Most frequently used are fields for displaying text and numbers. Entering a new value or changing the existing value of such a field causes a change in the bound table or query column (after accepting the change).
- Form design
Tasks you are performing to define the appearance and functions of the form. To do this, you need to provide data source, insert form fields of various types and place them at the appropriate location.
- Form widget
Form's element. Main widget types are:
Widgets displaying information, e.g. a text box or an image box. Each widget of this type can be bound to a data source field (a table or a query column). Therefore, such widgets are called in short form fields.
Widgets able to perform a specified action, e.g. a push button that can close the current form. Within other applications this widget type is sometimes called form control because it can perform previously defined action of controlling your database application's behavior.
Other widgets allowing to enrich a form's appearance, e.g. a “line widget” can visually separate two form areas.
- Container widget
A widget that can contain other widgets within its area. For example, frame widget or tab widget are containers. The form's surface itself is a container as well. A command button cannot be called as container because it is not possible to insert a widget inside it. In more complex cases, container widgets can be inserted inside a container, so nesting is possible.
In chapter 5.2 you learned about how to enter data directly into tables using their data sheet view. However, in many cases forms are better suited for data entry:
A table can contain too many columns to display them on your screen. A form can display such a data using multiple rows.
A form allows to visually split data fields into logical groups, thus increasing readability. Labels with additional information can be inserted to give users more hints on how to use the form or what given data fields mean.
Command buttons can be used within forms for commonly used commands so users can use forms in a similar way as a standalone applications they know.
In data sheet view displaying multi-row data text fields or images is as easy as within forms.
As with table or query design, you are able to use Data View and Design View. Form designing is performed in Design View. We will often refer to the form design window as to Form Designer.
To create a new empty form, select → from the Menubar. Optionally, you can use command from drop-down button on the Project Navigator's toolbar or command from the context menu.
A new frame will appear, you can resize the form by moving the borders. The form is covered with a grid which simplifies accurate positioning of the widgets.
As with table design, Form Designer provides Property pane. To save some space on the screen, the pane has three tabs related to the currently selected form:
- The Properties tab
Contains a list of properties for the currently selected widget.
- The Data source tab
Contains properties related specifically to the data source of the currently selected widget or the form itself.
- The Widgets tab
Contains a hierarchy of all widgets of the form. The list simplifies widgets lookup by name and navigation between them.
There is information about currently selected widget's name and type displayed on the first and second tab.
Additional toolbars are also available:
The Widgets toolbar used for inserting new widgets into the form
The Format toolbar used to format form's elements (e.g. adjusting widget's size, grouping). Formatting commands are also available in the menu. More about these commands can be found in the section called “The Menu”.
The Widgets tab in the Property pane provides a list of form widgets and their hierarchy. Each widget is presented within the hierarchy beside other widgets being on the same level (the same parent container). Child widgets (inside containers) are presented using indented names.
Each widget has displayed its name and type. The type has also an icon displayed - the same as the one displayed on the toolbar used while form designing is performed.
Note
Changing the current selection on the list causes appropriate selection on the designed form. This allows for easier widget lookup by name and easier navigation. For example, it is possible to select a widget by name, and then switch to the Properties tab to change the widget's properties.
Keeping the Ctrl key pressed while an item on the widgets list is being selected allows to select multiple widgets at a time. Keeping the Shift key pressed allows to select entire lists of widgets.
Giving widgets reasonable names can be useful but is not mandatory. Note
that widget's name is a property that is not visible to the user of your form.
Users will only see a widget text, provided by Text
property
or similar.
Let's create a form providing information about persons, i.e. a form connected
it with Persons
table.
If the form being designed should present data obtained from the database, you need to place appropriate fields on it. To do this, use the buttons on the Widgets toolbar. Each button corresponds to a single widget type.
Click button on the Widgets toolbar.
Click on the form surface with the
mouse button. A new text box widget will be placed in the point where you clicked. Before you release you can drag your mouse to specify a desired size for the widget.If needed, move the inserted widget using drag & drop to a desired position. You can resize the widget afterwards by dragging one of the small boxes appearing near its corners. Note that the boxes are only visible when the widget is selected. If you select another widget or the form surface, the boxes disappear.
Click the toolbar button again and click on the form surface to insert another widget. Repeat this action once again until you get three text boxes inserted in your form. For sake of simplicity we will limit ourselves to three data fields.
Note
There is a context menu available in form's design mode, activated by a , , , and other, more complex. Many of the commands are also provided in the Menubar, usually . Keyboard shortcuts are also available for these commands. Some of the commands are only available for certain types of widgets.
mouse button click the desired widget or the form's surface. The menu offers commands likeThe commands , and makes it possible to move or copy widgets between forms, even between separate database projects.
Holding the Ctrl key down while clicking a widget allows to select multiple widgets.
Instead of using and commands, to duplicate a widget within the same form you can hold down the Ctrl key while moving the widget. After the Ctrl key is released, the dragged widget will not be moved but copied in the new location.
The fields you inserted have no data source assigned yet, so these are not able to display information from the database. To assign data source, use the Data Source tab of the Property pane.
