我想保存我的编辑到数据库，我使用实体框架代码-在ASP。NET MVC 3 / c#，但我得到错误。在我的事件类中，我有DateTime和TimeSpan数据类型，但在我的数据库中，我分别有日期和时间。这就是原因吗?在将更改保存到数据库之前，如何在代码中转换为适当的数据类型。
public class Event
{
public int EventId { get; set; }
public int CategoryId { get; set; }
public int PlaceId { get; set; }
public string Title { get; set; }
public decimal Price { get; set; }
public DateTime EventDate { get; set; }
public TimeSpan StartTime { get; set; }
public TimeSpan EndTime { get; set; }
public string Description { get; set; }
public string EventPlaceUrl { get; set; }
public Category Category { get; set; }
public Place Place { get; set; }
}
方法>>>>在storeDB.SaveChanges()中的问题;
// POST: /EventManager/Edit/386
[HttpPost]
public ActionResult Edit(int id, FormCollection collection)
{
var theEvent = storeDB.Events.Find(id);
if (TryUpdateModel(theEvent))
{
storeDB.SaveChanges();
return RedirectToAction("Index");
}
else
{
ViewBag.Categories = storeDB.Categories.OrderBy(g => g.Name).ToList();
ViewBag.Places = storeDB.Places.OrderBy(a => a.Name).ToList();
return View(theEvent);
}
}
与
public class EventCalendarEntities : DbContext
{
public DbSet<Event> Events { get; set; }
public DbSet<Category> Categories { get; set; }
public DbSet<Place> Places { get; set; }
}
SQL Server 2008 R2数据库
EventDate (Datatype = date)
StartTime (Datatype = time)
EndTime (Datatype = time)
Http表单
EventDate (Datatype = DateTime) e.g. 4/8/2011 12:00:00 AM
StartTime (Datatype = Timespan/time not sure) e.g. 08:30:00
EndTime (Datatype = Timespan/time not sure) e.g. 09:00:00
“/”应用程序中的服务器错误。
一个或多个实体验证失败。更多细节请参见'EntityValidationErrors'属性。
描述:在执行当前web请求期间发生了一个未处理的异常。请查看堆栈跟踪以获得有关错误及其在代码中的起源位置的更多信息。
System.Data.Entity.Validation.DbEntityValidationException:一个或多个实体验证失败。更多细节请参见'EntityValidationErrors'属性。
源错误:
Line 75: if (TryUpdateModel(theEvent))
Line 76: {
Line 77: storeDB.SaveChanges();
Line 78: return RedirectToAction("Index");
Line 79: }
源文件:C:\sep\MvcEventCalendar\MvcEventCalendar\Controllers\EventManagerController.cs
堆栈跟踪:
[DbEntityValidationException:一个或多个实体验证失败。]更多细节请参见'EntityValidationErrors'属性。]
这个实现用详细文本将实体异常包装到异常之间。
它处理DbEntityValidationException, DbUpdateException, datetime2范围错误(MS SQL)，并在消息中包括无效实体的键(在SaveChanges调用中保存多个实体时有用)。
首先，在DbContext类中重写SaveChanges:
public class AppDbContext : DbContext
{
public override int SaveChanges()
{
try
{
return base.SaveChanges();
}
catch (DbEntityValidationException dbEntityValidationException)
{
throw ExceptionHelper.CreateFromEntityValidation(dbEntityValidationException);
}
catch (DbUpdateException dbUpdateException)
{
throw ExceptionHelper.CreateFromDbUpdateException(dbUpdateException);
}
}
public override async Task<int> SaveChangesAsync(CancellationToken cancellationToken)
{
try
{
return await base.SaveChangesAsync(cancellationToken);
}
catch (DbEntityValidationException dbEntityValidationException)
{
throw ExceptionHelper.CreateFromEntityValidation(dbEntityValidationException);
}
catch (DbUpdateException dbUpdateException)
{
throw ExceptionHelper.CreateFromDbUpdateException(dbUpdateException);
}
}
ExceptionHelper经济舱:
public class ExceptionHelper
{
public static Exception CreateFromEntityValidation(DbEntityValidationException ex)
{
return new Exception(GetDbEntityValidationMessage(ex), ex);
}
public static string GetDbEntityValidationMessage(DbEntityValidationException ex)
{
// Retrieve the error messages as a list of strings.
var errorMessages = ex.EntityValidationErrors
.SelectMany(x => x.ValidationErrors)
.Select(x => x.ErrorMessage);
// Join the list to a single string.
var fullErrorMessage = string.Join("; ", errorMessages);
// Combine the original exception message with the new one.
var exceptionMessage = string.Concat(ex.Message, " The validation errors are: ", fullErrorMessage);
return exceptionMessage;
}
public static IEnumerable<Exception> GetInners(Exception ex)
{
for (Exception e = ex; e != null; e = e.InnerException)
yield return e;
}
public static Exception CreateFromDbUpdateException(DbUpdateException dbUpdateException)
{
var inner = GetInners(dbUpdateException).Last();
string message = "";
int i = 1;
foreach (var entry in dbUpdateException.Entries)
{
var entry1 = entry;
var obj = entry1.CurrentValues.ToObject();
var type = obj.GetType();
var propertyNames = entry1.CurrentValues.PropertyNames.Where(x => inner.Message.Contains(x)).ToList();
// check MS SQL datetime2 error
if (inner.Message.Contains("datetime2"))
{
var propertyNames2 = from x in type.GetProperties()
where x.PropertyType == typeof(DateTime) ||
x.PropertyType == typeof(DateTime?)
select x.Name;
propertyNames.AddRange(propertyNames2);
}
message += "Entry " + i++ + " " + type.Name + ": " + string.Join("; ", propertyNames.Select(x =>
string.Format("'{0}' = '{1}'", x, entry1.CurrentValues[x])));
}
return new Exception(message, dbUpdateException);
}
}
