A ComboBox graphical element allows users to select items from a predefined list.
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Requirements
This component is Portable. It runs both on Windows and on Web Pages hosted in any platform.
Configuration
- Go to Displays / Draw.
- On the Components Panel, select Interaction, then ComboBox.
- Click or drag-and-drop it on the Drawing area to use it.
- Double-click the component to open the configuration window.
Combo Box Settings | |||
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Field | Description | ||
LinkedValue | Specifies the variable or tag to which the ComboBox is bound. Ensures that the selected value in the ComboBox is linked to the specified data source, enabling dynamic updates and data binding. | ||
Binding | Sets the binding mode for the component. Options are: TwoWay: Updates the data source and UI interchangeably; OutputOnly: Allows data output without user input; InputOnly: Accepts user input without updating the data source. | ||
SelectedIndex | Specifies the index of the currently selected item in the ComboBox. Allows the application to track the selected item and update other components accordingly. | ||
Items Source | Determines the source of the items displayed in the ComboBox. Options are: Designer: Allows the ComboBox to display a list of simple text items , configured in the designer. StringTag: Tag with ComboBox items separated by ';' semi-colon. ArrayTag: Allows the ComboBox to display items from an array. DataTable: Allows the ComboBox to display items from a collection of objects. . | ||
Is Editable | Allows users to type in the ComboBox to add new items or select existing ones when selected. This feature is useful in scenarios where predefined options are insufficient. | ||
Start Index at One | Sets the index counting to start at one instead of zero when checked. Useful for user interfaces where the indexing needs to align with non-programmatic conventions. | ||
MaxItemsReload | Specifies the maximum number of items that the ComboBox can display or hold. Limits the number of items to prevent overload and improve performance. | Reload | Specifies a command or function that reloads the items in the ComboBox. Ensures that the ComboBox displays the most current data, useful for dynamic or real-time data sources.a command or function that reloads the items in the ComboBox. |
DataTable Items Source
When using a DataTable as the Items Source, the value can be from a DatasetQuery, or a DatasetTable, a DataTable Tag, or an Array Tag of DataTemplates.
When using Dataset Table or Queries, there is no needing to call the Select(), the ComboBox will call the Select() to the Table or Query when initializing.
In order to define which column from the Database will populate the ComboBox, there are 2 options:
- Using the DisplayMemberPath and SelectedValuePath
- Using the Element UId or First Column
DisplayMemberPath and SelectedValuePath
The DisplayMemberPath is the name of the Column in the source table, that will populate the ComboBox.
TheSelectedValuePath is the name of the Column in the source table, that will be assigned to the LinkedValue when the selection changes.
When both elements are defined, and the source table contains those columns, the system uses this configuration to populate the ComboBox. Otherwise it will use the UId of the element, or the
Element Uid or First Column
The UId is the element identification defined in the Properties SideBar.
If there is a column in that table that matches that Uid, the contents of that column, converted to string, is used to populate the ComboBox.
When that column is not found, the first column is used.
Runtime Execution
When users select an item from a combo box, the application updates to reflect the chosen option. This selection changes the displayed data or configuration settings according to the user's choice. The combo box helps users choose from predefined options, such as a machine type or report format.
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