using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
namespace ConsoleApplication16
{
public static class ListAndDataTableExtension
{
public static DataTable ToDataTable<T>(this List<T> list) where T : new()
{
DataTable table = new DataTable();
PropertyInfo[] ps = typeof(T).GetProperties();
ps.ToList().ForEach(p => {
if (!p.PropertyType.IsGenericType)
{
table.Columns.Add(p.Name, p.PropertyType);
}
else
{
if (p.PropertyType.GetGenericTypeDefinition() == typeof(Nullable<>))
{
table.Columns.Add(p.Name,Nullable.GetUnderlyingType(p.PropertyType));
}
}
});
list.ForEach(obj => {
DataRow row = table.NewRow();
ps.ToList().ForEach(p => {
row[p.Name] = p.GetValue(obj);
});
table.Rows.Add(row);
});
return table;
}
public static List<T> ToList<T>(this DataTable table) where T : new()
{
List<T> list = new List<T>();
PropertyInfo[] ps = typeof(T).GetProperties();
foreach (DataRow row in table.Rows)
{
T obj = new T();
foreach (DataColumn col in table.Columns)
{
ps.ToList().ForEach(p => {
if (p.Name == col.ColumnName)
{
if (!p.PropertyType.IsGenericType)
{
p.SetValue(obj, string.IsNullOrEmpty(row[p.Name].ToString()) ? null : Convert.ChangeType(row[p.Name], p.PropertyType));
}
else
{
if (p.PropertyType.GetGenericTypeDefinition() == typeof(Nullable<>))
{
p.SetValue(obj,string.IsNullOrEmpty(row[p.Name].ToString())?null:Convert.ChangeType(row[p.Name],Nullable.GetUnderlyingType(p.PropertyType)));
}
}
}
});
}
list.Add(obj);
}
return list;
}
}
public class Studen
{
public int? StuNo { get; set; }
public string Name { get; set; }
public string Sex { get; set; }
public int Age { get; set; }
public override string ToString()
{
string s = string.Empty;
PropertyInfo[] ps = typeof(Studen).GetProperties();
ps.ToList().ForEach(p => { s += p.Name + " " + p.GetValue(this).ToString(); });
return s;
}
}
class Program
{
public static List<Studen> stuList = new List<Studen>();
static void Main(string[] args)
{
for (int i = 1; i <=14; i++)
{
stuList.Add(new Studen() { StuNo=i,Name=i.ToString(),Sex=i.ToString(),Age=i});
}
DataTable table = stuList.ToDataTable<Studen>();
List<Studen> stus = table.ToList<Studen>();
DataTable table2 = table.Clone();
DataTable table3 = table.Clone();
int rows = table.Rows.Count;
int pageSize = 5;
int pages = rows / pageSize;
foreach (DataRow oldRow in table.Rows)
{
DataRow NewRow = table3.NewRow();
NewRow.ItemArray = oldRow.ItemArray;
table3.Rows.Add(NewRow);
}
if (rows <= pageSize)
{
//分页插入的时候每次清空上次的数据
table2.Rows.Clear();
for (int i = 1; i <= rows; i++)
{
DataRow oldRow = table.Rows[i - 1];
DataRow newRow = table2.NewRow();
newRow.ItemArray = oldRow.ItemArray;
table2.Rows.Add(newRow);
}
Console.WriteLine("第一页的数据如下:");
List<Studen> students = table2.ToList<Studen>();
students.ForEach(obj => { Console.WriteLine(string.Format(obj.ToString())); });
//这里行bulkcopy的插入语句直接传入DataTable
}
else
{
for (int pageIndex = 1; pageIndex <=pages; pageIndex++)
{
Console.WriteLine(string.Format("第{0}页数据如下:",pageIndex));
//分页插入的时候每次清空上次的数据
table2.Rows.Clear();
for (int j = (pageIndex - 1) * pageSize + 1; j <= pageIndex * pageSize; j++)
{
DataRow oldRow = table.Rows[j - 1];
DataRow newRow = table2.NewRow();
newRow.ItemArray = oldRow.ItemArray;
table2.Rows.Add(newRow);
Console.WriteLine(table.ToList<Studen>()[j-1].ToString());
//这里行bulkcopy的插入语句直接传入DataTable
}
}
if (rows % pageSize != 0)
{
//分页插入的时候每次清空上次的数据
table2.Rows.Clear();
int skip = rows % pageSize;
Console.WriteLine(string.Format("最后一页数据如下:"));
for (int j = pages * pageSize + 1; j <= pageSize * pages + skip; j++)
{
DataRow oldRow = table.Rows[j - 1];
DataRow newRow = table2.NewRow();
newRow.ItemArray = oldRow.ItemArray;
table2.Rows.Add(newRow);
Console.WriteLine(table.ToList<Studen>()[j - 1].ToString());
//这里行bulkcopy的插入语句直接传入DataTable
}
}
}
#region 大小写间隔 转换成大写加下划线
string s = "AbcDefGhi";
s = Regex.Replace(s, @"([A-Z]{1})([a-z]*)", MatchEval);
s = s.TrimEnd('_');
#endregion
#region 大写下划线 转换成 大小写间隔
string s2 = "ABC_EDF_FSD";
List<string> strList = s2.Split('_').ToList();
s2 = "";
foreach (string str in strList)
{
s2 += Regex.Replace(str, @"([A-Za-z]{1})([A-Za-z]*)", MatchEvalEntity);
}
#endregion
Console.ReadKey();
}
private static string MatchEvalEntity(Match match)
{
return match.Groups[1].Value.ToUpper() + match.Groups[2].Value.ToLower();
}
private static string MatchEval(Match match)
{
return match.Groups[1].Value.ToUpper() + match.Groups[2].Value.ToUpper()+"_";
}
}
}