using System;
using System.Collections.Generic;
using System.Data;
using System.Data.OleDb;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Windows.Forms;


namespace CommonUtil
{
public class DataBaseUtil
{

//传递数据库文件路径，这里使用的是access2007数据库
public DataBaseUtil(string path)
{
Path = path;
ConnStr = string.Format(@"Provider=Microsoft.ACE.OLEDB.12.0;Data Source={0};Persist Security Info=False; ",
path);
conn = new OleDbConnection(ConnStr);
}
public string Path;
public static string ConnStr = @"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=E:\\numdb.accdb;Persist Security Info=False; ";

private OleDbConnection conn= new OleDbConnection(ConnStr);//创建一个connection对象

//使用泛型，获取所有的实体类对象，返回list
public List ReieveList() where T : class,new()
{
try
{
var className = (typeof(T)).Name;
var sql = string.Format("SELECT * FROM {0}", className);
OleDbDataAdapter da = new OleDbDataAdapter(sql, ConnStr);
DataSet ds = new DataSet();
da.Fill(ds);
var dt = ds.Tables[0];

var list = ConverterUtil.ConvertDataTableToList(dt);

return list;
}
catch (Exception e)
{

MessageBox.Show(e.Message);
return null;
}

}

//同上，根据条件，查询，返回list实体类列表

public List ReieveList(string where) where T : class,new()
{
try
{
var className = (typeof(T)).Name;
var sql = string.Format("SELECT * FROM {0} {1}", className,where);
OleDbDataAdapter da = new OleDbDataAdapter(sql, ConnStr);

DataSet ds = new DataSet();
da.Fill(ds);

var dt = ds.Tables[0];

var list = ConverterUtil.ConvertDataTableToList(dt);

return list;
}
catch (Exception e)
{

MessageBox.Show(e.Message);
return null;
}

}

//插入一条数据
public bool Insert(T entity) where T : class,new()
{

try
{
var type = typeof (T);
var className = type.Name;

var fields = "";
var values = "";

foreach (var property in type.GetProperties())
{
if (property.Name.Equals("ID")) continue;
fields += "," + property.Name;
var isNumStr = (property.PropertyType == typeof (double) ||
property.PropertyType == typeof (int))
? ""
: "'";
values += "," + isNumStr + property.GetValue(entity, null) + isNumStr;
}
fields = fields.Substring(1);
values = values.Substring(1);
var sql = string.Format("insert into {0}({1}) values ({2}) ", className,
fields, values);

OleDbDataAdapter da = new OleDbDataAdapter();


da.InsertCommand = new OleDbCommand(sql, conn);
da.InsertCommand.CommandText = sql;

conn.Open();
da.InsertCommand.ExecuteNonQuery();
conn.Close();

return true;
}
catch (Exception e)
{

MessageBox.Show(e.Message);
return false;
}
finally
{
conn.Close();
}

}

//更新实体类

public bool Update(T entity) where T : class,new()
{

try
{
var type = typeof(T);
var className = type.Name;

var values = "";

var id = "";
foreach (var property in type.GetProperties())
{
if (property.Name.Equals("ID"))
{
id = " where ID="+ property.GetValue(entity, null).ToString();
continue;
}
var isNumStr = (property.PropertyType == typeof(double) ||
property.PropertyType == typeof(int))
? ""
: "'";
values += "," +property.Name +"="+ isNumStr + property.GetValue(entity, null) + isNumStr;
}
values = values.Substring(1);
var s