DataTable 转换成匿名集合类

using System;
using System.CodeDom.Compiler;
using System.Collections.Generic;
using System.Data;
using System.Diagnostics;
using System.Linq;
using System.Reflection;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using Contract.Domain;
using DevExpress.Data;
using Framework;
using Holworth.Utility;
using HraWeb.Common;
using Holworth.RiskInterface;
using System.Net;
using System.IO;
using System.Text;
using Contract.IService;
using HraModel;
using NPOI.SS.Formula.Functions;
using Oracle.DataAccess.Client;
using OracleConnection = System.Data.OracleClient.OracleConnection;
using System.Collections;
using System.Text.RegularExpressions;
using Match = System.Text.RegularExpressions.Match;
using HraWeb.ReportEg.To38Validate.Validate;
using Microsoft.CSharp;

namespace HraWeb
{
public static class ListAndTableExtension
{
#region 集合转为对应的DataTable

/// <summary>
///List转换为DataTable
/// </summary>
/// <typeparam name="T">泛型类型</typeparam>
/// <param name="list"></param>
/// <returns></returns>
public static DataTable ToDataTable<T>(this List<T> list) where T : new()
{
DataTable table = new DataTable();
PropertyInfo[] ps = typeof(T).GetProperties();
foreach (PropertyInfo p in ps)
{
if (!p.PropertyType.IsGenericType)
{
table.Columns.Add(ConvertToTableColumnName(p.Name), p.PropertyType);

}
else
{
Type GenericTypeDefinition = p.PropertyType.GetGenericTypeDefinition();
if (GenericTypeDefinition == typeof(Nullable<>))
{
table.Columns.Add(ConvertToTableColumnName(p.Name), Nullable.GetUnderlyingType(p.PropertyType));

}
}
}
foreach (T obj in list)
{
DataRow row = table.NewRow();
foreach (PropertyInfo p in ps)
{

row[ConvertToTableColumnName(p.Name)] = p.GetValue(obj, null);

}
table.Rows.Add(row);

}
return table;

}

#endregion

#region 扩展方法 DataTable转为对应实体的List集合

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)
{
foreach (PropertyInfo p in ps)
{
if (p.Name == ConvertToEntityColumnName(col.ColumnName))
{
if (!p.PropertyType.IsGenericType)
{
p.SetValue(obj,
string.IsNullOrEmpty(row[col.ColumnName].ToString())
? null
: Convert.ChangeType(row[col.ColumnName].ToString(), p.PropertyType), null);

}
else
{
if (p.PropertyType.GetGenericTypeDefinition() == typeof(Nullable<>))
{
p.SetValue(obj,
string.IsNullOrEmpty(row[col.ColumnName].ToString())
? null
: Convert.ChangeType(row[col.ColumnName],
Nullable.GetUnderlyingType(p.PropertyType)), null);

}
}

}
}

}
list.Add(obj);
}
return list;
}

#endregion

#region 列名转为对应实体类的属性名

public static string ConvertToEntityColumnName(string name)
{

List<string> strList = name.Split('_').ToList();
StringBuilder sb = new StringBuilder();
foreach (string s2 in strList)
{
sb.Append(ReplaceString(s2));
}
return sb.ToString();
}

public static string ReplaceString(string s)
{
return Regex.Replace(s, (string)@"([A-Za-z]{1})([A-Za-z]*)", (MatchEvaluator)MathcEval);

}

private static string MathcEval(Match match)
{
return match.Groups[1].Value.ToUpper() + match.Groups[2].Value.ToLower();
}

#endregion
public static IList ToGenericList(this DataTable dataTable)
{
Type GenericType = ListAndTableExtension.InitEntityType(dataTable);
Type typeMaster = typeof(List<>);
Type listType = typeMaster.MakeGenericType(GenericType);
IList list = Activator.CreateInstance(listType) as IList;
if (dataTable == null || dataTable.Rows.Count == 0)
return list;
var constructor = GenericType.GetConstructors(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance)
.OrderBy(c => c.GetParameters().Length).First();
var parameters = constructor.GetParameters();
var values = new object[parameters.Length];
foreach (DataRow dr in dataTable.Rows)
{
int index = 0;
foreach (ParameterInfo item in parameters)
{
object itemValue = null;
if (dr[item.Name] != null && dr[item.Name] != DBNull.Value)
{
itemValue = Convert.ChangeType(dr[item.Name], item.ParameterType);
}
values[index++] = itemValue;
}

list.Add(constructor.Invoke(values));

}
return list;
}
#region 属性名转换为数据库对应的列名

//属性名转换为数据库对应的列名
public static string ConvertToTableColumnName(string name)
{
name = Regex.Replace(name, @"([A-Z]{1})([a-z]*)", MatchEval);
name = name.TrimEnd('_');
return name;
}

private static string MatchEval(Match match)
{
return match.Groups[1].Value.ToUpper() + match.Groups[2].Value.ToUpper() + "_";
}

private static Type InitEntityType(DataTable table)
{
CSharpCodeProvider p = new CSharpCodeProvider();
CompilerParameters param = new CompilerParameters();
string s = "namespace __ns" +
"{" +
"public class AAA";
//"{ public AAA(string Name,int ID,string GuidType){this.Name=Name;this.ID=ID;this.GuidType=GuidType;}" +
//" public string Name{ get;set; }" +
//" public int ID{get;set;}" +
//" public string GuidType{get;set;}" +
s += "{ " +
"public AAA(";
for (int i = 0; i < table.Columns.Count;i++)
{

s += "string " + table.Columns[i].ColumnName+",";

}
s = s.TrimEnd(',')+"){";
for (int i = 0; i < table.Columns.Count; i++)
{
s += "this." + table.Columns[i].ColumnName + "="+table.Columns[i].ColumnName+";";
}
s += "}";
for (int i = 0; i < table.Columns.Count; i++)
{
string columnName = table.Columns[i].ColumnName;
s += " public string " + columnName + " {get;set;}\r\n";
}
s +=" }}\r\n";

List<object> objs = new List<object>();
for (int i = 0; i < table.Columns.Count; i++)
{
objs.Add("");
}

CompilerResults rel = p.CompileAssemblyFromSource(param, s);
Type t = rel.CompiledAssembly.GetType("__ns.AAA");

object o = t.GetConstructors(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance)
.OrderBy(c => c.GetParameters().Length).First().Invoke(objs.ToArray());

return o.GetType();
}

public static void TestMethod()
{
var entity = new { Name = "item", ID = 0, GuidType = "" };

DataTable dataTable = new DataTable();
dataTable.Columns.Add("Name", typeof(string));
dataTable.Columns.Add("ID", typeof(int));
dataTable.Columns.Add("GuidType", typeof(string));

for (int i = 0; i < 10; i++)
{
DataRow dr = dataTable.NewRow();
dr["Name"] = "STRING" + i;
dr["ID"] = i;
if (i % 2 == 0)
dr["GuidType"] = "GuidType" + i;
else
{
dr["GuidType"] = DBNull.Value;
}
dataTable.Rows.Add(dr);
}

IList list = dataTable.ToGenericList();
}

#endregion

}
}