A header is a collection of columns that enables displaying data in data grid's cells. A grid supports one or more headers. When a single header is used, the grid has TreeListView control behavior, just like the Microsoft Windows Explorer. Multiple headers enable separate column management for each hierarchical level. At a glance, every header consists of two panels: the grouping panel and the columns panel. These panels aren't related to each other. It means that the same column may be present in both panels simultaneously. Each column carries very important information about width, location, visibility, grouping and data sorting.

In programming, headers can be added to the grid by calling GridControl.Headers.Add(Header header) method. When a header is added to GridControl.Headers collection, a zero-based index is assigned to it in the hierarchy. When you call Header.Add(Column column) method, additional columns are added to a header. After that columns can be accessed with indexer operator. Every header has the following collections of columns:

• Header.VisibleColumns - List of visible columns
• Header.Columns - List of ALL columns
• Header.SortedColumns - List of columns, that participate in sorting
• Header.FixedColumns - List of non-scrollable columns
• Header.GroupedColumns - List of grouped columns

The same column can be located in different lists. Almost each of the aforementioned lists has Clear() method, that has a specific action when invoked on a certain collection. Specifically, Header.GroupedColumns.Clear() removes data grouping in header of a grid. To group data you only have to set Column.Grouped property to true. If you set this property to true for multiple columns, it will result in multiple grouping and will fill corresponding collection in the data grid header. Such approach can be used in sorting (Column.SortDirection). The number of fixed columns is defined by Header.FixedColumns.Count.

XAML code example:

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<df:GridControl x:Name="grid"> <df:GridControl.Headers> <!-- Top-level header --> <df:Header> <df:Header.Columns> <df:Column Id="FirstName" Title="First Name"/> <df:Column Id="LastName" Title="Last Name" /> </df:Header.Columns> </df:Header> <!-- Child header --> <df:Header> <df:Header.Columns> <df:Column Id="BookName" Title="Name" /> <df:Column Id="BookGenre" Title="Genre" /> </df:Header.Columns> </df:Header> </df:GridControl.Headers> </df:GridControl>

The same can be done in the C# code:

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public void MultipleHeaderGrid(GridControl grid) { //Initialize the grid with two headers grid.Headers.Add(new Header()); grid.Headers[0].Add(new Column("FirstName", "First Name")); grid.Headers[0].Add(new Column("LastName", "Last Name")); grid.Headers.Add(new Header()); grid.Headers[1].Add(new Column("BookName", "Name")); grid.Headers[1].Add(new Column("BookGenre", "Genre")); }