EF Code First：如何从nuget包控制台查看'EntityValidationErrors'属性？-Java 学习之路

122

我为此感到茫然：

我已经为实体框架（4.1.3）代码第一种方法定义了我的类 . 一切都很好（我正在制作 table 等），直到我开始播种 .

现在当我这样做的时候

Add-Migration "remigrate" ; Update-Database;

我在程序包控制台上收到错误“一个或多个实体的验证失败 . 有关详细信息，请参阅'EntityValidationErrors'属性 . ”

我的Seed（）方法中有一个断点但因为我对如何获取细节毫无头绪（PS - 我看过线程Validation failed for one or more entities while saving changes to SQL Server Database using Entity Framework，它显示了我如何看到该属性 . ）

我知道我的Seed（）方法有问题，因为如果我在方法调用之后立即返回，则错误消失 . 那么如何设置断点以便我可以看到验证错误是什么？有点失落 . 或者是否有其他方法可以在nuget控制台中跟踪它？

6 回答

210

我最近也对此感到恼火 . 我通过在Seed方法的Configuration类中放置一个包装器函数来修复它，并通过调用我的函数来替换对 SaveChanges 的调用 . 此函数将简单地枚举 EntityValidationErrors 集合中的错误，并重新抛出异常消息列出各个问题的异常 . 这使得输出显示在NuGet包管理器控制台中 .

代码如下：

/// <summary>
/// Wrapper for SaveChanges adding the Validation Messages to the generated exception
/// </summary>
/// <param name="context">The context.</param>
private void SaveChanges(DbContext context) {
    try {
        context.SaveChanges();
    } catch (DbEntityValidationException ex) {
        StringBuilder sb = new StringBuilder();

        foreach (var failure in ex.EntityValidationErrors) {
            sb.AppendFormat("{0} failed validation\n", failure.Entry.Entity.GetType());
            foreach (var error in failure.ValidationErrors) {
                sb.AppendFormat("- {0} : {1}", error.PropertyName, error.ErrorMessage);
                sb.AppendLine();
            }
        }

        throw new DbEntityValidationException(
            "Entity Validation Failed - errors follow:\n" + 
            sb.ToString(), ex
        ); // Add the original exception as the innerException
    }
}

只需在种子方法中用 SaveChanges(context) 替换 context.SaveChanges() 的调用 .

回复于 2024-05-10T06:14:24+08:00

Extend Your DBContext Class Already With a Partial Class Definition!

如果您查看DbContext的类定义，它将类似于以下内容：

// DatabaseContext.cs   -- This file is auto generated and thus shouldn't be changed. 
public partial class [DatabaseContextName] : DbContext { ... }

因此，在另一个文件中，您可以创建相同的定义并覆盖您想要的部分 .

// partialDatabaseContext.cs  -- you can safely make changes 
// that will not be overwritten in here.
public partial class [DatabaseContextName] : DbContext { // Override defaults here }

部分类的整个想法 - 你注意到 DbContext 是一个部分类 - 是你可以扩展一个已生成的类（或将类组织成多个文件），在我们的例子中我们也想 override SaveChanges 方法从添加到 DbContext 的部分类中 .

这样我们就可以从所有现有的DbContext / SaveChanges调用中获取错误调试信息，而不必更改种子代码或开发代码 .

这就是我要做的事情（ NOTE ，不同之处在于我只是在我们自己编写的 DbContext 部分类中重写了SaveChanges方法，而不是生成的一个） . 另外，请确保您的部分课程使用 correct namespace ，否则您将撞到墙上 .

public partial class Database : DbContext
{
    public override int SaveChanges()
    {
        try
        {
            return base.SaveChanges();
        }
        catch (DbEntityValidationException ex)
        {
            var sb = new StringBuilder();

            foreach (var failure in ex.EntityValidationErrors)
            {
                sb.AppendFormat("{0} failed validation\n", failure.Entry.Entity.GetType());
                foreach (var error in failure.ValidationErrors)
                {
                    sb.AppendFormat("- {0} : {1}", error.PropertyName, error.ErrorMessage);
                    sb.AppendLine();
                }
            }

            throw new DbEntityValidationException(
                "Entity Validation Failed - errors follow:\n" +
                sb.ToString(), ex
                ); // Add the original exception as the innerException
        }
    }
}

回复于 2024-05-10T06:14:24+08:00

我将Richards的答案转换为扩展方法：

public static int SaveChangesWithErrors(this DbContext context)
    {
        try
        {
            return context.SaveChanges();
        }
        catch (DbEntityValidationException ex)
        {
            StringBuilder sb = new StringBuilder();

            foreach (var failure in ex.EntityValidationErrors)
            {
                sb.AppendFormat("{0} failed validation\n", failure.Entry.Entity.GetType());
                foreach (var error in failure.ValidationErrors)
                {
                    sb.AppendFormat("- {0} : {1}", error.PropertyName, error.ErrorMessage);
                    sb.AppendLine();
                }
            }

            throw new DbEntityValidationException(
                "Entity Validation Failed - errors follow:\n" +
                sb.ToString(), ex
            ); // Add the original exception as the innerException
        }
    }

