Question

我遇到EF的问题，我似乎无法解决。就像标题所说，我有一对多关系。当我想从孩子那里检索父对象时，我得到Nothing（vb.net）;

对象引用未设置为对象的实例。

，而在父对象中设置了parentobjectID。

这是我到目前为止所尝试的内容：

关闭延迟装载，没有帮助。
检查外键在数据库中设置正确10次。
如果父子项的多样性，请检入edmx模型也是正确的10次。
试图通过创建上下文来欺骗部分类通过parentID检索正确的父对象。哪个给了我另一个有意义的错误;

无法定义两个对象之间的关系，因为它们附加到不同的ObjectContext对象。

我需要说这个孩子有另一个设置正确的父母。

Code Auto生成的类TestStepPageElement

Imports System
Imports System.Collections.Generic

Partial Public Class TestStepPageElement
    Public Property TestStepPageElementID As System.Guid
    Public Property PageElementID As System.Guid
    Public Property TestStepID As System.Guid
    Public Property Order As Integer

    Public Overridable Property PageElement As PageElement
    Public Overridable Property TestStep As TestStep
    Public Overridable Property TestStepPageElementParameters As ICollection(Of TestStepPageElementParameter) = New HashSet(Of TestStepPageElementParameter)

End Class

自动生成代码父

Imports System
    Imports System.Collections.Generic

    Partial Public Class PageElement
        Public Property PageElementID As System.Guid
        Public Property FriendlyName As String
        Public Property Type As TestMonkey.Shared.Enumerations.PageElementType
        Public Property PageID As System.Guid
        Public Property Description As String
        Public Property IdentifierType As TestMonkey.Shared.Enumerations.PageElementIdentifierType
        Public Property IdentifierOptions As String
        Public Property IsDeleted As Boolean

        Public Overridable Property Page As Page
        Public Overridable Property TestStepPageElements As ICollection(Of TestStepPageElement) = New HashSet(Of TestStepPageElement)

    End Class

这是TestStepPageElement的部分类，其中Me.PageElement是什么

    Partial Public Class TestStepPageElement

    ''' <summary>Converts the object to info</summary>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Public Function ToTestStepPageElementInfo() As [Shared].TestStepPageElementInfo

        Dim objInfo As New [Shared].TestStepPageElementInfo() With
            {
                .TestStepPageElementID = Me.TestStepPageElementID,
                .TestStepID = Me.TestStepID,
                .PageID = Me.PageElement.PageID,
                .PageElementID = Me.PageElementID,
                .PageElementFriendlyName = Me.PageElement.FriendlyName,
                .PageElementType = Me.PageElement.Type,
                .PageElementIdentifierType = Me.PageElement.IdentifierType,
                .PageElementIdentifierOptions = Me.PageElement.IdentifierOptions,
                .Order = Me.Order,
                .VariableNames = (From tspep In Me.TestStepPageElementParameters
                                  Order By tspep.Order
                                  Select tspep.VariableName).ToArray()
            }

        Return objInfo

    End Function

End Class

Imports System.Linq
Imports System.Text.RegularExpressions
Imports System.Text
Imports System.Reflection

这是这个部分类的名称

''' <summary></summary>
''' <remarks></remarks>
Partial Class TestStep

    ''' <summary>Converts the test step to info</summary>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Public Function ToTestStepInfo() As [Shared].TestStepInfo

        Dim objInfo As New [Shared].TestStepInfo() With
            {
                .TestStepID = Me.TestStepID,
                .FullStepText = Me.FullStepText,
                .Order = Me.Order,
                .PageID = Me.PageID,
                .ReferencedTestID = Me.ReferencedTestID,
                .ReferencedTestParameters = Me.ReferencedTestParameter.Select(Function(rtp) rtp.ToReferencedTestParameterInfo()).ToArray(),
                .Type = Me.Type,
                .TestStepSetDimensions = Me.TestStepSetDimensions.Select(Function(tssd) tssd.ToTestStepSetDimensionInfo()).ToArray(),
                .TestStepPageElements = (From tspe In Me.TestStepPageElements
                                        Order By tspe.Order
                                        Select tspe.ToTestStepPageElementInfo()).ToArray()
            }

        Return objInfo
    End Function

End Class

Answer 1

我很抱歉，我觉得很蠢。它似乎正在创建一个没有PageElement属性值的新对象。感谢您的帮助！

实体框架一对多关系父对象在子节点中为空，而父节点已设置

1 个答案: