C#中Datatable和List互相转换

　　其实早就该写的，哈哈，不过今天刚想起来注册，热热手，就写一下，哈哈。

　　直接上内容吧：

　　建立一个控制台应用程序，

            List<students> Studentlist =
            new List<students>{
                new students{ Name = "zhagnsan1", Chinese = 101, Math = 90, English = 80 },
                new students{ Name = "zhagnsan2", Chinese = 102, Math = 90, English = 80 },
                new students{ Name = "zhagnsan3", Chinese = 103, Math = 90, English = 80 }
            };
            DataTable dt = ListToDatatableHelper.ToDataTable(Studentlist);
            this.dataGridView1.DataSource = dt;

            List<students> list = DatatableToListHelper.ConvertToList(dt);

        　　public class students
        　　{
            public string Name { get; set; }
            public double English { get; set; }
            public double Chinese { get; set; }
            public double Math { get; set; }
        　　}

　　ListToDatatableHelper.cs中的内容为：

using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;

namespace ListToDatatable
{
    public class ListToDatatableHelper
    {
        /// <summary>
        /// Convert a List{T} to a DataTable.
        /// </summary>
        public static DataTable ToDataTable<T>(List<T> items)
        {
            var tb = new DataTable(typeof(T).Name);

            PropertyInfo[] props = typeof(T).GetProperties(BindingFlags.Public | BindingFlags.Instance);

            foreach (PropertyInfo prop in props)
            {
                Type t = GetCoreType(prop.PropertyType);
                tb.Columns.Add(prop.Name, t);
            }

            foreach (T item in items)
            {
                var values = new object[props.Length];

                for (int i = 0; i < props.Length; i++)
                {
                    values[i] = props[i].GetValue(item, null);
                }

                tb.Rows.Add(values);
            }

            return tb;
        }

        /// <summary>
        /// Determine of specified type is nullable
        /// </summary>
        public static bool IsNullable(Type t)
        {
            return !t.IsValueType || (t.IsGenericType && t.GetGenericTypeDefinition() == typeof(Nullable<>));
        }

        /// <summary>
        /// Return underlying type if type is Nullable otherwise return the type
        /// </summary>
        public static Type GetCoreType(Type t)
        {
            if (t != null && IsNullable(t))
            {
                if (!t.IsValueType)
                {
                    return t;
                }
                else
                {
                    return Nullable.GetUnderlyingType(t);
                }
            }
            else
            {
                return t;
            }
        }

        //*************************************************
        /// <summary>
        /// List转Datatable
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="table"></param>
        /// <returns></returns>
        public static IList<T> ConvertTo<T>(DataTable table)
        {
            if (table == null)
            {
                return null;
            }

            List<DataRow> rows = new List<DataRow>();

            foreach (DataRow row in table.Rows)
            {
                rows.Add(row);
            }

            return ConvertTo<T>(rows);
        }

        public static IList<T> ConvertTo<T>(IList<DataRow> rows)
        {
            IList<T> list = null;

            if (rows != null)
            {
                list = new List<T>();

                foreach (DataRow row in rows)
                {
                    T item = CreateItem<T>(row);
                    list.Add(item);
                }
            }

            return list;
        }

        public static T CreateItem<T>(DataRow row)
        {
            T obj = default(T);
            if (row != null)
            {
                obj = Activator.CreateInstance<T>();

                foreach (DataColumn column in row.Table.Columns)
                {
                    PropertyInfo prop = obj.GetType().GetProperty(column.ColumnName);
                    try
                    {
                        object value = row[column.ColumnName];
                        prop.SetValue(obj, value, null);
                    }
                    catch
                    {  //You can log something here     
                       //throw;    
                    }
                }
            }

            return obj;
        }
    }
}

 

　　DatatableToListHelper.cs中的内容为：

using NPOI.SS.Formula.Functions;
using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;
using static ListToDatatable.Form1;

namespace ListToDatatable
{
    class DatatableToListHelper
    {
        /// <summary>  
        /// 利用反射和泛型  
        /// </summary>  
        /// <param name="dt"></param>  
        /// <returns></returns>  
        public static List<students> ConvertToList(DataTable dt)
        {
            // 定义集合  
            List<students> ts = new List<students>();

            // 获得此模型的类型  
            Type type = typeof(students);
            //定义一个临时变量  
            string tempName = string.Empty;
            //遍历DataTable中所有的数据行  
            foreach (DataRow dr in dt.Rows)
            {
                students t = new students();
                // 获得此模型的公共属性  
                PropertyInfo[] propertys = t.GetType().GetProperties();
                //遍历该对象的所有属性  
                foreach (PropertyInfo pi in propertys)
                {
                    tempName = pi.Name;//将属性名称赋值给临时变量  
                    //检查DataTable是否包含此列（列名==对象的属性名）    
                    if (dt.Columns.Contains(tempName))
                    {
                        // 判断此属性是否有Setter  
                        if (!pi.CanWrite) continue;//该属性不可写，直接跳出  
                        //取值  
                        object value = dr[tempName];
                        //如果非空，则赋给对象的属性  
                        if (value != DBNull.Value)
                            pi.SetValue(t, value, null);
                    }
                }
                //对象添加到泛型集合中  
                ts.Add(t);
            }
            return ts;
        }
    }
}

　　OK，这是引用类型的list转datatable，完毕。