Besides the rich data presentation functionalities as demonstrated in previous section, TDataGrid is also highly user interactive. An import usage of TDataGrid is editting or deleting rows of data. The TBoundColumn can adjust the associated cell presentation according to the mode of datagrid items. When an item is in browsing mode, the cell is displayed with a static text; when the item is in editting mode, a textbox is displayed to collect user inputs. TDataGrid provides TEditCommandColumn for switching item modes. In addition, TButtonColumn offers developers the flexibility of creating arbitrary buttons for various user interactions.
The following example shows how to make the previous book information table an interactive one. It allows users to edit and delete book items from the table. Two additional columns are used in the example to allow users interact with the datagrid: TEditCommandColumn and TButtonColumn.
TDataGrid supports sorting its items according to specific columns. To enable sorting, set AllowSorting to true. This will turn column headers into clickable buttons if their SortExpression property is not empty. When users click on the header buttons, an OnSortCommand event will be raised. Developers can write handlers to respond to the sort command and sort the data according to SortExpression which is specified in the corresponding column.
The following example turns Example 2 into a sortable datagrid. Users can click on any link button displayed in the header of a column and the data will be sorted in ascending order along that column.