IDataItemContainer Interface
Definition
Important
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Enables data-bound control containers to identify a data item object for simplified data-binding operations.
public interface class IDataItemContainer : System::Web::UI::INamingContainerpublic interface IDataItemContainer : System.Web.UI.INamingContainertype IDataItemContainer = interface
interface INamingContainerPublic Interface IDataItemContainer
Implements INamingContainer- Derived
- Implements
Examples
The following code example demonstrates how to use the IDataItemContainer interface. The SimpleSpreadsheetControl is a control that displays tabular-style data, similar to a DataGrid or GridView control. It contains a set of SimpleSpreadsheetRow objects.
The SimpleSpreadsheetRow class is a container class that implements the IDataItemContainer interface. Although in this example the data item property is intuitively named Data, the DataItem property can be implemented to map to any property or return value of a method.
using System;
using System.Collections;
using System.Data.Common;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace Samples.AspNet.CS
{
public class SimpleSpreadsheetControl : CompositeDataBoundControl
{
protected Table table = new Table();
public virtual TableRowCollection Rows
{
get
{
return table.Rows;
}
}
protected override int CreateChildControls(IEnumerable dataSource, bool dataBinding)
{
int count = 0;
// If dataSource is not null, iterate through it and
// extract each element from it as a row, then
// create a SimpleSpreadsheetRow and add it to the
// rows collection.
if (dataSource != null)
{
SimpleSpreadsheetRow row;
IEnumerator e = dataSource.GetEnumerator();
while (e.MoveNext())
{
object datarow = e.Current;
row = new SimpleSpreadsheetRow(count, datarow);
this.Rows.Add(row);
++count;
}
Controls.Add(table);
}
return count;
}
}
//
//
public class SimpleSpreadsheetRow : TableRow, IDataItemContainer
{
private object data;
private int _itemIndex;
public SimpleSpreadsheetRow(int itemIndex, object o)
{
data = o;
_itemIndex = itemIndex;
}
public virtual object Data
{
get
{
return data;
}
}
object IDataItemContainer.DataItem
{
get
{
return Data;
}
}
int IDataItemContainer.DataItemIndex
{
get
{
return _itemIndex;
}
}
int IDataItemContainer.DisplayIndex
{
get
{
return _itemIndex;
}
}
protected override void RenderContents(HtmlTextWriter writer)
{
if (Data != null)
{
if (Data is System.Data.Common.DbDataRecord)
{
DbDataRecord temp = (DbDataRecord)Data;
for (int i = 0; i < temp.FieldCount; ++i)
{
writer.Write("<TD>");
writer.Write(temp.GetValue(i).ToString());
writer.Write("</TD>");
}
}
else
{
writer.Write("<TD>" + Data.ToString() + "</TD>");
}
}
else
{
writer.Write("<TD>This is a test</TD>");
}
}
}
}
Imports System.Collections
Imports System.Data.Common
Imports System.Web.UI
Imports System.Web.UI.WebControls
Namespace Samples.AspNet.VB
Public Class SimpleSpreadsheetControl
Inherits CompositeDataBoundControl
Protected table As New Table()
Public Overridable ReadOnly Property Rows() As TableRowCollection
Get
Return table.Rows
End Get
End Property
Protected Overrides Function CreateChildControls(ByVal dataSource As IEnumerable, ByVal dataBinding As Boolean) As Integer
Dim count As Integer = 0
' If dataSource is not Nothing, iterate through it and
' extract each element from it as a row, then
' create a SimpleSpreadsheetRow and add it to the
' rows collection.
If Not (dataSource Is Nothing) Then
Dim row As SimpleSpreadsheetRow
Dim e As IEnumerator = dataSource.GetEnumerator()
While e.MoveNext()
Dim datarow As Object = e.Current
row = New SimpleSpreadsheetRow(count, datarow)
Me.Rows.Add(row)
count += 1
End While
Controls.Add(table)
End If
Return count
End Function 'CreateChildControls
End Class
Public Class SimpleSpreadsheetRow
Inherits TableRow
Implements IDataItemContainer
Private dataObj As Object
Private _itemIndex As Integer
Public Sub New(ByVal itemIndex As Integer, ByVal o As Object)
dataObj = o
_itemIndex = itemIndex
End Sub
Public Overridable ReadOnly Property Data() As Object
Get
Return dataObj
End Get
End Property
ReadOnly Property DataItem() As Object Implements IDataItemContainer.DataItem
Get
Return Data
End Get
End Property
ReadOnly Property DataItemIndex() As Integer Implements IDataItemContainer.DataItemIndex
Get
Return _itemIndex
End Get
End Property
ReadOnly Property DisplayIndex() As Integer Implements IDataItemContainer.DisplayIndex
Get
Return _itemIndex
End Get
End Property
Protected Overrides Sub RenderContents(ByVal writer As HtmlTextWriter)
If Not (Data Is Nothing) Then
If TypeOf Data Is System.Data.Common.DbDataRecord Then
Dim temp As DbDataRecord = CType(Data, DbDataRecord)
Dim i As Integer
While i < temp.FieldCount
writer.Write("<TD>")
writer.Write(temp.GetValue(i).ToString())
writer.Write("</TD>")
i += 1
End While
Else
writer.Write(("<TD>" + Data.ToString() + "</TD>"))
End If
Else
writer.Write("<TD>This is a test</TD>")
End If
End Sub
End Class
End Namespace
The following code example demonstrates how to use the SimpleSpreadsheetControl and AccessDataSource control to display data in an Access database.
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.CS"
Assembly="Samples.AspNet.CS" %>
<%@ Page language="c#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>IDataItemContainer - C# Example</title>
</head>
<body>
<form id="Form1" method="post" runat="server">
<aspSample:SimpleSpreadsheetControl
id="SimpleSpreadsheet1"
runat="server"
datasourceid="AccessDataSource1" />
<asp:accessdatasource
id="AccessDataSource1"
runat="server"
datasourcemode="DataReader"
datafile="Northwind.mdb"
SelectCommand="SELECT OrderID,CustomerID,OrderDate,RequiredDate,
ShippedDate FROM Orders WHERE EmployeeID = (SELECT EmployeeID
FROM Employees WHERE LastName = 'King')">
</asp:accessdatasource>
</form>
</body>
</html>
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.VB"
Assembly="Samples.AspNet.VB" %>
<%@ Page language="vb" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>IDataItemContainer - VB Example</title>
</head>
<body>
<form id="Form1" method="post" runat="server">
<aspSample:SimpleSpreadsheetControl
id="SimpleSpreadsheet1"
runat="server"
datasourceid="AccessDataSource1" />
<asp:accessdatasource
id="AccessDataSource1"
runat="server"
datasourcemode="DataReader"
datafile="Northwind.mdb"
SelectCommand="SELECT OrderID,CustomerID,OrderDate,RequiredDate,ShippedDate
FROM Orders WHERE EmployeeID =
(SELECT EmployeeID FROM Employees WHERE LastName = 'King')">
</asp:accessdatasource>
</form>
</body>
</html>
Remarks
Container classes that implement the IDataItemContainer interface can specify which of their properties identifies the data item for data-binding operations, such as late binding with the DataBinder class.
Properties
| DataItem |
When implemented, gets an |
| DataItemIndex |
When implemented, gets the index of the data item bound to a control. |
| DisplayIndex |
When implemented, gets the position of the data item as displayed in a control. |
Extension Methods
| GetDefaultValues(INamingContainer) |
Gets the collection of the default values for the specified data control. |
| GetMetaTable(INamingContainer) |
Gets the table metadata for the specified data control. |
| SetMetaTable(INamingContainer, MetaTable, IDictionary<String,Object>) |
Sets the table metadata and default value mapping for the specified data control. |
| SetMetaTable(INamingContainer, MetaTable, Object) |
Sets the table metadata and default value mapping for the specified data control. |
| SetMetaTable(INamingContainer, MetaTable) |
Sets the table metadata for the specified data control. |
| TryGetMetaTable(INamingContainer, MetaTable) |
Determines whether table metadata is available. |
| EnableDynamicData(INamingContainer, Type, IDictionary<String,Object>) |
Enables Dynamic Data behavior for the specified data control. |
| EnableDynamicData(INamingContainer, Type, Object) |
Enables Dynamic Data behavior for the specified data control. |
| EnableDynamicData(INamingContainer, Type) |
Enables Dynamic Data behavior for the specified data control. |
