在 MySQL Linq Query EF6 中使用多个 Include() 方法时出现 FormatException
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【中文标题】在 MySQL Linq Query EF6 中使用多个 Include() 方法时出现 FormatException【英文标题】：FormatException when using multiple Include() methods in MySQL Linq Query EF6 【发布时间】：2015-04-25 10:51:00 【问题描述】：我正在尝试执行 LINQ 查询并多次使用Include() 来提取相关信息。
如果我执行以下查询，它可以正常工作：
var usersQuizzes = this.Context.EntitySet<Quiz>()
.Include(x => x.Questions)
.Include(x => x.QuizVersion)
.Include(x => x.QuizPasswords)
.Include(x => x.QuizVersion.Questions)
.Take(20)
.ToList();
但如果我有这样的错误：
var usersQuizzes = this.Context.EntitySet<Quiz>()
.Include(x => x.Questions)
.Include(x => x.QuizVersion)
.Include(x => x.QuizPasswords)
.Include(x => x.QuizVersion.Questions)
.Include(x => x.QuizVersions) // Added this
.Take(20)
.ToList();
或者这个：
var usersQuizzes = this.Context.EntitySet<Quiz>()
.Include(x => x.Questions)
.Include(x => x.QuizVersion)
.Include(x => x.QuizPasswords)
.Include(x => x.QuizVersion.Questions)
.Include(x => x.ResultDescriptions) // Added this instead
.Take(20)
.ToList();
或者这个：
var usersQuizzes = this.Context.EntitySet<Quiz>()
.Include(x => x.QuizVersions)
.Include(x => x.ResultDescriptions)
.Include(x => x.QuizPasswords)
.Take(20)
.ToList();
但如果我去掉 QuizPasswords 就可以了：
var usersQuizzes = this.Context.EntitySet<Quiz>()
.Include(x => x.QuizVersions)
.Include(x => x.ResultDescriptions)
.Take(20)
.ToList();
错误信息
在 mscorlib.dll 中出现“System.FormatException”类型的异常 但未在用户代码中处理
附加信息：字符串未被识别为有效的布尔值。
Quiz.cs
public partial class Quiz
public Quiz()
this.TakerAnswers = new List<TakerAnswer>();
this.FeaturedQuizzes = new List<FeaturedQuiz>();
this.PersonalityOutcomes = new List<PersonalityOutcome>();
this.PossibleAnswers = new List<PossibleAnswer>();
this.Questions = new List<Question>();
this.QuizLinks = new List<QuizLink>();
this.QuizPasswords = new List<QuizPassword>();
this.QuizSubmissions = new List<QuizSubmission>();
this.QuizVersions = new List<QuizVersion>();
this.ResultDescriptions = new List<ResultDescription>();
this.Takers = new List<Taker>();
this.PersonalityResultImages = new List<PersonalityResultImage>();
this.PersonalityShareImages = new List<PersonalityShareImage>();
public int Id get; set;
public int UserId get; set;
public Nullable<int> QuizVersionId get; set;
public string IpAddress get; set;
[DefaultValue(false)]
public bool IsPublic get; set;
[DefaultValue(QuizType.Scored)]
public QuizType QuizType get; set;
public int CreatedTime get; set;
public Nullable<int> BackgroundId get; set;
[Index(IsUnique = true)]
public string UrlId get; set;
[DefaultValue(false)]
public bool PasswordsDisabled get; set;
[DefaultValue(false)]
public bool SharedFacebook get; set;
[DefaultValue(false)]
public bool SharedTwitter get; set;
[DefaultValue(false)]
public bool Deleted get; set;
[DefaultValue(false)]
public bool ShowCorrections get; set;
[DefaultValue(true)]
public bool ShowBreakdown get; set;
public string Thumbnail get; set;
public string ShareImage get; set;
public Nullable<int> QuizLinkId get; set;
[DefaultValue(false)]
public bool ForceShareImage get; set;
[DefaultValue(0)]
public int ShareCount get; set;
[DefaultValue(BackgroundAlign.Top)]
public BackgroundAlign BackgroundAlign get; set;
public string BackgroundColour get; set;
public string TextColour get; set;
