Question

有一点背景，我是一名正在开发他的第一个Winform的网页开发人员。

我正在使用EF5。这些表是关系表，但表只有一个主键。我有一个Winform附加GridView。此GridView由BindingSource填充。 Linq查询正在填充Datasource的{{1}}。

BindingSource

我的问题是Public Class Form1 Private batchEnt As BatchMananger.PrintManagerEntities Private Sub Form1_Load(sender As Object, e As EventArgs) Handles Me.Load Try batchEnt = New BatchMananger.PrintManagerEntities batchBindingSource.DataSource = (From b In batchEnt.AutomatedBatches Join bd In batchEnt.AutomatedBatchResults On b.ID Equals bd.AutomatedBatchID Where b.BatchName <> "" Select b.ID, b.BatchName, b.Description, b.ScheduleDesc, b.BatchResultEmail, b.BatchSourceEmail, bd.ExecutionDateTime, bd.TotalSuccesful, bd.TotalItems, bd.TotalFail).ToList Catch ex As Exception Throw End Try End Sub End Class只填充了Gridview表中的数据，而不是来自联接表AutomatedBatches的数据。但是，在检查AutomatedBatchResults元素时，我发现联接的结果正在返回。我将如何绑定到Datasource，以便BIndingsource查询的所有结果都填充我的Linq。

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的更新

发现了什么问题。我没有在GridView的属性上设置DataPropertyName。将DataPropertyName设置为与其工作的数据库字段相同的名称。我还在EF数据模型中创建了AutomatedBatch（1）与AutomatedBatchResult（很多）之间的关联。

Answer 1

如果没有看到您的数据，那么您的加入请求会导致联接表中的某些记录无法显示。请记住，linq中的join关键字是内连接，因此不会显示任何不符合连接条件的记录。要显示表格中的所有记录，请执行以下操作：

快速注意 - 请在所有对象上添加类型。

Private batchEnt As BatchMananger.PrintManagerEntities
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles Me.Load

        Try
            Dim batchEnt As PrintManagerEntities = New PrintManagerEntities
            Dim batchBindingSource

            Dim batcheswithResults = (From b In batchEnt.AutomatedBatches
                                             Join bd In batchEnt.AutomatedBatchResults  On b.ID Equals bd.AutomatedBatchID
                                             Where b.BatchName <> ""
                                             Select New Results(b, bd)).ToList

            Dim batchesWithoutResults = (From b In batchEnt.AutomatedBatches
                                         Where Not batchEnt.AutomatedBatchResults.Any(Function(o) o.Id = b.Id)
                                         Select New Results(b, Nothing)).ToList

            Dim itemsSource As New List(Of Object)
            itemsSource.AddRange(batcheswithResults)
            itemsSource.AddRange(batchesWithoutResults)

            batchBindingSource.DataSource = itemsSource

        Catch ex As Exception
            Throw
        End Try
    End Sub

End Module

Public Class Results
    'TODO: Add types to params and all properties
    Public Sub New(AutomaticBatches, AutomatedBatchResults)
        _automaticBatches = AutomaticBatches
        _automatedBatchResults = AutomatedBatchResults
    End Sub

    Private _automaticBatches
    Private _automatedBatchResults

    Public Property ID
        Get
            Return _automaticBatches.ID
        End Get
        Set(value)
            _automaticBatches.ID = value
        End Set
    End Property
    Public Property BatchName
        Get
            Return _automaticBatches.BatchName
        End Get
        Set(value)
            _automaticBatches.BatchName = value
        End Set
    End Property
    Public Property Description
        Get
            Return _automaticBatches.Description
        End Get
        Set(value)
            _automaticBatches.Description = value
        End Set
    End Property
    Public Property ScheduleDesc
        Get
            Return _automaticBatches.ScheduleDesc
        End Get
        Set(value)
            _automaticBatches.ScheduleDesc = value
        End Set
    End Property
    Public Property BatchResultEmail
        Get
            Return _automaticBatches.BatchResultEmail
        End Get
        Set(value)
            _automaticBatches.BatchResultEmail = value
        End Set
    End Property
    Public Property BatchSourceEmail
        Get
            Return _automaticBatches.BatchSourceEmail
        End Get
        Set(value)
            _automaticBatches.BatchSourceEmail = value
        End Set
    End Property
    Public Property ExecutionDateTime
        Get
            If _automatedBatchResults IsNot Nothing Then Return _automatedBatchResults.ExecutionDateTime
            Return Nothing
        End Get
        Set(value)
            If _automatedBatchResults IsNot Nothing Then _automatedBatchResults.ExecutionDateTime = value
        End Set
    End Property
    Public Property TotalSuccesful
        Get
            If _automatedBatchResults IsNot Nothing Then Return _automatedBatchResults.TotalSuccesful
            Return Nothing
        End Get
        Set(value)
            If _automatedBatchResults IsNot Nothing Then _automatedBatchResults.TotalSuccesful = value
        End Set
    End Property
    Public Property TotalItems
        Get
            If _automatedBatchResults IsNot Nothing Then Return _automatedBatchResults.TotalItems
            Return Nothing
        End Get
        Set(value)
            If _automatedBatchResults IsNot Nothing Then _automatedBatchResults.TotalItems = value
        End Set
    End Property
    Public Property TotalFail
        Get
            If _automatedBatchResults IsNot Nothing Then Return _automatedBatchResults.TotalFail
            Return Nothing
        End Get
        Set(value)
            If _automatedBatchResults IsNot Nothing Then _automatedBatchResults.TotalFail = value
        End Set
    End Property

End Class

Answer 2

发现了什么问题。我没有在GridView的属性上设置DataPropertyName。将DataPropertyName设置为与其工作的数据库字段相同的名称。我还在EF数据模型中创建了AutomatedBatch（1）与AutomatedBatchResult（很多）之间的关联。

没有返回所有数据

的更新

2 个答案: