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.
Imports System
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 'SimpleSpreadsheetControl
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 'New
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 'RenderContents
End Class 'SimpleSpreadsheetRow
End Namespace
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>");
}
}
}
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.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 >
<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>
<%@ 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 >
<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>