The very first step is to specify the form's data source,
i.e. a place the displayed data will be fetched from. As mentioned above, you
will use table persons
as a
data source
for your new form.
Click on the form's surface, as you will alter its properties.
Switch to the Data Source tab and enter
persons
table name in the Form's data source drop down list. Alternatively, you can select this name from the drop down list.
You have assigned form's data source. Now you need to do specify widget's data source.
Click the first text field widget at the top of the form.
In the Data Source tab of the property pane enter field name
name
in the Widget's data source drop down list. Alternatively, you can select this name from the drop down list.Click on next text field widget and enter
surname
as the data source.Enter data sources for
street
,house_number
andcity
text fields in a similar way.
You can now save the form's design (this is not mandatory to test the
form in action). To save, click the
Save object changes toolbar button or use the
→ (Ctrl+S)
menu command. Upon saving you will be asked for entering the form's name. Enter
Persons
as caption and click the
button. The form's name will be filled automatically.
This is the right moment for testing your form. Click the
toolbar button. Unless you made a
mistake while entering data sources, you should see
form's fi elds filled
with data from the persons
table.
Note
If you want to remove widget's data source assignment for a form widget, you can use button near the Widet's data source drop down list. Similarly, you can use the button near the Form's data source drop down list.
Use the button to select appropriate table or query in the Project Navigator, so you can quickly open a table or query being the data source of the form.
To make it easier for the form's user to identify the meaning of every field
widget, these should have added text labels with appropriate titles. To
create text labels the
Label
widget is used.
Insert three text label widgets onto the form, placing them on the left
side of the text fields (or on the right hand if your operating system
uses right-to-left layout). On inserting a new label, a text cursor
appears at the location where you can enter the desired title. Enter consecutively:
Name
, Surname
and Street
. Additionally,
on the top of the form insert another label displaying name of the form,
i.e. Persons
. Enlarge this label's size and and increase the font size using
→
menu command.
An Action
is a single activity isolated in the application,
available for the user to execute. It can also be executed automatically as a
reaction for a given event (e.g. after opening a form).
Many actions can be assigned to form button. The assigned action is executed after button is clicked.
To assign action:
Switch to form's Design view if you have not done yet.
Select the existing button widget by clicking on it or put a new button widget onto the form. If you inserted a new button, enter its title and press Enter key.
Click the button widget with the
mouse button to display the context menu.From the context menu select command.
An Assigning Action to Command Button dialog window will appear presenting a list of available actions. One of the actions is selected if the widget already has action assigned. Otherwise the Action type drop down list has the No type item selected.
From the Action type drop down list select Application item. Available application-wide actions will be listed.
Select one of the actions on the list (e.g. Delete Row).
Click the button or press the Enter key to accept your selection.
After switching to the form's data view you can try whether the action works. For example, if you assigned Delete Row action, clicking the button, the current database row will be deleted, similarly to executing → (Ctrl+Delete) menu command (depending on your settings you may be asked to confirm the removal).
Note
To remove an action assignment, select No type item from the Action type drop down list of the Assigning Action to Command Button dialog window.
Actions only work in the form's data view. Not every action's assignment is reasonable. For example, the action is available in data view, but only if you have a widget selected in the Design view. If you make changes to the font settings the changes are applied to the text of that selected widget.
In most cases form widgets should be conveniently arranged and aligned. Positioning, aligning and resizing widgets by hand is not easy and these parameters are not adjusted when the user resizes the form. In fact the situation is even worse because you cannot assume a given form requires a given space because users have different font sizes and display resolutions.
Using special tool called widget layouts can help to automatically lay out the form widgets. Widget layout is an action of grouping two or mor e widgets so these are well positioned and have appropriate sizes.
Using layout in a form improves alignment. Moreover, its space is better used. Text fields are closer to each other, spacing is constant.
There are two methods to create widget layout.
Select two or more widgets that should be placed in a common layout, and select one of the layout types from the context menu item Layout Widgets .
Click a container widget (or a form surface itself), where widgets are inserted and select one of the layout types from the context menu item Layout Widgets . All widgets existing within the container or within the form, being on the same level will be put into a single common layout.
In each of these cases you can also use → menu.
Widget layout is presented in the design view using a blue, green or red box drawn with a broken line. This line is displayed only in the form's design view.
Besides the grid type, there are other widget layout types.
- vertical
Vertical widget layout
- horizontal
Horizontal widget layout
A spring in widget layouts is a special, invisible element allowing to adjust widget's position and size within layouts. Such a spring stretches or squeezes a widget on the right, top, bottom or left hand, so it can have desired size and position.
To use a spring:
Select spring icon on the Widgets toolbar.
Click on a selected point of the form to insert the spring.
To make springs work you need to create a global widget layout, i.e. a layout for the form itself. Then, springs can use edges of the form as a boundary for expanding.
To remove widget layout without removing widgets, perform one of these actions:
Click with the command from the context menu.
mouse button on the layout's border and selectClick with the → menu command.
mouse button on the layout's border and select
Note
Removing widget layout using the command will not remove widgets contained in the layout. If you want to remove the widgets as well, just select the layout by clicking on its border and press Delete key or use →