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ASP.NET三层架构如何实现多条件检索？完整示例及代码解析详解

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2026-01-08
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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(); } }