Using Data Controls

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The Data Controls category of the Tool palette provides a set of data-aware controls that represent data from fields in a database record, and, if the dataset allows it, enable users to edit that data and post changes back to the database. By placing data controls onto the forms in your database application, you can build your database application's user interface (UI) so that information is visible and accessible to users.

The data-aware controls you add to your user interface depend on several factors, including the following:

• The type of data you are displaying. You can choose between controls that are designed to display and edit plain text, controls that work with formatted text, controls for graphics, multimedia elements, and so on. Controls that display different types of information are described in Displaying a Single Record.
• How you want to organize the information. You may choose to display information from a single record on the screen, or list the information from multiple records using a grid. Choosing How to Organize the Data describes some of the possibilities.
• The type of dataset that supplies data to the controls. You want to use controls that reflect the limitations of the underlying dataset. For example, you would not use a grid with a unidirectional dataset because unidirectional datasets can only supply a single record at a time.
• How (or if) you want to let users navigate through the records of datasets and add or edit data. You may want to add your own controls or mechanisms to navigate and edit, or you may want to use a built-in control such as a data navigator.

Regardless of the data-aware controls you choose to add to your interface, certain common features apply. These are described in Using Common Data Control Features.

Topics

• Using Common Data Control Features
  • Associating a Data Control with a Dataset
    • Changing the Associated Dataset at Runtime
    • Enabling and Disabling the Data Source
    • Responding to Changes Mediated by the Data Source
  • Editing and Updating Data
    • Enabling Editing in Controls On User Entry
    • Editing Data in a Control
  • Disabling and Enabling Data Display
  • Refreshing Data Display
  • Enabling Mouse, Keyboard, and Timer Events
• Choosing How to Organize the Data
  • Displaying a Single Record
  • Displaying Data as Labels
  • Displaying and Editing Fields in an Edit Box
  • Displaying and Editing Text in a Memo Control
  • Displaying and Editing Text in a Rich Edit Memo Control
  • Displaying and Editing Graphics Fields in an Image Control
  • Displaying and Editing Data in List and Combo Boxes
  • Displaying and Editing Data in Lookup List and Combo Boxes
    • Using TDBListBox and TDBComboBox
    • Handling Boolean Field Values with Check Boxes
    • Restricting Field Values with Radio Controls
    • Displaying Multiple Records
  • Viewing and Editing Data with TDBGrid
    • Using a Grid Control in Its Default State
    • Creating a Customized Grid
      • Creating Persistent Columns
      • Deleting Persistent Columns
      • Arranging the Order of Persistent Columns
      • Setting Column Properties at Design Time
      • Defining a Lookup List Column
      • Putting a Button in a Column
      • Restoring Default Values to a Column
    • Displaying ADT and Array Fields
    • Setting Grid Options
    • Editing in the Grid
    • Controlling Grid Drawing
    • Responding to User Actions at Runtime
  • Creating a Grid That Contains Other Data-aware Controls
  • Navigating and Manipulating Records
    • Choosing Navigator Buttons to Display
    • Displaying Fly-over Help
    • Using a Single Navigator for Multiple Datasets

See Also

• Designing Database Applications
• Understanding Datasets Index
• Working with Field Components - Overview
• Using Client Datasets - Overview
• Connecting to Databases - Overview
• Working with ADO Components
• Using dbExpress Datasets
• Using the Borland Database Engine
• Using Provider Components
• Creating Multi-tiered Applications - Overview
• Using XML in Database Applications