HI
i'm using an N-tier solution. WinForm and sql server DB
The DB ha just table with ine row
The following is the DAL code
Just a Sub to create a Dataset from DB and one Sub to update DB
Note that the DAL DAL Dataset is a Public Shared Property
Imports System.Data.SqlClient
Imports Libreria
Imports System.Windows.Forms
Public Class DALAttivita
' DAL - DATA ACCESS LAYER
Private Property QueryS As String
Private Property Lastex As Exception
Private Property DALAdapter As New SqlDataAdapter
Public Shared Property DALDataset As New DataSet
Public Sub SubGetAttivita()
' testa la connessione prima di iniziare
QueryS = <sql>
SELECT
[AttivitaID]
,[RagioneSociale]
,[Indirizzo]
FROM Tabelle.[Attivita]
</sql>.Value
Using CONN As New SqlConnection With {.ConnectionString = VG.FullCS}
Using CMD As New SqlCommand With {.Connection = CONN,
.CommandType = CommandType.Text, .CommandText = QueryS}
' crea il comando SELECT
DALAdapter.SelectCommand = CMD
Dim Builder As New SqlCommandBuilder(DALAdapter)
DALAdapter.MissingSchemaAction = MissingSchemaAction.AddWithKey
DALAdapter.TableMappings.Add("Table", "Attivita")
Try
CONN.Open()
DALAdapter.Fill(DALDataset, "Attivita")
DALAdapter.Dispose()
CONN.Close()
Catch ex As Exception
MessageBox.Show("Errore lettura Achivio")
Lastex = ex
MessageBox.Show(ex.ToString)
End Try
End Using
End Using
End Sub
Public Sub SubSaveAttivita()
Using CONN As New SqlConnection With {.ConnectionString = VG.FullCS}
Using CMD As New SqlCommand With {.Connection = CONN, .CommandType =
CommandType.Text, .CommandText = QueryS}
DALAdapter.SelectCommand = CMD
Try
CONN.Open()
DALAdapter.Update(DALDataset.Tables("Attivita"))
DALAdapter.Dispose()
CONN.Close()
Catch ex As Exception
Lastex = ex
MessageBox.Show("Errore salvataggio Achivio")
MessageBox.Show(ex.ToString)
End Try
End Using
End Using
End Sub
End Class
Now the following is the BLL code
' BLL
Imports DataAccessLayer
Public Class BLLAttivita
Private Property DAL As New DALAttivita
Private Property BLLAtt As ClasseAttivita
Private Property BLLDataset As New DataSet
Private Property BLLRow As DataRow
Public Function FunGetAttivita() As ClasseAttivita
' BLLDataset = DAL.FunGetAttivita() 'prende il dataset come return
DAL.SubGetAttivita()
BLLDataset = DALAttivita.DALDataset
For Each R As DataRow In BLLDataset.Tables("Attivita").Rows
' oppure cosi ?
' For Each R As DataRow In DALAttivita.DALDataset.Tables("Attivita").Rows
BLLAtt = New ClasseAttivita With {
.AttivitaID = R(0).ToString,
.RagioneSociale = R(1),
.Indirizzo = R(2)
}
Next
Return BLLAtt
End Function
Public Sub SUBSaveAttivita(ByVal BLLAtt As ClasseAttivita)
Dim BLLTable = BLLDataset.Tables("Attivita")
BLLRow = BLLTable.Rows.Find(1)
' oppure cosi ?
' BLLRow = DALAttivita.DALDataset.Tables("Attivita").Rows.Find(1)
BLLRow.BeginEdit()
BLLRow("RagioneSociale") = BLLAtt.RagioneSociale
BLLRow("Indirizzo") = BLLAtt.Indirizzo
BLLRow.EndEdit()
DAL.SubSaveAttivita()
End Sub
End Class
Note that in BLL afte calling DAL.SubGetAttivita() I copy DALDataset to BLLDataset
Then I apply the changes from UI to BLLDataset and call DAL.SubSaveAttivita() WITHOUT passing back to DAL the BLLDataset
EVERYTHING WORKS WHEN THE DB is updated
The question is, why the DAL can get the changes made in BLLDataset if it does not get back the BLLDataset ?
