Windows窗体不会更改基础实体数据

Question

任何人都可以看到我不能做的简单错误吗？

我打开一个表单，允许将作业编号分配给没有任何发票的发票。

这是处理此问题的应用程序主窗体中的代码：

Dim unknownJobs = From pur In context.Purchases
                  Where pur.SentToMyob = False AndAlso
                        pur.Job.JobNumber = String.Empty
                  Select pur

If unknownJobs.Any Then
    frmJobs2.JobsBindingSource.DataSource = (From j In context.Jobs1
                                            Order By j.JobNumber
                                            Select j).ToList
    frmJobs2.PurchasesBindingSource.DataSource = unknownJobs
    Progress.Hide()
    If frmJobs2.ShowDialog = Windows.Forms.DialogResult.OK Then
        context.SaveChanges()
    End If
End If

这是打开的表单，其中显示了相关的列详细信息

背后的守则很简单，包括：

Public Class FormJobs2
    ''' <summary>
    ''' OK clicked
    ''' </summary>
    ''' <param name="sender"></param>
    ''' <param name="e"></param>
    ''' <remarks></remarks>
    Private Sub OKButton_Click(sender As System.Object, e As System.EventArgs) Handles OKButton.Click
        Me.DialogResult = Windows.Forms.DialogResult.OK
        Me.Close()
    End Sub

    ''' <summary>
    ''' Cancel clicked
    ''' </summary>
    ''' <param name="sender"></param>
    ''' <param name="e"></param>
    ''' <remarks></remarks>
    Private Sub SkipButton_Click(sender As System.Object, e As System.EventArgs) Handles SkipButton.Click
        Me.DialogResult = Windows.Forms.DialogResult.Cancel
        Me.Close()
    End Sub
End Class

运行时会发生的情况是您可以选择作业编号，但它们不会显示在DataGridView上，也不会更新基础上下文。

请问愚蠢的错误在哪里？

Answer 1

您似乎正在尝试为frmJobs2.PurchasesBindingSource.DataSource分配IQueryable。

该行应为：

frmJobs2.PurchasesBindingSource.DataSource = unknownJobs.ToList