DEVELOPING DATABASE APPLICATIONS (INTERMEDIATE MICROSOFT ACCESS, X405.5)

Transcription

1 Technology & Information Management Instructor: Michael Kremer, Ph.D. Database Program: Microsoft Access Series DEVELOPING DATABASE APPLICATIONS (INTERMEDIATE MICROSOFT ACCESS, X405.5) Section 6

2 AGENDA 19. Advanced Form Controls 20. Text Box Control 21. Combo/List Box Control

3 Advanced Form Controls 19.

4 19.1 CREATING LAYOUTS FOR CONTROLS 249 Layouts are formatting containers to group controls in a specific fashion. Layouts are guides that align your controls horizontally and vertically to give your form a uniform appearance. Overview of Control Layouts There are two different layouts: Tabular and Stacked. A tabular layout groups controls in a horizontal manner which is useful for continuous forms (multiple records). A stacked layout is a vertical layout which groups controls in a column.

5 19.1 CREATING LAYOUTS FOR CONTROLS 250 Within these two main formats, you can split or merge cells to customize the layout to better suit your controls. A tabular layout moves the control s label in the header section of a form or report, very much like a spreadsheet. At this point, the labels are severed from the controls. A stacked layout moves the labels to the left with the data controls to the right. Stacked layouts are always contained within a single section on the form or report. Working with Control Layouts To create a tabular layout, simply select the controls and click on the Tabular button in the Form Design Tools ribbon, Arrange tab. You can also create multiple layouts in one form.

6 19.1 CREATING LAYOUTS FOR CONTROLS 251 To move controls from one layout into the other simply drag a control over to the other layout. To remove a control from a layout, simply select the control and click on Remove in the Table group of the Arrange tab. Split or Merge Cells in a Control Layout Like a table in a word processing document, a layout is made up of cells that are arranged in rows and columns. Each cell can contain one control, such as a text box, a label, or a command button. You can split one cell horizontally or vertically to create two cells, or you can merge multiple cells together to create one large cell that spans multiple rows or columns in the layout.

7 19.1 CREATING LAYOUTS FOR CONTROLS 252 Follow these steps to merge cells: 1. Select the first cell that you want to merge. 2. Hold down the SHIFT key and select the other cells that you want to merge. 3. On the Arrange tab, in the Merge / Split group, click Merge.

8 19.2 ANCHORING CONTROLS 253 Another new feature since Access 2007 is the Anchor feature. This feature allows controls to grow or shrink as the form window is resized.

9 19.2 ANCHORING CONTROLS 254

10 19.2 ANCHORING CONTROLS 255

11 19.2 ANCHORING CONTROLS 256 Special considerations must be given when you use anchoring in control layouts. Control layouts are table-like grids that group multiple controls together so that they are automatically sized and aligned. You can specify the anchoring for only one control in each layout.

12 19.3 BOUND, UNBOUND, CALCULATED CONTROLS 257 There are three different types of controls, bound, unbound and calculated. The customerid field on the form frm_example5_2 is a bound control. It is linked or bound to the CustomerID field in the customer table. It displays the information stored in the database for that particular field on the form. The connection from the control to the database is a two-step process.

13 19.3 BOUND, UNBOUND, CALCULATED CONTROLS 258 First of all, the form itself must be bound to some data source, either a table, a query, or a SQL statement stored in its RecordSource property. Based on the data source, the ControlSource property of a control links a control to a specific field. To identify whether a control is bound, unbound or calculated select the data tab of the property sheet. Controls which do not have an entry in the Control Source property are unbound controls.

14 19.3 BOUND, UNBOUND, CALCULATED CONTROLS 259 Unbound data bearing controls are used for entering information on a form, which in turn, is then used for calculations or criteria expressions. Unbound controls are useful as temporary memory spaces on the form to hold values. Non data bearing controls are by definition unbound since they cannot display any database information. The following controls are unbound controls by design: Labels Lines, Rectangles Command buttons. Image, Unbound Object Tab Control

15 19.3 BOUND, UNBOUND, CALCULATED CONTROLS 260 A control is a calculated control if the ControlSource property contains an expression composed of database fields or functions.

