كود مفيد (يحل مشكلة حفظ السجلات المرتبطة لأكثر من جدول) يحتاج لشرح إن أمكن

السلام عليكم

يا ليت أحد يشرح لي هذا الكود سطر سطر وأكون ممنون له :happy:

Imports System.Data.SqlServerCe

Public Class SQLCEIDHelper
    ''' <summary>
    ''' Retrieves the primary key auto-number identity values from SQL CE
    ''' </summary>
    ''' <remarks></remarks>
    Public Shared Sub SetPrimaryKey(ByVal trans As SqlCeTransaction, _
                                    ByVal e As SqlCeRowUpdatedEventArgs)

        ' If this is an INSERT operation...
        If e.Status = UpdateStatus.Continue AndAlso _
           e.StatementType = StatementType.Insert Then
            Dim pk = e.Row.Table.PrimaryKey
            ' and a primary key PK column exists...
            If pk IsNot Nothing AndAlso pk.Count = 1 Then
                'Set up the post-update query to fetch new @@Identity
                Dim cmdGetIdentity As New SqlCeCommand("SELECT @@IDENTITY", _
                                                       CType(trans.Connection, SqlCeConnection), _
                                                       trans)

                'Execute the command and set the result identity value to the PK
                e.Row(pk(0)) = CInt(cmdGetIdentity.ExecuteScalar)
                e.Row.AcceptChanges()

            End If
        End If
    End Sub
End Class

Namespace MyDatabaseDataSetTableAdapters
    Partial Public Class CategoriesTableAdapter
        Private Sub _adapter_RowUpdated(ByVal sender As Object, _
                                        ByVal e As SqlCeRowUpdatedEventArgs) _
                                        Handles _adapter.RowUpdated

            SQLCEIDHelper.SetPrimaryKey(Me.Transaction, e)
        End Sub
    End Class

    Partial Public Class ProductsTableAdapter
        Private Sub _adapter_RowUpdated(ByVal sender As Object, _
                                        ByVal e As SqlCeRowUpdatedEventArgs) _
                                        Handles _adapter.RowUpdated

            SQLCEIDHelper.SetPrimaryKey(Me.Transaction, e)
        End Sub
    End Class
End Namespace

Partial Class MyDatabaseDataSet
    Partial Class CategoriesDataTable
        Private Sub CategoriesDataTable_TableNewRow(ByVal sender As Object, _
                                            ByVal e As System.Data.DataTableNewRowEventArgs) _
                                            Handles Me.TableNewRow
            'Set defaults so that constraints don't fail when EndEdit is called
            Dim cat = CType(e.Row, CategoriesRow)
            cat.CategoryName = "[new]"
        End Sub
    End Class

    Partial Class ProductsDataTable
        Private Sub ProductsDataTable_TableNewRow(ByVal sender As Object, _
                                             ByVal e As System.Data.DataTableNewRowEventArgs) _
                                             Handles Me.TableNewRow
            'Set defaults so that constraints don't fail when EndEdit is called
            Dim product = CType(e.Row, ProductsRow)
            product.ProductName = "[new]"
        End Sub
    End Class
End Class

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