/// <summary>
/// 异步使用附带新值的实体更新指定实体属性的值，此方法不支持事务
/// </summary>
/// <param name="propertyExpresion">属性表达式，提供要更新的实体属性</param>
/// <param name="entities">附带新值的实体属性，必须包含主键</param>
/// <returns>操作影响的行数</returns>
/// <exception cref="System.NotSupportedException"></exception>
public async Task <int> UpdateAsync(Expression <Func <TEntity, object> > propertyExpresion, params TEntity[] entities)
{
propertyExpresion.CheckNotNull("propertyExpresion");
entities.CheckNotNull("entities");
CodeFirstDbContext context = new CodeFirstDbContext();
context.Update <TEntity, TKey>(propertyExpresion, entities);
bool fail;
try
{
return(await context.SaveChangesAsync(false));
}
catch (DbUpdateConcurrencyException)
{
fail = true;
}
if (fail)
{
TKey[] ids = entities.Select(m => m.Id).ToArray();
context.Set <TEntity>().Where(m => ids.Contains(m.Id)).Load();
context.Update <TEntity, TKey>(propertyExpresion, entities);
return(await context.SaveChangesAsync(false));
}
return(0);
}
/// <summary>
/// 使用附带新值的实体更新指定实体属性的值，此方法不支持事务
/// </summary>
/// <param name="propertyExpresion">属性表达式，提供要更新的实体属性</param>
/// <param name="entities">附带新值的实体属性，必须包含主键</param>
/// <returns>操作影响的行数</returns>
/// <exception cref="System.NotSupportedException"></exception>
public int Update(Expression <Func <TEntity, object> > propertyExpresion, params TEntity[] entities)
{
propertyExpresion.CheckNotNull("propertyExpresion");
entities.CheckNotNull("entities");
CodeFirstDbContext context = new CodeFirstDbContext();
context.Update <TEntity, TKey>(propertyExpresion, entities);
try
{
return(context.SaveChanges(false));
}
catch (DbUpdateConcurrencyException)
{
TKey[] ids = entities.Select(m => m.Id).ToArray();
context.Set <TEntity>().Where(m => ids.Contains(m.Id)).Load();
context.Update <TEntity, TKey>(propertyExpresion, entities);
return(context.SaveChanges(false));
}
}
/// <summary>
/// 设置数据库初始化，策略为自动迁移到最新版本
/// </summary>
public static void Initialize()
{
CodeFirstDbContext context = new CodeFirstDbContext();
IDatabaseInitializer <CodeFirstDbContext> initializer;
if (!context.Database.Exists())
{
initializer = new CreateDatabaseIfNotExistsWithSeed();
}
else
{
initializer = new MigrateDatabaseToLatestVersion <CodeFirstDbContext, MigrationsConfiguration>();
}
Database.SetInitializer(initializer);
//EF预热，解决EF6第一次加载慢的问题
ObjectContext objectContext = ((IObjectContextAdapter)context).ObjectContext;
StorageMappingItemCollection mappingItemCollection = (StorageMappingItemCollection)objectContext.ObjectStateManager
.MetadataWorkspace.GetItemCollection(DataSpace.CSSpace);
mappingItemCollection.GenerateViews(new List <EdmSchemaError>());
context.Dispose();
}
