ASP.NET
allows the following sources of data to be accessed and used:
1.
Databases (e.g., Access,
SQL Server, Oracle, MySQL)
2.
XML documents
3.
Business Objects
4.
Flat files
ASP.NET
hides the complex processes of data access and provides much higher level of
classes and objects through which data is accessed easily. These classes hide
all complex coding for connection, data retrieving, data querying, and data
manipulation.
ADO.NET
is the technology that provides the bridge between various ASP.NET control
objects and the backend data source. In this tutorial, we will look at data
access and working with the data in brief.
Retrieve and display data
It takes
two types of data controls to retrieve and display data in ASP.NET:
·
A data source control -
It manages the connection to the data, selection of data, and other jobs such
as paging and caching of data etc.
·
A data view control -
It binds and displays the data and allows data manipulation.
We will
discuss the data binding and data source controls in detail later. In this
section, we will use a SqlDataSource control to access data and a GridView
control to display and manipulate data in this chapter.
We will
also use an Access database, which contains the details about .Net books
available in the market. Name of our database is ASPDotNetStepByStep.mdb and we
will use the data table DotNetReferences.
The table
has the following columns: ID, Title, AuthorFirstName, AuthorLastName, Topic,
and Publisher.
Here is a
snapshot of the data table:
Let us
directly move to action, take the following steps:
(1) Create
a web site and add a SqlDataSourceControl on the web form.
(2) Click
on the Configure Data Source option.
(3) Click
on the New Connection button to establish connection with a database.
(4) Once
the connection is set up, you may save it for further use. At the next step,
you are asked to configure the select statement:
(5) Select
the columns and click next to complete the steps. Observe the WHERE, ORDER BY,
and the Advanced buttons. These buttons allow you to provide the where clause,
order by clause, and specify the insert, update, and delete commands of SQL
respectively. This way, you can manipulate the data.
(6) Add
a GridView control on the form. Choose the data source and format the control
using AutoFormat option.
(7) After
this the formatted GridView control displays the column headings, and the
application is ready to execute.
(8) Finally
execute the application.
The
content file code is as given:
<%@ Page Language="C#" AutoEventWireup="true"
CodeBehind="dataaccess.aspx.cs"
Inherits="datacaching.WebForm1" %>
<!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
runat="server">
<title>
Untitled Page
</title>
</head>
<body>
<form
id="form1" runat="server">
<div>
<asp:SqlDataSource ID="SqlDataSource1"
runat="server"
ConnectionString= "<%$
ConnectionStrings:ASPDotNetStepByStepConnectionString%>"
ProviderName=
"<%$ ConnectionStrings:
ASPDotNetStepByStepConnectionString.ProviderName
%>"
SelectCommand="SELECT [Title], [AuthorLastName],
[AuthorFirstName], [Topic] FROM [DotNetReferences]">
</asp:SqlDataSource>
<asp:GridView
ID="GridView1" runat="server"
AutoGenerateColumns="False" CellPadding="4"
DataSourceID="SqlDataSource1" ForeColor="#333333"
GridLines="None">
<RowStyle
BackColor="#F7F6F3" ForeColor="#333333" />
<Columns>
<asp:BoundField DataField="Title"
HeaderText="Title"
SortExpression="Title" />
<asp:BoundField DataField="AuthorLastName"
HeaderText="AuthorLastName"
SortExpression="AuthorLastName" />
<asp:BoundField DataField="AuthorFirstName"
HeaderText="AuthorFirstName"
SortExpression="AuthorFirstName" />
<asp:BoundField DataField="Topic"
HeaderText="Topic" SortExpression="Topic" />
</Columns>
<FooterStyle
BackColor="#5D7B9D"
Font-Bold="True" ForeColor="White" />
<PagerStyle
BackColor="#284775"
ForeColor="White" HorizontalAlign="Center" />
<SelectedRowStyle BackColor="#E2DED6"
Font-Bold="True" ForeColor="#333333" />
<HeaderStyle
BackColor="#5D7B9D" Font-Bold="True"
ForeColor="White" />
<EditRowStyle
BackColor="#999999" />
<AlternatingRowStyle BackColor="White"
ForeColor="#284775" />
</asp:GridView>
</div>
</form>
</body>
</html>
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