Dapper分页查询常用写法

1、首先写基本查询和查询参数语句如下：

using Dapper;
using Microsoft.EntityFrameworkCore.Storage.ValueConversion.Internal;
using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Tzkj.Dapper;
using Tzkj.DigitalSuite.Commodity.Query;
using Tzkj.Superhard.SupplyDemand.EntityFrameworkCore;
using Tzkj.Superhard.SupplyDemand.Query.Supplies;
using Tzkj.Superhard.SupplyDemand.SupplyDemands;
using Volo.Abp.DependencyInjection;
using Volo.Abp.EntityFrameworkCore;

namespace Tzkj.Superhard.SupplyDemand.Query.Demands
{
    /// 

    /// 需求dapper仓储
    /// 
    public class DemandDapperRepository : SupdServiceDapperRepositoryBase, ITransientDependency
    {
        /// 

        /// 构造函数
        /// 
        /// 
        public DemandDapperRepository(IDbContextProvider dbContextProvider) : base(dbContextProvider)
        {

        }

        /// 

        /// 获取需求服务分页列表
        /// 
        /// 
        /// 
        /// 
        public async Task> GetPagedResultAsync(Guid userId, string? name, string? status,
             int pageIndex, int pageSize)
        {
            const string tableJoinStr = "supd_demand_info";
            const string columnsStr = " id,category,title,contact_person,contact_number,publish_time,registration_deadline,status";
            const string orderByStr = "publish_time desc";
            var whereStr = "1=1 and del_flag=0 and create_by=@userId";
            var sqlPredicate = new List();
            var queryParams = new DynamicParameters();

            queryParams.Add(nameof(userId), userId, DbType.Guid);
            if (!name.IsNullOrWhiteSpace())
            {
                sqlPredicate.Add("title like @name");
                queryParams.Add(nameof(name), $"%{name}%", DbType.String);
            }
            if (!status.IsNullOrWhiteSpace())
            {
                sqlPredicate.Add("status = @status");
                queryParams.Add(nameof(status), status, DbType.String);
            }

            return await GetPagedResultAsync(tableJoinStr, columnsStr, whereStr, orderByStr, pageIndex, pageSize, queryParams);
        }
    }
}

2、创建SupdServiceDapperRepositoryBase基类，在上方代码中会被继承

using Dapper;
using System;
using System.Collections.Generic;
using System.Data;
using System.Diagnostics.Tracing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Tzkj.Dapper;
using Tzkj.Superhard.SupplyDemand.EntityFrameworkCore;
using Volo.Abp;
using Volo.Abp.DependencyInjection;
using Volo.Abp.Domain.Repositories.Dapper;
using Volo.Abp.EntityFrameworkCore;
namespace Tzkj.DigitalSuite.Commodity.Query
{
public class SupdServiceDapperRepositoryBase : DapperRepository
{
    /// 

    /// 
    /// 
    /// 
    /// 
    /// 
    /// 
    /// 
    /// 
    /// 
    /// 
    /// 
    /// 
    protected async Task> GetPagedResultAsync(
        string tablesJoinStr,
        string columnsStr,
        string whereStr,
        string orderByStr,
        int pageIndex,
        int pageSize,
        DynamicParameters queryParams = null)
    {
        if (pageIndex <= 0 || pageSize <= 0)
        {
            //throw new ArgumentException("pageIndex与pageSize 不可以小于或等于0");
            throw new UserFriendlyException("pageIndex与pageSize 不可以小于或等于0");
        }
        var skip = (pageIndex - 1) * pageSize;
        var sb = new StringBuilder();
        sb.AppendFormat("SELECT COUNT(1) FROM {0} where {1};", tablesJoinStr, whereStr);
        sb.AppendFormat(@"SELECT {0}
                            FROM {1}
                            WHERE {2}
                            ORDER BY {3}
                            LIMIT @skip,@take", columnsStr, tablesJoinStr, whereStr, orderByStr);

        queryParams ??= new DynamicParameters();
        queryParams.Add("skip", skip, DbType.Int32);
        queryParams.Add("take", pageSize, DbType.Int32);
        var connection = await GetDbConnectionAsync();
        var dbTransaction = await GetDbTransactionAsync();
        using var reader = await connection.QueryMultipleAsync(sb.ToString(), queryParams, transaction: dbTransaction);
        //using var reader = await connection.QueryMultipleAsync(sb.ToString(), queryParams);
        var total = await reader.ReadFirstAsync();
        var list = await reader.ReadAsync();
        return new PagedResultQto(total, list.ToList());
    }

    protected string GetQuerySql(string noWhereSql, List sqlPredicates)
    {
        if (!sqlPredicates.Any()) return noWhereSql;
        var sqlPredicatesStr = sqlPredicates.Aggregate((p, n) => $"{p} and {n}");
        var sql = @$"{noWhereSql}
                 where {sqlPredicatesStr}";
        return sql;
    }
}