16 19.3 BOUND, UNBOUND, CALCULATED CONTROLS 261 When you do not type the equal sign in front of the Date() function inside the ControlSource property of an unbound text box control, you will notice a small green triangle in the upper left corner of the text box when you leave the control. This is a feature called error checking. When you select the control again, you will see the smart tag symbol, selecting it opens a drop-down list with an explanation of the error and other options. Configure in Access Options.

17 Text Box Control 20.

18 20.1 OVERVIEW OF THE TEXT BOX CONTROL 262 Text box controls are the most used controls on forms and reports. Text box controls are compound controls, when created, a label control is automatically attached to the text box control. Text box controls can be used to display almost any data from the database. Besides ShortText and LongText fields, all number fields and date/time fields can be used as a source for a text box control. Hyperlink, Currency, Autonumber, and Yes/No fields are also suitable for text box controls. Furthermore, text box controls are used as unbound controls as well as calculated controls.

19 20.2 CREATING TEXT BOX CONTROLS 263 Text box controls can be created in two different ways. First, using the Controls group in the Design tab of the Form Design Tools ribbon and clicking on the text box control button. The second method entails using the field list button in the Tools group and dragging the field onto the form. Follow these steps to create a bound text box using the field list button located in the toolbar: 1. Open a form in design view. 2. Click on the field list button in the Tools tab, the field list is now displayed as a floating window in design view. 3. Select a field or multiple fields ([Shift] or [Ctrl] click) and drag the selected fields onto the form. 4. Close the field list window.

20 20.2 CREATING TEXT BOX CONTROLS 264 To create a text box control using the control section in the Ribbon: 1. Click on the Form Design Tools ribbon, then the Design tab. 2. Click on the text box control button (do not hold the mouse button) in the controls group. 3. Move the mouse onto the form in design view. Note the mouse pointer shape consists of a thin cross with a text box control icon attached. 4. Drag a rectangle on the form to create the text box control. 5. To bind the control, display its property sheet, and select a field in the ControlSource property from the underlying data source. Using the field list is the preferable way to create bound controls on forms and reports for two major reasons: Label controls either display the field name or the caption property of the field. The text box control inherits some property settings from the underlying table or query.

21 20.2 CREATING TEXT BOX CONTROLS 265 These are the properties inherited from the underlying table or query: Format Decimal Places Input Mask Status Bar Text (from Description property) Caption

22 20.2 CREATING TEXT BOX CONTROLS 266 The DefaultValue, ValidationRule, and ValidationText properties are not inherited by controls in forms. When dragging a field of data type LongText from the field list onto the form, the Text Box control is automatically sized wider and taller to visually indicate that the field is a LongText field.

23 20.3 CALCULATED TEXT BOX CONTROLS 267 To create a calculated control, click the appropriate control on the toolbox and place it onto the form. Then display the properties, select the data tab, and enter an expression in the Control Source property. IMPORTANT: Precede the expression with an equal sign(=). When using derived or calculated controls on your form, you have to understand how MS Access uses references on a form. Access first searches the form object for a reference (example [City], if it cannot find it, then it goes to the underlying data. This can lead to confusion, therefore, name controls using prefixes.

24 20.3 CALCULATED TEXT BOX CONTROLS 268

25 20.4 TEXT BOX CONTROL PROPERTIES 269 Each control on a form has its own properties. Besides the overall form properties and the individual section properties (Form header, detail section, Form footer), all controls have properties. Text Box Format Properties Contains some field properties which can be overridden at the form level.

26 20.4 TEXT BOX CONTROL PROPERTIES 270

27 20.4 TEXT BOX CONTROL PROPERTIES 271

28 20.4 TEXT BOX CONTROL PROPERTIES 272

29 20.4 TEXT BOX CONTROL PROPERTIES 273

30 20.4 TEXT BOX CONTROL PROPERTIES 274

31 20.4 TEXT BOX CONTROL PROPERTIES 275 Text Box Data Properties Properties that affect its data binding mechanism plus overriding certain field-level properties.

32 20.4 TEXT BOX CONTROL PROPERTIES 276

33 20.4 TEXT BOX CONTROL PROPERTIES 277 Text Box Event Properties Event properties are used to link macros or VBA code to respond to an event. There are form-level, section-level, and control-level events. At the control level the most important events are the Update events (Before, After, Dirty, Change, Undo) and the focus events( Enter, Got Focus, Lost Focus, Exit).

