Question

我是LINQ的新手，我正在尝试将Linq to SQL表绑定到几个控件（treeview，textbox等）。我希望能够更改文本框字段并轻松地将这些更新保存回数据库。

我可以使用以下方法从数据库中获取数据：

    Private LinqDB As New DataContext(My.Settings.dbConnection)
    Property tblManufacturers As Table(Of dbManufacturers) _
        = LinqDB.GetTable(Of dbManufacturers)()

将内容绑定到控件非常简单。 TreeView填充了所有的ManufacturerNames，当我点击它时，它会填充TextBoxes进行编辑问题是结果不符合我想要的树视图中的顺序我希望有类似的东西：

    Property tblManufacturers As Table(Of dbManufacturers) _
        = LinqDB.GetTable(Of dbManufacturers)().OrderBy("ManufacturerName")

会起作用，但是没有。

我知道我可以使用像

这样的东西

Dim ManufacturerQuery = From ManufacturerName In tblManufacturers Order By ManufacturerName

但是将更改推回到数据库似乎更加困难。

编辑：所以，显然我需要停止懦弱，只是尝试一下......

Namespace Controls
    Public Class ManufacturerWarranty

        Private LinqDB As New DataContext(My.Settings.dbConnection)
        Property tblManufacturers As Table(Of dbManufacturers) = LinqDB.GetTable(Of dbManufacturers)()
        Property ManufacturerQuery = From m In tblManufacturers Order By m.ManufacturerName

        Public Sub New()
            InitializeComponent()
        End Sub

        Private Sub ManufacturerWarranty_Loaded(sender As Object, e As System.Windows.RoutedEventArgs) Handles Me.Loaded
            Me.DataContext = Me
        End Sub

        Private Sub TreeView1_MouseDoubleClick(sender As System.Object, e As System.Windows.Input.MouseButtonEventArgs) Handles TreeView1.MouseDoubleClick
            StackPanel1.DataContext = e.OriginalSource.DataContext
        End Sub


        Private Sub cmdSave_Click(sender As Object, e As System.Windows.RoutedEventArgs) Handles cmdSave.Click
            LinqDB.SubmitChanges()
        End Sub
    End Class
End Namespace

然后我将TreeView绑定到ManufacturerQuery而不是tblManufacturers。我的保存按钮仍可用于提交更改，即使它们是针对ManufacturerQuery而非tblManufacturers。

Answer 1

好的，也许你想要

Dim tblManufacturers As Table(Of dbManufacturers) _
    = LinqDB.GetTable(Of dbManufacturers)() _
        .OrderBy(Function(m) m.ManufacturerName)

所以，承诺你做

Using linqDB As New DataContext(My.Settings.dbConnection)
    Dim tblManufacturers As Table(Of dbManufacturers) _
        = linqDB.GetTable(Of dbManufacturers)()

    -- change tblManufacturers.

    linqDB.SaveChanges()
End Using

我不会做的是在用户与GUI交互时保持上下文打开。同样地，除非我将数据显示给用户，否则我（可能）不会对数据进行排序。

在LINQ to SQL中使用GetTable（）。OrderBy（）的正确方法

1 个答案: