Dapfor .Net Grid is a hierarchical WinForms control with single or multiple headers. The grid can display data of various types from various sources. Data can be displayed with or without hierarchy. Supported .Net frameworks: 2.0, 3.0, 3.5, 4.0

Data presentation without hierarchy.

Single header used for all hierarchy levels.

Multiple independent headers.

The method of data presentation depends on the number of headers in the grid. Upon display of each row the grid searches for a header for it, and if it doesn't find it, a header from the previous hierarchy level is used. This enables to implement the grid and tree listview in a single component.

Header header1 = new Header();
header1.Add(new Column("Id1", "Column 1"));
header1.Add(new Column("Id2", "Column 2"));

Header header2 = Header.FromDataType(typeof(SomeClass));

grid.Headers.Add(header1);
grid.Headers.Add(header2);

Every header consists of two panels: the column panel and the grouping panel. The column panel displays all visible columns each of which defines width of data displayed in cells.

User may modify column width, move columns, modify their visibility and group data by dragging visible columns to group panel. By clicking a column user may turn on data sorting. Holding Ctrl key enables multiple sorting and Shift + left click cancels sorting. All these operations are also available in the context menu that
opens upon right-clicking in header area.

Grid columns can be easily freezed on any hierarchical levels. On program level it is done via Header.FixedColumns.Count = ‘count of freezed columns'. All grid content to the left will not be scrollable.

Grid content is displayed as rows containing cells. Cells in a row are determined by header that belongs to the same hierarchy level as the row, and if there is no header, a header from the previous level is used.

The grid may contain multiple selected rows and one focused row. It is necessary to distinguish these two concepts. A row can be selected and focused at the same time, but selection is row property and focus is grid property. The end user may navigate the grid using Up/Down/Left/Right/PageUp/PageDown/Home/End keys. Focused and selected rows are changed during navigation. If user holds the Shift key during navigation, all rows between the previous focused row and the new focused row become selected. If user holds only Ctrl key, it changes only focused row and selection doesn't changed. Rows can also be selected by left-clicking with Ctrl and Shift keys having the same effect.

Row indexing

The grid provides a lot of ways to define place for storing data and business objects in hierarchical grid structure. Grid rows may be visible or filtered and may connect child rows that may in turn be visible, filtered or collapsed by their parent row. Every row has multiple indices that define its precise position. The grid also provides 2 collections that contain the same rows organized in different ways. Grid.Rows contains only visible rows disregarding their hierarchy level. Grid.Nodes contains all rows of the top hierarchy level disregarding their visibility. The figure below illustrates row indexing in the grid.

If there are multiple filtered rows at the same hierarchy level, Row.ChildIndex and
Row.VisibleChildIndex may differ. Rows can be moved programmatically by assigning new row index. Row.VisibleIndex doesn't specify row location unambiguously because it doesn't consider hierarchy. Therefore, it is read-only.

Row row = grid.Rows[10];
//Move to the first position 
row.ChildIndex = 0;

//Move to the first visible position (note: some previous rows can be filtered)
row.VisibleChildIndex = 0;

Data in the grid

The grid works with different types of data and provides a lot ofmethods for adding data (to any hierarchy level). Main methods of adding data:

• Binding via a data source Grid.DataSource = ‘data source'. IList, IBindingList, IListSource may be used as data sources. When IListSource is used, data can be added from multiple IBindingList sources.
• Binding in any grid row. Row.DataSource = ‘data source'. IList, IbindingList may also be used as data sources.
• Unbound mode. i.e. adding rows on program level without collections: Grid.Rows.Add(...), Row.Add().
• Conditional binding that raises Grid.RowAdding event when data is added (or via Grid.DataSource/Row.DataSource ???? Grid.Rows.Add(…)/Row.Add()). In conditional binding programmer may replace a business object with any other object and define method of adding it to the grid and relevanthierarchy level.

It is worth mentioning that it is possible to combine these methods of adding data ensuring maximum flexibility.

Data in the grid may be of various types. It may be objects of arbitrary classes, object[]/string[] or objects implementing IList, IDictionary and other interfaces. These objects may be collected in IBindingList or added to the grid with Grid.Rows.Add()/Row.Add() methods. Objects of arbitrary classes have a special role. Properties of such objects usually correspond to column identifiers and the objects by themselves are contained in grid rows. If desired, it is possible to modify property identifiers using attributes.
It is worth mentioning that the same objects may be located in multiple grid rows in the same time.

public class Instrument
{
   ...

    [Field("InstrumentId")]
    public string Isin
    {
        get { return _isin; }
    }
}

Header header = new Header();
header.Add(new Column("InstrumentId", "Instrument"));

grid.Headers.Add(header);
grid.Rows.Add(new Instrument());

INotifyPropertyChanged interface

The grid supports objects that implement INotifyPropertyChanged interface. Such objects may notify the grid of changes in object property values. The grid subscribes to events, performs multi-threaded synchronization when needed and automatically sorts, filters and regroups rows that contain business objects that have notified the grid. These objects may be stored in IBindingList or added via Grid.Rows.Add()/Row.Add() methods. Disregarding the method of adding data to the grid it subscribes to objects that implement this interface and performs automated sorting, filtering etc.  It is recommended to implement INotifyPropertyChanged for implementing application business logic. This approach enables significant reduction of code volume, making the code simpler and implementing modern programming patterns (such as MVVM) to separate business logic from its presentation.

Data highlighting

One of the most convenient grid features is highlighting cells with specified color for a certain period of time. This feature is often used by traders and requires significant time and good understanding of grid operation to implement. Cell highlighting is actually modification of its background color for a certain period of time followed by restoration of this color. Regular implementation involves a timer and storage of timestamps for each modified cell. This requires attention to memory and CPU resource consumption. It is almost impossible to create optimal
highlighting implementation without good understanding of GDI/GDI+ and grid implementation specifics. This causes excessive waste of computer resources and programmer's time.

NetGrid provides a simple API with optimal implementation of this feature.