作者:VB.NET开发
项目:System.Dat
Using context As New AdventureWorksEntities()
Dim entity As Object = Nothing
Dim entityKeyValues As IEnumerable(Of KeyValuePair(Of String, Object)) = _
New KeyValuePair(Of String, Object)() {New KeyValuePair(Of String, Object)("SalesOrderID", 43680)}
' Create the key for a specific SalesOrderHeader object.
Dim key As New EntityKey("AdventureWorksEntities.SalesOrderHeaders", entityKeyValues)
' Get the object from the context or the persisted store by its key.
If context.TryGetObjectByKey(key, entity) Then
Console.WriteLine("The requested " & entity.GetType().FullName & " object was found")
Else
Console.WriteLine("An object with this key could not be found.")
End If
End Using
作者:VB.NET开发
项目:System.Dat
Using context As New AdventureWorksEntities()
Try
' Create the key that represents the order.
Dim orderKey As New EntityKey("AdventureWorksEntities.SalesOrderHeaders", "SalesOrderID", orderId)
' Create the stand-in SalesOrderHeader object
' based on the specified SalesOrderID.
Dim order As New SalesOrderHeader()
order.EntityKey = orderKey
' Assign the ID to the SalesOrderID property to matche the key.
order.SalesOrderID = CInt(orderKey.EntityKeyValues(0).Value)
' Attach the stand-in SalesOrderHeader object.
context.SalesOrderHeaders.Attach(order)
' Create a new SalesOrderDetail object.
' You can use the static CreateObjectName method (the Entity Framework
' adds this method to the generated entity types) instead of the new operator:
' SalesOrderDetail.CreateSalesOrderDetail(1, 0, 2, 750, 1, (decimal)2171.2942, 0, 0,
' Guid.NewGuid(), DateTime.Today));
Dim detail = New SalesOrderDetail With
{
.SalesOrderID = 0,
.SalesOrderDetailID = 0,
.OrderQty = 2,
.ProductID = 750,
.SpecialOfferID = 1,
.UnitPrice = CDec(2171.2942),
.UnitPriceDiscount = 0,
.LineTotal = 0,
.rowguid = Guid.NewGuid(),
.ModifiedDate = DateTime.Now
}
order.SalesOrderDetails.Add(detail)
context.SaveChanges()
Catch generatedExceptionName As InvalidOperationException
Console.WriteLine("Ensure that the key value matches the value of the object's ID property.")
Catch generatedExceptionName As UpdateException
Console.WriteLine("An error has occurred. Ensure that an object with the '{0}' key value exists.", orderId)
End Try
End Using