Entity Framework本身的增刪改查其實 已經很方便了，不過做項目的時候用的多了也就覺得有點累了，每個業務實體基本上都涉及到到了增刪改查這四個基本的要素，至於封裝每個公司可能都不一樣，接口，設計模式都用的眼花繚亂，我閑來沒事就搞個簡單的封裝Helper，Github上也有關於EF的擴展Libray，具體沒有用過，公司的有自己的封裝，自己也沒怎么弄，具體地址:https://github.com/loresoft/EntityFramework.Extended.
首先來看段代碼，model和context是從數據中直接生成，你可以選擇自己習慣的方式:
//新增
User addUser = new User();
addUser.PersonID = 3;
addUser.UserName = "keso";
dbContext.Entry<User>(addUser).State = EntityState.Added;
dbContext.SaveChanges();
//修改
User updateUser = new User();
dbContext.Users.Where(item => item.ID == 2).OrderBy(item => item.ID);
updateUser.UserName = updateUser.UserName + "測試";
dbContext.Entry<User>(updateUser).State = EntityState.Modified;
dbContext.SaveChanges();
//刪除
User delUser = dbContext.Users.Where(item => item.ID == 2).First();
dbContext.Entry<User>(delUser).State = EntityState.Deleted;
dbContext.SaveChanges();
如果每個業務實體都這么寫一遍，估計公司水准有待提高，而且開發的也該跳起來罵人，本人只是簡單封裝下新建一個EFHelper，實際開發會封裝的更多，不過底層處理是不變的
class EFHelpler<T> where T : class
{
//...
}
新增
方法:
/// <summary>
/// 實體新增
/// </summary>
/// <param name="model"></param>
public void add(params T[] paramList)
{
foreach (var model in paramList)
{
dbContext.Entry<T>(model).State = EntityState.Added;
}
dbContext.SaveChanges();
}
調用:
EFHelpler<User> helper = new EFHelpler<User>();
BaseContext dbContext = new BaseContext();
//新增
List<User> listUser = new List<User>();
for (int i = 0; i < 2; i++)
{
User user = new User();
user.PersonID = i;
user.UserName = "FlyElehant" + i;
listUser.Add(user);
}
helper.add(listUser.ToArray());
Console.WriteLine("新增成功");
查詢
查詢分了兩種，一種是簡單的查詢，一種是分頁的：
/// <summary>
/// 實體查詢
/// </summary>
public IEnumerable<T> getSearchList(System.Linq.Expressions.Expression<Func<T, bool>> where)
{
return dbContext.Set<T>().Where(where);
}
/// <summary>
/// 實體分頁查詢
/// </summary>
/// <typeparam name="TKey"></typeparam>
/// <param name="where"></param>
/// <param name="orderBy"></param>
/// <param name="pageSize"></param>
/// <param name="pageIndex"></param>
/// <returns></returns>
public IEnumerable<T> getSearchListByPage<TKey>(Expression<Func<T, bool>> where, Expression<Func<T, TKey>> orderBy, int pageSize, int pageIndex)
{
return dbContext.Set<T>().Where(where).OrderByDescending(orderBy).Skip((pageIndex - 1) * pageSize).Take(pageSize);
}
簡單調用，第二個方式除了分頁之外，主要是查詢的時候指定一定OrderBy的類型，也就是TKey:
var query = helper.getSearchList(item => item.UserName.Contains("keso"));
var queryMulti = helper.getSearchListByPage<int>(item => item.UserName.Contains("FlyElehant"), order => order.PersonID, 2, 1);
query = queryMulti;
foreach (User user in query)
{
Console.WriteLine(user.UserName);
}
修改
修改代碼稍微讀了幾行，主要是用到了一下反射:
/// <summary>
/// 按照條件修改數據
/// </summary>
/// <param name="where"></param>
/// <param name="dic"></param>
public void update(Expression<Func<T, bool>> where, Dictionary<string, object> dic)
{
IEnumerable<T> result = dbContext.Set<T>().Where(where).ToList();
Type type = typeof(T);
List<PropertyInfo> propertyList = type.GetProperties(System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.Instance).ToList();
//遍歷結果集
foreach (T entity in result)
{
foreach (PropertyInfo propertyInfo in propertyList)
{
string propertyName = propertyInfo.Name;
if (dic.ContainsKey(propertyName))
{
//設置值
propertyInfo.SetValue(entity, dic[propertyName], null);
}
}
}
dbContext.SaveChanges();
}
調用:
Dictionary<string,object> dic=new Dictionary<string,object>();
dic.Add("PersonID",2);
dic.Add("UserName","keso");
helper.update(item => item.UserName.Contains("keso"), dic);
Console.WriteLine("修改成功");
刪除
方法:
/// <summary>
/// 實體刪除
/// </summary>
/// <param name="model"></param>
public void delete(params T[] paramList)
{
foreach (var model in paramList)
{
dbContext.Entry<T>(model).State = EntityState.Deleted;
}
dbContext.SaveChanges();
}
調用:
var query = helper.getSearchList(item => item.UserName.Contains("keso"));
helper.delete(query.ToArray());
完整的EFHelper:
class EFHelpler<T> where T : class
{
BaseContext dbContext = new BaseContext();
/// <summary>
/// 實體新增
/// </summary>
/// <param name="model"></param>
public void add(params T[] paramList)
{
foreach (var model in paramList)
{
dbContext.Entry<T>(model).State = EntityState.Added;
}
dbContext.SaveChanges();
}
/// <summary>
/// 實體查詢
/// </summary>
public IEnumerable<T> getSearchList(System.Linq.Expressions.Expression<Func<T, bool>> where)
{
return dbContext.Set<T>().Where(where);
}
/// <summary>
/// 實體分頁查詢
/// </summary>
/// <typeparam name="TKey"></typeparam>
/// <param name="where"></param>
/// <param name="orderBy"></param>
/// <param name="pageSize"></param>
/// <param name="pageIndex"></param>
/// <returns></returns>
public IEnumerable<T> getSearchListByPage<TKey>(Expression<Func<T, bool>> where, Expression<Func<T, TKey>> orderBy, int pageSize, int pageIndex)
{
return dbContext.Set<T>().Where(where).OrderByDescending(orderBy).Skip((pageIndex - 1) * pageSize).Take(pageSize);
}
/// <summary>
/// 實體刪除
/// </summary>
/// <param name="model"></param>
public void delete(params T[] paramList)
{
foreach (var model in paramList)
{
dbContext.Entry<T>(model).State = EntityState.Deleted;
}
dbContext.SaveChanges();
}
/// <summary>
/// 按照條件修改數據
/// </summary>
/// <param name="where"></param>
/// <param name="dic"></param>
public void update(Expression<Func<T, bool>> where, Dictionary<string, object> dic)
{
IEnumerable<T> result = dbContext.Set<T>().Where(where).ToList();
Type type = typeof(T);
List<PropertyInfo> propertyList = type.GetProperties(System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.Instance).ToList();
//遍歷結果集
foreach (T entity in result)
{
foreach (PropertyInfo propertyInfo in propertyList)
{
string propertyName = propertyInfo.Name;
if (dic.ContainsKey(propertyName))
{
//設置值
propertyInfo.SetValue(entity, dic[propertyName], null);
}
}
}
dbContext.SaveChanges();
}
}
個人Demo難免有表達不當或者技術失誤的地方，如有不當，請多多指出，感激不盡~