34 20.4 TEXT BOX CONTROL PROPERTIES 278 Text Box Other Properties Like with form properties, the Other tab contains some miscellaneous properties.

35 20.4 TEXT BOX CONTROL PROPERTIES 279

36 20.4 TEXT BOX CONTROL PROPERTIES 280

37 20.4 TEXT BOX CONTROL PROPERTIES 281 Setting Tab Order Access sets the tab order for the controls in the order in which you place the controls on the form. If you want to change the tab order that Access created, you can set a different tab order. In Form design, select the Detail area (or any control in the Detail area), and then click the Tab Order button in the Tools group on the Design tab to open the Tab Order dialog box.

38 20.4 TEXT BOX CONTROL PROPERTIES 282

39 20.4 TEXT BOX CONTROL PROPERTIES 283 Setting Properties for Multiple Controls To change the properties of several controls at once, follow these steps: 1. Select the desired controls. 2. Display the property sheet. 3. Change the properties. The Selection Type of the property sheet reads Multiple Selection since it displays properties of several controls at once. Only displays properties that selected controls have in common.

40 20.4 TEXT BOX CONTROL PROPERTIES 284 Setting Default Properties To view the default properties of a control, follow these steps: 1. Select a control in Form design, for example a text box. 2. In the Design tab of the Form Design Tools ribbon, select the text box control. 3. The default properties are displayed in the property sheet. 4. Note that it reads in the Selection Type: Default Text Box (for a text box, for example). To change some or all default properties for a given control: 1. Create a control type on a form for which you want to set the default properties. 2. Change property settings as desired. 3. To save these settings, click on Set Control Defaults in the Controls group of the Design tab.

41 Combo/List Box Controls 21.

42 21.1 OVERVIEW OF LIST/COMBO BOX CONTROLS 285 The List and Combo box control are special controls in that they can display data from other tables or queries. These are the only two controls with a RowSource property similar to the form s RecordSource property. The data for a List or Combo Box control can be derived from a table or query, additionally the data can be also stored in the control itself. The main differences between the List Box and the Combo Box: A List Box control can display multiple rows and columns at all times, whereas a combo box displays one row and one column at all times. Only when you click on the drop-down arrow, multiple rows/columns are displayed. A List box control is limited to the values based on the underlying data source, whereas a combo box is not (LimitToList property). The List Box control allows for a multiple-selection feature (more than one row can be selected), whereas the Combo box control only allows for one row to be selected. However, to take advantage of this feature, the List box must be unbound and macros and/or VBA code must utilized.

43 21.2 NAVIGATIONAL COMBO/LIST BOXES 286 A combo or list box control may replace the navigation buttons at the bottom of the form. The built-in wizards allow you to create a combo or list box control to select records of the underlying form in order to navigate to the selected record. The first two options enable data lookups whereas the last option is used for building a navigational combo/list box control.

44 21.2 NAVIGATIONAL COMBO/LIST BOXES 287

45 21.2 NAVIGATIONAL COMBO/LIST BOXES 288

46 21.3 LOOKUP COMBO/LIST BOXES 289 The most useful feature of the Combo/List box control is its ability to display data from a data source other than the underlying data source on the form. Looking up data is the most common use of Combo/List box controls.

47 21.3 LOOKUP COMBO/LIST BOXES 290

48 21.3 LOOKUP COMBO/LIST BOXES 291

49 21.4 COMBO/LIST BOX PROPERTIES 292 The new properties of the List and Combo box controls are listed and explained in this chapter. Combo/List Box Format Properties

50 21.4 COMBO/LIST BOX PROPERTIES 293 Set the List Width to at least the sum of the column widths, otherwise you might get horizontal scrollbars in your drop-down list. In the SQL statement for the RowSource property, make sure to include the key column as the first column as this column will be stored in the control by default when a row is selected in the drop-down list. The Bound Column property is set to 1 by default, which means the first column is used to store in the control.

51 21.4 COMBO/LIST BOX PROPERTIES 294

52 21.4 COMBO/LIST BOX PROPERTIES 295 Combo/List Box Data Properties

53 21.4 COMBO/LIST BOX PROPERTIES 296

54 21.4 COMBO/LIST BOX PROPERTIES 297 Edit List Items Combo/List Box Event Properties An additional event exist: NotInList. Combo/List Box Other Properties

55 21.4 COMBO/LIST BOX PROPERTIES 298