源代码：13033480群共享
一、try…catch…finally结构
using System;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;
using System.Collections.Generic;
using WestGarden.Model;
namespace WestGarden.Web
{
public partial class Default1 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
IList<CategoryInfo> catogories = new List<CategoryInfo>();
string connectionString = ConfigurationManager.ConnectionStrings["NetShopConnString"].ConnectionString;
string cmdText = "SELECT * FROM Category";
SqlCommand cmd = new SqlCommand();
SqlConnection conn = new SqlConnection(connectionString);
try
{
cmd.Connection = conn;
cmd.CommandType = CommandType.Text;
cmd.CommandText = cmdText;
conn.Open();
SqlDataReader rdr = cmd.ExecuteReader();
while (rdr.Read())
{
CategoryInfo category = new CategoryInfo(rdr.GetString(0), rdr.GetString(1), rdr.GetString(2));
catogories.Add(category);
}
rdr.Close();
}
finally
{
conn.Close();
}
ddlCategories.DataSource = catogories;
ddlCategories.DataTextField = "Name";
ddlCategories.DataValueField = "CategoryId";
ddlCategories.DataBind();
}
}
}
二、using()结构
using System;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;
using System.Collections.Generic;
using WestGarden.Model;
namespace WestGarden.Web
{
public partial class Default2 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
IList<CategoryInfo> catogories = new List<CategoryInfo>();
string connectionString = ConfigurationManager.ConnectionStrings["NetShopConnString"].ConnectionString;
string cmdText = "SELECT * FROM Category";
SqlCommand cmd = new SqlCommand();
//简单地说，using()结构等同于前面的try...finally结构，隐式关闭了conn。
using(SqlConnection conn = new SqlConnection(connectionString))
{
cmd.Connection = conn;
cmd.CommandType = CommandType.Text;
cmd.CommandText = cmdText;
conn.Open();
SqlDataReader rdr = cmd.ExecuteReader();
while (rdr.Read())
{
CategoryInfo category = new CategoryInfo(rdr.GetString(0), rdr.GetString(1), rdr.GetString(2));
catogories.Add(category);
}
rdr.Close();
}
ddlCategories.DataSource = catogories;
ddlCategories.DataTextField = "Name";
ddlCategories.DataValueField = "CategoryId";
ddlCategories.DataBind();
}
}
}
三、通用的数据库访问函数
using System;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;
using System.Collections.Generic;
using WestGarden.Model;
namespace WestGarden.Web
{
public partial class Default3 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
IList<CategoryInfo> catogories = new List<CategoryInfo>();
string connectionString = ConfigurationManager.ConnectionStrings["NetShopConnString"].ConnectionString;
string cmdText = "SELECT * FROM Category";
SqlDataReader rdr = ExecuteReader(connectionString, CommandType.Text, cmdText);
while (rdr.Read())
{
CategoryInfo category = new CategoryInfo(rdr.GetString(0), rdr.GetString(1), rdr.GetString(2));
catogories.Add(category);
}
rdr.Close();
ddlCategories.DataSource = catogories;
ddlCategories.DataTextField = "Name";
ddlCategories.DataValueField = "CategoryId";
ddlCategories.DataBind();
}
public static SqlDataReader ExecuteReader(string connectionString, CommandType cmdType, string cmdText)
{
SqlCommand cmd = new SqlCommand();
SqlConnection conn = new SqlConnection(connectionString);
try
{
cmd.Connection = conn;
cmd.CommandType = cmdType;
cmd.CommandText = cmdText;
conn.Open();
//如果创建了 SqlDataReader 并将 CommandBehavior 设置为 CloseConnection，
//则关闭 SqlDataReader 会自动关闭此连接
SqlDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
return rdr;
}
catch
{
conn.Close();
throw;
}
//finally
//{
// conn.Close();
//}
}
}
}
四、完善一下通用数据库访问函数
using System;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;
using System.Collections.Generic;
using WestGarden.Model;
namespace WestGarden.Web
{
public partial class Default4 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
IList<CategoryInfo> catogories = new List<CategoryInfo>();
string connectionString = ConfigurationManager.ConnectionStrings["NetShopConnString"].ConnectionString;
string cmdText = "SELECT * FROM Category";
SqlDataReader rdr = ExecuteReader(connectionString, CommandType.Text, cmdText,null);
while (rdr.Read())
{
CategoryInfo category = new CategoryInfo(rdr.GetString(0), rdr.GetString(1), rdr.GetString(2));
catogories.Add(category);
}
rdr.Close();
ddlCategories.DataSource = catogories;
ddlCategories.DataTextField = "Name";
ddlCategories.DataValueField = "CategoryId";
ddlCategories.DataBind();
}
public static SqlDataReader ExecuteReader(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
{
SqlCommand cmd = new SqlCommand();
SqlConnection conn = new SqlConnection(connectionString);
try
{
//cmd.Connection = conn;
//cmd.CommandType = cmdType;
//cmd.CommandText = cmdText;
//conn.Open();
PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
//如果创建了 SqlDataReader 并将 CommandBehavior 设置为 CloseConnection，
//则关闭 SqlDataReader 会自动关闭此连接。
SqlDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
cmd.Parameters.Clear();
return rdr;
}
catch
{
conn.Close();
throw;
}
//finally
//{
// conn.Close();
//}
}
private static void PrepareCommand(SqlCommand cmd, SqlConnection conn, SqlTransaction trans, CommandType cmdType, string cmdText, SqlParameter[] cmdParms)
{
if (conn.State != ConnectionState.Open)
conn.Open();
cmd.Connection = conn;
cmd.CommandText = cmdText;
if (trans != null)
cmd.Transaction = trans;
cmd.CommandType = cmdType;
if (cmdParms != null)
{
foreach (SqlParameter parm in cmdParms)
cmd.Parameters.Add(parm);
}
}
}
}
五、使用Reapter显示分类名称
1、窗体代码：
<asp:Repeater ID="repCategories" runat="server">
<HeaderTemplate>
<table cellspacing="0" border="0" style="border-collapse: collapse;">
</HeaderTemplate>
<ItemTemplate>
<tr>
<td>
<asp:HyperLink runat="server" ID="lnkCategory" NavigateUrl='<%# string.Format("~/Items.aspx?page=0&categoryId={0}", Eval("CategoryId")) %>'
Text='<%# Eval("Name") %>' /><asp:HiddenField runat="server" ID="hidCategoryId" Value='<%# Eval("CategoryId") %>' />
</td>
</tr>
</ItemTemplate>
<FooterTemplate>
</table>
</FooterTemplate>
</asp:Repeater>
2、代码页绑定代码：
repCategories.DataSource = catogories; repCategories.DataBind();