C# DataTable DataSet DataRow 转实体类集合，实体类和实体类集合转成DataTable 扩展方法分享

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C# DataTable  DataSet  DataRow 转实体类集合，实体类和实体类集合转成DataTable 扩展方法分享

using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Reflection;

namespace System
{
    /// <summary>
    /// DataTable转list泛型集合    
    /// </summary>
    public static class DataTableExtend
    {
        /// <summary>
        /// DataTable转换List
        /// </summary>
        /// <typeparam name="T">泛型</typeparam>
        /// <param name="dt">DataTable</param>
        /// <returns>List泛型集合</returns>
        public static List<T> ToList<T>(this DataTable dt) where T : class, new()
        {
            var list = new List<T>();
            foreach (DataRow dr in dt.Rows)
            {
                //泛型对象
                T model = dr.ToDataRowModel<T>();
                list.Add(model);
            }
            return list;
        }

        /// <summary>
        /// DataSet转换List
        /// </summary>
        /// <typeparam name="T">泛型</typeparam>
        /// <param name="dt">DataTable</param>
        /// <returns>List泛型集合</returns>
        public static List<T> ToList<T>(this DataSet ds) where T : class, new()
        {
            var list = new List<T>();
            list = ds.Tables[0].ToList<T>();
            return list;
        }

        /// <summary>
        /// DataRow转换T模型
        /// </summary>
        /// <typeparam name="T">泛型</typeparam>
        /// <param name="dt">DataTable</param>
        /// <returns>List泛型集合</returns>
        public static T ToDataRowModel<T>(this DataRow dr) where T : class, new()
        {
            //泛型对象
            T model = new T();
            //属性集合
            var listPro = model.GetType().GetProperties().Where(item => !item.IsDefined(typeof(InternalAttribute), false)).ToArray();
            foreach (PropertyInfo pi in listPro)
            {
                var columnName = pi.Name;//属性=字段
                var columnType = pi.PropertyType;//属性类型
                var underlyingtype = Nullable.GetUnderlyingType(columnType);//返回指定可以为null值的类型

                //判断属性是否可以写入
                if (!pi.CanWrite) continue;
                if (!dr.Table.Columns.Contains(columnName)) continue;
                var value = dr[columnName];
                //判断字段值是否为空
                if (value == DBNull.Value) continue;
                //根据属性类型转换数据库字段类型
                if (columnType == typeof(string))
                    pi.SetValue(model, value.ToString(), null);
                else if (columnType == typeof(int) || columnType == typeof(int?))
                    pi.SetValue(model, Convert.ToInt32(value), null);
                else if (columnType == typeof(DateTime) || columnType == typeof(DateTime?))
                    pi.SetValue(model, Convert.ToDateTime(value), null);
                else if (columnType == typeof(decimal))
                    pi.SetValue(model, Convert.ToDecimal(value), null);
                else if (columnType == typeof(double))
                    pi.SetValue(model, Convert.ToDouble(value), null);
                else if (columnType == typeof(float))
                    pi.SetValue(model, Convert.ToSingle(value), null);
                else if ((underlyingtype ?? columnType).IsEnum)
                {
                    if (underlyingtype != null && !string.IsNullOrEmpty(value.ToString()))
                        pi.SetValue(model, Enum.Parse(underlyingtype ?? columnType, value.ToString()), null);
                    else if (underlyingtype == null && !string.IsNullOrEmpty(value.ToString()))
                        pi.SetValue(model, Convert.ToInt32(value), null);
                    else
                        pi.SetValue(model, -1, null);
                }
                else
                    pi.SetValue(model, value, null);
            }
            return model;
        }
    }
}

 实体列表转换成DataTable

        /// <summary>
        ///     实体列表转换成DataTable
        /// </summary>
        /// <typeparam name="TEntity">实体</typeparam>
        /// <param name="entityList"> 实体列表</param>
        /// <returns></returns>
        public static DataTable EntityListToDataTable<TEntity>(this IList<TEntity> entityList)
            where TEntity : class
        {
            if (entityList == null) return null;
            var dt = new DataTable(typeof(TEntity).Name);

            var myPropertyInfo = typeof(TEntity).GetProperties(BindingFlags.Public | BindingFlags.Instance);

            #region 创建表结构

            foreach (var property in myPropertyInfo)
            {                
                Type colType = property.PropertyType;
                if (colType.IsGenericType && colType.GetGenericTypeDefinition() == typeof(Nullable<>))
                {
                    colType = colType.GetGenericArguments()[0];
                    var col = new DataColumn(property.Name, colType) { Caption = property.ToDescription() };
                    col.AllowDBNull = true;
                    dt.Columns.Add(col);
                }
                else
                {
                    var col = new DataColumn(property.Name, colType) { Caption = property.ToDescription() };
                    dt.Columns.Add(col);
                }
                   
            }

            #endregion

            foreach (var entity in entityList)
            {
                if (entity == null) continue;

                var row = dt.NewRow();
                foreach (var propertyInfo in myPropertyInfo)
                {
                    if (propertyInfo.GetValue(entity, null) == null)
                        row[propertyInfo.Name] = DBNull.Value;
                    else
                        row[propertyInfo.Name] = propertyInfo.GetValue(entity, null);
                }

                dt.Rows.Add(row);
            }

            return dt;
        }

实体转换成DataTable

        /// <summary>
        ///     实体转换成DataTable
        ///     Add by loki 20201011
        /// </summary>
        /// <typeparam name="TEntity">实体</typeparam>
        /// <returns></returns>
        public static DataTable EntityToDataTable<TEntity>(this TEntity entity)
            where TEntity : class
        {
            if (entity == null) return null;
            var dt = new DataTable(typeof(TEntity).Name);

            var myPropertyInfo = typeof(TEntity).GetProperties(BindingFlags.Public | BindingFlags.Instance);

            #region 创建表结构

            foreach (var property in myPropertyInfo)
            {                
                Type colType = property.PropertyType;
                if (colType.IsGenericType && colType.GetGenericTypeDefinition() == typeof(Nullable<>))
                {
                    colType = colType.GetGenericArguments()[0];
                    var col = new DataColumn(property.Name, colType) { Caption = property.ToDescription() };
                    col.AllowDBNull = true;
                    dt.Columns.Add(col);
                }
                else
                {
                    var col = new DataColumn(property.Name, colType) { Caption = property.ToDescription() };
                    dt.Columns.Add(col);
                }

            }

            #endregion
            var row = dt.NewRow();
            foreach (var propertyInfo in myPropertyInfo)
            {
                if (propertyInfo.GetValue(entity, null) == null)
                    row[propertyInfo.Name] = DBNull.Value;
                else
                    row[propertyInfo.Name] = propertyInfo.GetValue(entity, null);
            }

            dt.Rows.Add(row);

            return dt;
        }

你如果觉得有用就拿去不用谢！C# DataTable  DataSet  DataRow 转实体类集合，实体类和实体类集合转成DataTable 扩展方法分享，这里其实很简单，就是用到反射技术去实现的，将数据库表字段与C#实体属性进行反射