The DataGrid control is, at its simplest, a
data-bound list displayed in a table grid structure. It provides a
rich set of functionality that makes it the most versatile data-bound
control, including support for selection, editing, deleting, paging,
and sorting.
Columns can be added to a DataGrid in two ways.
First, if the AutoGenerateColumns property is
True, a BoundColumn will be
created for every column in the data source specified by
DataSource. Alternatively, you can define columns
by adding nested tags in the .aspx file. (If you
mix both approaches, the automatically generated columns will always
be added last.) Columns can be BoundColumn,
ButtonColumn,
EditCommandColumn,
HyperLinkColumn, or
TemplateColumn controls (each of which are
described separately in this namespace). The order that the columns
appear is determined by the order the column tags are listed in the
.aspx, and you can manipulate them
programmatically through the Columns collection.
Note that this collection does not contain automatically generated
columns—only ones that have defined templates.
The DataGrid has a number of properties that allow
you to control its appearance. You can set
TableItemStyle objects for various properties,
including footers, headers (used automatically for column titles),
and items. (The corresponding DataGrid properties
end with the word "Style.") You can
also use the ShowHeader and
ShowFooter properties to configure whether headers
and footers will be displayed.
To allow row selection for DataGrid, set the
SelectedItemTemplate to look different than the ItemTemplate. Then
add a button column that allows selection (for example, you might use
the text "Select") and set the
SelectedIndex property to the appropriate row in
the ItemCommand event handler. To allow in-place
editing, add an EditCommandColumn column and set
the EditItemIndex (then rebind to the data source)
in the EditCommand event handler. Any properties
that are not marked as read-only in the template will be editable
through automatically provided text boxes. You can handle the
UpdateCommand event to commit the actual change.
To disable editing or selection for a DataGrid,
set the EditItemIndex or
SelectedIndex to -1.
To provide sorting, enable the AllowSorting
property and rebind the appropriate sorted data in response to the
SortCommand event. Finally, to provide paging,
enable the AllowPaging property and set a number
of rows in the PageSize property. When the
PageIndexChanged event is triggered, set the
CurrentPageIndex to the appropriate page. Note
that automatic paging causes the complete data table to be retrieved,
even though only a few rows are being displayed. To optimize
performance, you should enable the
AllowCustomPaging property and provide custom data
access code in the CurrentPageIndex event handler.
When using custom paging, you must also set the
VirtualItemCount property to the total number of
records to allow the DataGrid to determine the
total number of pages needed.
public class DataGrid : BaseDataList, System.Web.UI.INamingContainer {
// Public Constructors
public DataGrid( );
// Public Static Fields
public const string CancelCommandName; // =Cancel
public const string DeleteCommandName; // =Delete
public const string EditCommandName; // =Edit
public const string NextPageCommandArgument; // =Next
public const string PageCommandName; // =Page
public const string PrevPageCommandArgument; // =Prev
public const string SelectCommandName; // =Select
public const string SortCommandName; // =Sort
public const string UpdateCommandName; // =Update
// Public Instance Properties
public virtual bool AllowCustomPaging{set; get; }
public virtual bool AllowPaging{set; get; }
public virtual bool AllowSorting{set; get; }
public virtual TableItemStyle AlternatingItemStyle{get; }
public virtual bool AutoGenerateColumns{set; get; }
public virtual string BackImageUrl{set; get; }
public virtual DataGridColumnCollection Columns{get; }
public int CurrentPageIndex{set; get; }
public virtual int EditItemIndex{set; get; }
public virtual TableItemStyle EditItemStyle{get; }
public virtual TableItemStyle FooterStyle{get; }
public virtual TableItemStyle HeaderStyle{get; }
public virtual DataGridItemCollection Items{get; }
public virtual TableItemStyle ItemStyle{get; }
public int PageCount{get; }
public virtual DataGridPagerStyle PagerStyle{get; }
public virtual int PageSize{set; get; }
public virtual int SelectedIndex{set; get; }
public virtual DataGridItem SelectedItem{get; }
public virtual TableItemStyle SelectedItemStyle{get; }
public virtual bool ShowFooter{set; get; }
public virtual bool ShowHeader{set; get; }
public virtual int VirtualItemCount{set; get; }
// Protected Instance Methods
protected virtual ArrayList CreateColumnSet(PagedDataSource dataSource, bool useDataSource);
protected override void CreateControlHierarchy(bool useDataSource); // overrides BaseDataList
protected override Style CreateControlStyle( ); // overrides WebControl
protected virtual DataGridItem CreateItem(int itemIndex, int dataSourceIndex, ListItemType itemType);
protected virtual void InitializeItem(DataGridItem item, DataGridColumn[ ] columns);
protected virtual void InitializePager(DataGridItem item, int columnSpan, PagedDataSource pagedDataSource);
protected override void LoadViewState(object savedState); // overrides WebControl
protected override bool OnBubbleEvent(object source, EventArgs e);// overrides System.Web.UI.Control
protected virtual void OnCancelCommand(DataGridCommandEventArgs e);
protected virtual void OnDeleteCommand(DataGridCommandEventArgs e);
protected virtual void OnEditCommand(DataGridCommandEventArgs e);
protected virtual void OnItemCommand(DataGridCommandEventArgs e);
protected virtual void OnItemCreated(DataGridItemEventArgs e);
protected virtual void OnItemDataBound(DataGridItemEventArgs e);
protected virtual void OnPageIndexChanged(DataGridPageChangedEventArgs e);
protected virtual void OnSortCommand(DataGridSortCommandEventArgs e);
protected virtual void OnUpdateCommand(DataGridCommandEventArgs e);
protected override void PrepareControlHierarchy( ); // overrides BaseDataList
protected override object SaveViewState( ); // overrides WebControl
protected override void TrackViewState( );// overrides WebControl
// Events
public event DataGridCommandEventHandler CancelCommand;
public event DataGridCommandEventHandler DeleteCommand;
public event DataGridCommandEventHandler EditCommand;
public event DataGridCommandEventHandler ItemCommand;
public event DataGridItemEventHandler ItemCreated;
public event DataGridItemEventHandler ItemDataBound;
public event DataGridPageChangedEventHandler PageIndexChanged;
public event DataGridSortCommandEventHandler SortCommand;
public event DataGridCommandEventHandler UpdateCommand;
}
System.Web.UI.Control(System.ComponentModel.IComponent,
System.IDisposable,
System.Web.UI.IParserAccessor,
System.Web.UI.IDataBindingsAccessor)