public virtual ICollection<TakerAnswer> TakerAnswers get; set;
public virtual ICollection<FeaturedQuiz> FeaturedQuizzes get; set;
public virtual ICollection<PersonalityOutcome> PersonalityOutcomes get; set;
public virtual ICollection<PossibleAnswer> PossibleAnswers get; set;
public virtual ICollection<Question> Questions get; set;
public virtual ICollection<QuizLink> QuizLinks get; set;
public virtual ICollection<QuizPassword> QuizPasswords get; set;
public virtual ICollection<QuizSubmission> QuizSubmissions get; set;
public virtual ICollection<QuizVersion> QuizVersions get; set;
public virtual QuizBackground QuizBackground get; set;
public virtual QuizLink QuizLink get; set;
public virtual QuizVersion QuizVersion get; set;
public virtual User User get; set;
public virtual ICollection<ResultDescription> ResultDescriptions get; set;
public virtual ICollection<Taker> Takers get; set;
public virtual ICollection<PersonalityResultImage> PersonalityResultImages get; set;
public virtual ICollection<PersonalityShareImage> PersonalityShareImages get; set;
QuizVersion.cs
public partial class QuizVersion
public QuizVersion()
this.TakerAnswers = new List<TakerAnswer>();
this.FeaturedQuizzes = new List<FeaturedQuiz>();
this.PersonalityOutcomes = new List<PersonalityOutcome>();
this.PossibleAnswers = new List<PossibleAnswer>();
this.Questions = new List<Question>();
this.QuizSubmissions = new List<QuizSubmission>();
this.Takers = new List<Taker>();
public int Id get; set;
public int QuizId get; set;
public string QuizName get; set;
public string QuizIntro get; set;
public string IpAddress get; set;
public bool Public get; set;
public int CreatedTime get; set;
public virtual ICollection<TakerAnswer> TakerAnswers get; set;
public virtual ICollection<FeaturedQuiz> FeaturedQuizzes get; set;
public virtual ICollection<PersonalityOutcome> PersonalityOutcomes get; set;
public virtual ICollection<PossibleAnswer> PossibleAnswers get; set;
public virtual ICollection<Question> Questions get; set;
public virtual Quiz Quiz get; set;
public virtual ICollection<QuizSubmission> QuizSubmissions get; set;
public virtual ICollection<Taker> Takers get; set;
ResultDescription.cs
public partial class ResultDescription
public int Id get; set;
public int QuizId get; set;
public Nullable<int> Percentage get; set;
public string Description get; set;
[DefaultValue(false)]
public bool Deleted get; set;
public virtual Quiz Quiz get; set;
我认为这可能是我的数据库中的一些可疑值，但我检查了我的 POCO 类中的所有 bool 类型值，它们似乎都是类型 tinyint(1) 并设置为 1 或0 并且没有空值。
什么可能导致这个错误？
【问题讨论】：
【参考方案1】：在您的第一个错误示例中，我遇到了同样的问题并使用了此解决方法：
var usersQuizzes = this.Context.EntitySet<Quiz>()
.Include(x => x.Questions)
.Include(x => x.QuizVersion)
.Include(x => x.QuizPasswords)
.Include(x => x.QuizVersion.Questions);
this.Context.Entry(userQuizes).Collection("QuizVersions").Load();
userQuizes.Take(20).ToList();
【讨论】：
它可以工作，虽然没有人们希望的那么高效。最好添加错误报告以供历史参考。 bugs.mysql.com/bug.php?id=68886, bugs.mysql.com/bug.php?id=76466【参考方案2】：我已经设法通过切换包含顺序并将有问题的包含放在第一位（在您的情况下是 x.QuizPasswords）来使我的代码工作
【讨论】：
【参考方案3】：我找到了一个解决方案，强制属性“位”默认为“假”。我更改了 Mysql 中的数据类型。 Tinyint -> 位。
[Column("Active", TypeName = "bit")]
[DefaultValue(false)]
public bool Active get; set;
链接参考：
Entity Framework MySQL tinyint(1) System.Boolean.Parse FormatException
【讨论】：
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