像这样打电话：

context.SaveChangesWithErrors();

回复于 2024-05-10T06:14:24+08:00

我将craigvl的版本转换为C＃我必须添加context.SaveChanges（）;为了它对我有用，如下所示 .

try
{
    byte[] bytes = System.IO.File.ReadAllBytes(@"C:\Users\sheph_000\Desktop\Rawr.png");
    Console.WriteLine(bytes);

    context.BeverageTypes.AddOrUpdate(
        x => x.Name,
        new AATPos.DAL.Entities.BeverageType { ID = 1, Name = "Sodas" }
        );

    context.Beverages.AddOrUpdate(
        x => x.Name,
        new AATPos.DAL.Entities.Beverage { ID = 1, Name = "Coke", BeverageTypeID = 1, ImageData = bytes, IsStocked = true, StockLevel = 10, Price = 10.00M, ImageMimeType = "test" },
        new AATPos.DAL.Entities.Beverage { ID = 2, Name = "Fanta", BeverageTypeID = 1, ImageData = bytes, IsStocked = true, StockLevel = 10, Price = 10.00M, ImageMimeType = "test" },
        new AATPos.DAL.Entities.Beverage { ID = 3, Name = "Sprite", BeverageTypeID = 1, ImageData = bytes, IsStocked = true, StockLevel = 10, Price = 10.00M, ImageMimeType = "test" },
        new AATPos.DAL.Entities.Beverage { ID = 4, Name = "Cream Soda", BeverageTypeID = 1, ImageData = bytes, IsStocked = true, StockLevel = 10, Price = 10.00M, ImageMimeType = "test" },
        new AATPos.DAL.Entities.Beverage { ID = 5, Name = "Pepsi", BeverageTypeID = 1, ImageData = bytes, IsStocked = true, StockLevel = 10, Price = 10.00M, ImageMimeType = "test" }
        );

    context.SaveChanges();
}
catch (System.Data.Entity.Validation.DbEntityValidationException ex)
{
    var sb = new System.Text.StringBuilder();
    foreach (var failure in ex.EntityValidationErrors)
            {
                sb.AppendFormat("{0} failed validation", failure.Entry.Entity.GetType());
        foreach (var error in failure.ValidationErrors)
                {
            sb.AppendFormat("- {0} : {1}", error.PropertyName, error.ErrorMessage);
            sb.AppendLine();
                }
            }

    throw new Exception(sb.ToString());
}

回复于 2024-05-10T06:14:24+08:00

110

理查德感谢让我在正确的道路上（有相同的问题）下面是一个替代品，没有包装器，这在迁移配置种子方法中对我有用：

Protected Overrides Sub Seed(context As NotificationContext)

        Try
            context.System.AddOrUpdate(
               Function(c) c.SystemName,
                New E_NotificationSystem() With {.SystemName = "System1"},
                New E_NotificationSystem() With {.SystemName = "System2"},
                New E_NotificationSystem() With {.SystemName = "System3"})

            context.SaveChanges()

        Catch ex As DbEntityValidationException

            Dim sb As New StringBuilder

            For Each failure In ex.EntityValidationErrors

                sb.AppendFormat("{0} failed validation" & vbLf, failure.Entry.Entity.[GetType]())

                For Each [error] In failure.ValidationErrors
                    sb.AppendFormat("- {0} : {1}", [error].PropertyName, [error].ErrorMessage)
                    sb.AppendLine()
                Next
            Next

            Throw New Exception(sb.ToString())

        End Try
End Sub

然后能够在包管理器控制台中看到异常 . 希望这有助于某人 .

回复于 2024-05-10T06:14:24+08:00

I Also had same model validation problem but successfully catch by myself after lot of thinking;

I use reverse engineering method to catch the problem out of Over 80 + Model Classes;

1> Made copy of dbcontext, changing the name (I add "1" at end and make respective changes in class constructor and initialization etc.

Old:
 
>public class AppDb : IdentityDbContext<ApplicationUser>
>     
> {
> public AppDb(): base("DefaultConnection", throwIfV1Schema: false)
> {
> 
> }
>     
> public static AppDb Create()
>{
>return new AppDb();
>} 

**New:**

>public class AppDb1 : IdentityDbContext<ApplicationUser>
>{
>public AppDb1()
>: base("DefaultConnection", throwIfV1Schema: false)
>{
>}
> 
>public static AppDb1 Create()
> {
> return new AppDb1();
>  }`

...
2> Make changes to Codefirst Migration Configuration from Old DbContext to my new Context.

> internal sealed class Configuration :
> DbMigrationsConfiguration<DAL.AppDb1> { public Configuration() {
> AutomaticMigrationsEnabled = false; }    protected override void
> Seed(DAL.AppDb1 context) {`

3> Comment the Dbsets in new DbContext which was doubt.
4> Apply update migration if succeeded the probelm lye in Commented section.
5> if not then commented section is clear of bug clear.
6> repeat the (4) until found the right place of bug.
7> Happy Codding

回复于 2024-05-10T06:14:24+08:00

EF Code First：如何从nuget包控制台查看'EntityValidationErrors'属性？

6 回答

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