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如何确定SaveChanges失败的实体

entity-framework-4

Ralph Shillington · 技术社区 · 14 年前

调用SaveChanges时,我的对象上下文中有许多挂起的更改。其中某个实体的某个列的值太长。这将导致SqlException:字符串或二进制数据将被截断。

问题是如何确定违规实体/列?

2 回复 | 直到 14 年前

Chase Florell 14 年前

你可以考虑使用 DataAnnotations 以及构建好友类进行验证。如果用户的数据不正确,则向用户显示友好的验证错误。

Imports System.ComponentModel.DataAnnotations 

Namespace Domain 
#Region "Validation" 

<MetadataType(GetType(UserMetaData))> _ 
Partial Public Class User 
End Class 


''' <summary> 
''' Validation for all User data. 
''' </summary> 
''' <remarks>All validation is done at the Service Layer</remarks> 
Public Class UserMetaData 

    <DisplayName("name")> _ 
    <Required(ErrorMessage:="Username is required.")> _ 
    <StringLength(30, ErrorMessage:="Username cannot exceed 30 characters.")> _ 
    <RegularExpression("^\w{3,30}$", ErrorMessage:="Not a valid username.")> _ 
    Public Property UserName As String 

    <DisplayName("email")> _ 
    <StringLength(50, ErrorMessage:="Email Address cannot exceed 50 characters.")> _ 
    <RegularExpression("^([a-zA-Z0-9_\-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([a-zA-Z0-9\-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})$", ErrorMessage:="Not a valid email address.")> _ 
    Public Property Email As String 

    <DisplayName("website")> _ 
    <StringLength(256, ErrorMessage:="Web Address cannot exceed 256 characters.")> _ 
    <RegularExpression("^http(s?)\://[a-zA-Z0-9\-\.]+\.[a-zA-Z]{2,3}(/\S*)?$", ErrorMessage:="Not a valid website address.")> _ 
    Public Property WebSite As String 

    <DisplayName("about")> _ 
    <StringLength(2000, ErrorMessage:="Profile cannot exceed 2000 characters.")> _ 
    Public Property About As String 

    <DisplayName("region")> _ 
    <Required(ErrorMessage:="Region is required.")> _ 
    Public Property UserRegion As Integer 

    <DisplayName("birthdate")> _ 
    <DisplayFormat(ApplyFormatInEditMode:=True, ConvertEmptyStringToNull:=True, DataFormatString:="{0:MM/dd/yyyy}")> _ 
    Public Property BirthDate As DateTime 

End Class 
#End Region 
End Namespace