ASP.NET.in.a.Nutshell.Second.Edition [Electronic resources]

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 columnsonly 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 ;
}

Hierarchy

System.Object System.Web.UI.Control(System.ComponentModel.IComponent, System.IDisposable, System.Web.UI.IParserAccessor, System.Web.UI.IDataBindingsAccessor) WebControl(System.Web.UI.IAttributeAccessor) BaseDataList DataGrid(System.Web.UI.INamingContainer)

Returned By

DataGridColumn.Owner

Passed To

DataGridColumnCollection.DataGridColumnCollection( )