官术网_书友最值得收藏!

Sample Project using Code-Behind

Here is an example of the same guestbook application being coded using code-behind classes:

using System;
using System.Data;
using System.Data.OleDb;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
namespace Chapter2.CodeBehindStyle
{
public partial class Default : System.Web.UI.Page
{
protected void btnComments_Click(object sender, EventArgs e)
{
LoadComments();
}
/// <summary>
/// Load all comments from the Access DB
/// </summary>
private void LoadComments()
{
string AppPath = System.AppDomain.CurrentDomain. BaseDirectory.ToString();
string sCon = @"Provider=Microsoft.JET.OLEDB.4.0; Data Source=" + AppPath + "/App_Data/Guestbook.mdb";
using (OleDbConnection cn = new OleDbConnection(sCon))
{
string sQuery = @"SELECT * FROM Guestbook order by EntryDate desc";
OleDbCommand cmd = new OleDbCommand(sQuery, cn);
OleDbDataAdapter da = new OleDbDataAdapter(cmd);
DataSet ds = new DataSet();
cn.Open();
da.Fill(ds);
rptComments.DataSource = ds;
rptComments.DataBind();
}
}
}//end class
}//end namespace

In the code above we are simply loading all guestbook entries in the LoadComments() method and binding it to a repeater (rptComments) in the code-behind partial class file.

Here is the ASPX form:

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="Chapter2.CodeBehindStyle.Default" %>
<html>
<head>
<title>Chapter 2: Code-behind sample in ASP.NET</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:Button ID="btnComments" runat="server" Text="View All Comments" OnClick="btnComments_Click" />
<h1>Guestbook Entries</h1>
<asp:Repeater id="rptComments" runat="server">
<ItemTemplate>
Name: <%# Eval("FullName")%>
<br>
Email: <%# Eval("EmailID")%>
<br>
Website: <%# Eval("Website")%>
<br>
Dated: <%# Eval("EntryDate")%>
<br>
Comments: <%# Eval("Comments")%>
</ItemTemplate>
</asp:Repeater>
</div>
</form>
</body>
</html>

As you can see, we don't have any C# or VB.NET coding in the ASPX pages; all of the managed code is in the code-behind class. Also note that the declaration of any server side control is put in a separate designer.cs file, which is auto-generated after parsing the ASPX markup file. So we have a clean logical separation of the declarative ASPX controls placement (HTML part) and the actual managed code in the code-behind partial classes. Here is a diagrammatic representation of this 1-tier 1-layer style having 2 sub-layers in the main UI layer:

UI Layer

Sample Project using Code-Behind

From the given diagram, we can see that we still have one single physical DLL, but the UI code itself is logically separated into two layers—one in the markup code and the other in the code-behind file. Note that, as explained in the beginning of this chapter, this architecture is 1-tier from the application's viewpoint, but overall it is still 3-tier if we consider the client browser as the presentation tier, and the database as the data tier. We are only focusing on the application tier, which houses the UI layer in the above examples.

主站蜘蛛池模板: 三穗县| 通州区| 玉树县| 兴安盟| 瑞金市| 石台县| 九台市| 波密县| 城步| 施秉县| 十堰市| 北宁市| 黔东| 永兴县| 自贡市| 屯昌县| 淮北市| 中超| 泸州市| 甘肃省| 绵阳市| 延庆县| 南平市| 隆德县| 霍邱县| 比如县| 辽中县| 柘荣县| 涟水县| 屏东县| 桂东县| 武夷山市| 峨眉山市| 左云县| 乡城县| 卢氏县| 宁南县| 泌阳县| 明溪县| 沁源县| 灵武市|