SqlDataAdapter.SelectCommand Proprietà
Definizione
Importante
Alcune informazioni sono relative alla release non definitiva del prodotto, che potrebbe subire modifiche significative prima della release definitiva. Microsoft non riconosce alcuna garanzia, espressa o implicita, in merito alle informazioni qui fornite.
Ottiene o imposta un'istruzione Transact-SQL o una stored procedure per selezionare record nell'origine dati.
public:
property System::Data::SqlClient::SqlCommand ^ SelectCommand { System::Data::SqlClient::SqlCommand ^ get(); void set(System::Data::SqlClient::SqlCommand ^ value); };
[System.Data.DataSysDescription("DbDataAdapter_SelectCommand")]
public System.Data.SqlClient.SqlCommand SelectCommand { get; set; }
public System.Data.SqlClient.SqlCommand SelectCommand { get; set; }
[<System.Data.DataSysDescription("DbDataAdapter_SelectCommand")>]
member this.SelectCommand : System.Data.SqlClient.SqlCommand with get, set
member this.SelectCommand : System.Data.SqlClient.SqlCommand with get, set
Public Property SelectCommand As SqlCommand
Valore della proprietà
Oggetto SqlCommand utilizzato durante l'applicazione del metodo Fill(DataSet) per selezionare record nel database da collocare nell'oggetto DataSet.
- Attributi
Esempio
Nell'esempio seguente viene creato un oggetto SqlDataAdapter e vengono impostate le SelectCommandproprietà , InsertCommand, UpdateCommande DeleteCommand . Presuppone che sia già stato creato un SqlConnection oggetto .
public static SqlDataAdapter CreateCustomerAdapter(
SqlConnection connection)
{
SqlDataAdapter adapter = new SqlDataAdapter();
// Create the SelectCommand.
SqlCommand command = new SqlCommand("SELECT * FROM Customers " +
"WHERE Country = @Country AND City = @City", connection);
// Add the parameters for the SelectCommand.
command.Parameters.Add("@Country", SqlDbType.NVarChar, 15);
command.Parameters.Add("@City", SqlDbType.NVarChar, 15);
adapter.SelectCommand = command;
// Create the InsertCommand.
command = new SqlCommand(
"INSERT INTO Customers (CustomerID, CompanyName) " +
"VALUES (@CustomerID, @CompanyName)", connection);
// Add the parameters for the InsertCommand.
command.Parameters.Add("@CustomerID", SqlDbType.NChar, 5, "CustomerID");
command.Parameters.Add("@CompanyName", SqlDbType.NVarChar, 40, "CompanyName");
adapter.InsertCommand = command;
// Create the UpdateCommand.
command = new SqlCommand(
"UPDATE Customers SET CustomerID = @CustomerID, CompanyName = @CompanyName " +
"WHERE CustomerID = @oldCustomerID", connection);
// Add the parameters for the UpdateCommand.
command.Parameters.Add("@CustomerID", SqlDbType.NChar, 5, "CustomerID");
command.Parameters.Add("@CompanyName", SqlDbType.NVarChar, 40, "CompanyName");
SqlParameter parameter = command.Parameters.Add(
"@oldCustomerID", SqlDbType.NChar, 5, "CustomerID");
parameter.SourceVersion = DataRowVersion.Original;
adapter.UpdateCommand = command;
// Create the DeleteCommand.
command = new SqlCommand(
"DELETE FROM Customers WHERE CustomerID = @CustomerID", connection);
// Add the parameters for the DeleteCommand.
parameter = command.Parameters.Add(
"@CustomerID", SqlDbType.NChar, 5, "CustomerID");
parameter.SourceVersion = DataRowVersion.Original;
adapter.DeleteCommand = command;
return adapter;
}
Public Function CreateCustomerAdapter( _
ByVal connection As SqlConnection) As SqlDataAdapter
Dim adapter As SqlDataAdapter = New SqlDataAdapter()
' Create the SelectCommand.
Dim command As SqlCommand = New SqlCommand( _
"SELECT * FROM Customers " & _
"WHERE Country = @Country AND City = @City", connection)
' Add the parameters for the SelectCommand.
command.Parameters.Add("@Country", SqlDbType.NVarChar, 15)
command.Parameters.Add("@City", SqlDbType.NVarChar, 15)
adapter.SelectCommand = command
' Create the InsertCommand.
command = New SqlCommand( _
"INSERT INTO Customers (CustomerID, CompanyName) " & _
"VALUES (@CustomerID, @CompanyName)", connection)
' Add the parameters for the InsertCommand.
command.Parameters.Add("@CustomerID", SqlDbType.NChar, 5, "CustomerID")
command.Parameters.Add("@CompanyName", SqlDbType.NVarChar, 40, "CompanyName")
adapter.InsertCommand = command
' Create the UpdateCommand.
command = New SqlCommand( _
"UPDATE Customers SET CustomerID = @CustomerID, CompanyName = @CompanyName " & _
"WHERE CustomerID = @oldCustomerID", connection)
' Add the parameters for the UpdateCommand.
command.Parameters.Add("@CustomerID", SqlDbType.NChar, 5, "CustomerID")
command.Parameters.Add("@CompanyName", SqlDbType.NVarChar, 40, "CompanyName")
Dim parameter As SqlParameter = command.Parameters.Add( _
"@oldCustomerID", SqlDbType.NChar, 5, "CustomerID")
parameter.SourceVersion = DataRowVersion.Original
adapter.UpdateCommand = command
' Create the DeleteCommand.
command = New SqlCommand( _
"DELETE FROM Customers WHERE CustomerID = @CustomerID", connection)
' Add the parameters for the DeleteCommand.
command.Parameters.Add( _
"@CustomerID", SqlDbType.NChar, 5, "CustomerID")
parameter.SourceVersion = DataRowVersion.Original
adapter.DeleteCommand = command
Return adapter
End Function
Commenti
Quando SelectCommand viene assegnato a un oggetto creato SqlCommandin precedenza, l'oggetto SqlCommand non viene clonato. Mantiene SelectCommand un riferimento all'oggetto creato SqlCommand in precedenza.
Se non SelectCommand restituisce righe, non vengono aggiunte tabelle a DataSete non viene generata alcuna eccezione.