ASP.NET 三层架构多条件检索示例
实体层 (Entity Layer)
// User.cs
public class UserEntity
{
public int ID { get; set; }
public string UserName { get; set; }
public string Email { get; set; }
public bool Status { get; set; } // 状态: 启用/禁用
}
数据访问层 (DAL)
1 接口定义
// IUserDal.cs
public interface IUserDal
{
List<UserEntity> GetUserByConditions(
string userName,
string email,
bool? status,
int? pageSize,
int? pageNumber);
}
2 实现类
// UserDal.cs
public class UserDal : IUserDal
{
private readonly string _connectionString;
public UserDal(string connectionString)
{
_connectionString = connectionString;
}
public List<UserEntity> GetUserByConditions(
string userName,
string email,
bool? status,
int? pageSize,
int? pageNumber)
{
string sql = "SELECT * FROM Users WHERE 1=1";
List<SqlParameter> parameters = new List<SqlParameter>();
// 构建条件查询
if (!string.IsNullOrEmpty(userName))
{
sql += " AND UserName LIKE @UserName";
parameters.Add(new SqlParameter("@UserName", $"%{userName}%"));
}
if (!string.IsNullOrEmpty(email))
{
sql += " AND Email LIKE @Email";
parameters.Add(new SqlParameter("@Email", $"%{email}"));
}
if (status.HasValue)
{
sql += " AND Status = @Status";
parameters.Add(new SqlParameter("@Status", status.Value));
}
// 分页处理
if (pageSize.HasValue && pageNumber.HasValue)
{
sql += " ORDER BY ID OFFSET (@PageNumber - 1) * @PageSize ROWS FETCH NEXT @PageSize ROWS ONLY";
parameters.Add(new SqlParameter("@PageSize", pageSize.Value));
parameters.Add(new SqlParameter("@PageNumber", pageNumber.Value));
}
using (SqlConnection conn = new SqlConnection(_connectionString))
{
SqlCommand cmd = new SqlCommand(sql, conn);
cmd.Parameters.AddRange(parameters.ToArray());
using (SqlDataReader reader = cmd.ExecuteReader())
{
List<UserEntity> users = new List<UserEntity>();
while (reader.Read())
{
users.Add(new UserEntity
{
ID = reader.GetInt32(0),
UserName = reader.GetString(1),
Email = reader.GetString(2),
Status = reader.GetBoolean(3)
});
}
return users;
}
}
}
}
业务逻辑层 (BLL)
1 接口定义
// IUserBll.cs
public interface IUserBll
{
List<UserEntity> GetUserByConditions(
string userName,
string email,
bool? status,
int? pageSize,
int? pageNumber);
}
2 实现类
// UserBll.cs
public class UserBll : IUserBll
{
private readonly IUserDal _userDal;
public UserBll(IUserDal userDal)
{
_userDal = userDal;
}
public List<UserEntity> GetUserByConditions(
string userName,
string email,
bool? status,
int? pageSize,
int? pageNumber)
{
return _userDal.GetUserByConditions(userName, email, status, pageSize, pageNumber);
}
}
表示层 (ASPX页面)
1 页面布局
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Search.aspx.cs" Inherits="Search" %>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">多条件检索示例</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<h2>用户多条件检索</h2>
<div>
<asp:TextBox ID="txtUserName" runat="server" placeholder="用户名" />
<asp:TextBox ID="txtEmail" runat="server" placeholder="邮箱" />
<asp:CheckBox ID="chkStatus" runat="server" Text="启用" Checked="true" />
<asp:Button ID="btnSearch" runat="server" Text="搜索" OnClick="btnSearch_Click" />
</div>
<asp:GridView ID="gvUsers" runat="server"
AutoGenerateColumns="False"
AllowPaging="True"
OnPageIndexChanging="gvUsers_PageIndexChanging">
<Columns>
<asp:BoundField DataField="ID" HeaderText="ID" />
<asp:BoundField DataField="UserName" HeaderText="用户名" />
<asp:BoundField DataField="Email" HeaderText="邮箱" />
<asp:BoundField DataField="Status" HeaderText="状态" />
</Columns>
</asp:GridView>
</div>
</form>
</body>
</html>
2 代码隐藏文件
// Search.aspx.cs
public partial class Search : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
BindUsers();
}
}
protected void btnSearch_Click(object sender, EventArgs e)
{
BindUsers();
}
protected void BindUsers()
{
// 获取查询参数
string userName = txtUserName.Text.Trim();
string email = txtEmail.Text.Trim();
bool? status = chkStatus.Checked;
// 获取分页参数
int pageSize = 10; // 默认每页10条
int pageNumber = gvUsers.PageIndex + 1;
// 创建BLL实例
UserBll userBll = new UserBll(new UserDal(ConfigurationManager.ConnectionStrings["DefaultConnection"].ConnectionString));
// 调用BLL方法
List<UserEntity> users = userBll.GetUserByConditions(
userName,
email,
status,
pageSize,
pageNumber);
// 绑定数据
gvUsers.DataSource = users;
gvUsers.DataBind();
}
protected void gvUsers_PageIndexChanging(object sender, GridViewPageEventArgs e)
{
gvUsers.PageIndex = e.NewPageIndex;
BindUsers();
}
}
使用说明
-
数据库准备：
- 创建Users表,包含ID, UserName, Email, Status字段
- 插入测试数据
-
配置连接字符串：
在Web.config中添加数据库连接字符串
-
运行效果：
- 用户可以通过输入用户名、邮箱和状态来筛选
- 支持分页显示结果
-
关键特性：
- 三层架构分离关注点
- 参数化查询防止SQL注入
- 分页功能集成
- 响应式搜索逻辑
这个示例展示了如何使用三层架构实现灵活的多条件检索功能,同时保持代码的可维护性和扩展性。
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