IDbDataAdapter.SelectCommand Propriedade

Definição

Obtém ou define uma instrução SQL usada para selecionar registros na fonte de dados.Gets or sets an SQL statement used to select records in the data source.

public:
 property System::Data::IDbCommand ^ SelectCommand { System::Data::IDbCommand ^ get(); void set(System::Data::IDbCommand ^ value); };
public System.Data.IDbCommand? SelectCommand { get; set; }
public System.Data.IDbCommand SelectCommand { get; set; }
member this.SelectCommand : System.Data.IDbCommand with get, set
Public Property SelectCommand As IDbCommand

Valor da propriedade

IDbCommand

Um IDbCommand que é usado durante Update(DataSet) para selecionar registros da fonte de dados para posicionamento no conjunto de dados.An IDbCommand that is used during Update(DataSet) to select records from data source for placement in the data set.

Exemplos

O exemplo a seguir cria uma instância da classe herdada OleDbDataAdapter e define as SelectCommand InsertCommand Propriedades e.The following example creates an instance of the inherited OleDbDataAdapter class, and sets the SelectCommand and InsertCommand properties. Ele pressupõe que você já criou um OleDbConnection objeto.It assumes you have already created an OleDbConnection object.

public static OleDbDataAdapter CreateCustomerAdapter(
    OleDbConnection connection)
{
    OleDbDataAdapter adapter = new OleDbDataAdapter();
    OleDbCommand command;

    // Create the SelectCommand.
    command = new OleDbCommand("SELECT * FROM Customers " +
        "WHERE Country = ? AND City = ?", connection);

    command.Parameters.Add("Country", OleDbType.VarChar, 15);
    command.Parameters.Add("City", OleDbType.VarChar, 15);

    adapter.SelectCommand = command;

    // Create the InsertCommand.
    command = new OleDbCommand(
        "INSERT INTO Customers (CustomerID, CompanyName) " +
        "VALUES (?, ?)", connection);

    command.Parameters.Add(
        "CustomerID", OleDbType.Char, 5, "CustomerID");
    command.Parameters.Add(
        "CompanyName", OleDbType.VarChar, 40, "CompanyName");

    adapter.InsertCommand = command;
    return adapter;
}
Public Shared Function CreateCustomerAdapter( _
    connection As OleDbConnection) As OleDbDataAdapter 

    Dim adapter As New OleDbDataAdapter()
    Dim command As OleDbCommand

    ' Create the SelectCommand.
    command = New OleDbCommand("SELECT * FROM Customers " & _
        "WHERE Country = ? AND City = ?", connection)

    command.Parameters.Add("Country", OleDbType.VarChar, 15)
    command.Parameters.Add("City", OleDbType.VarChar, 15)

    adapter.SelectCommand = command

    ' Create the InsertCommand.
    command = New OleDbCommand( _
        "INSERT INTO Customers (CustomerID, CompanyName) " & _
        "VALUES (?, ?)", connection)

    command.Parameters.Add( _
        "CustomerID", OleDbType.Char, 5, "CustomerID")
    command.Parameters.Add( _
        "CompanyName", OleDbType.VarChar, 40, "CompanyName")

    adapter.InsertCommand = command
    Return adapter
End Function

Comentários

Quando SelectCommand é atribuído a um criado anteriormente IDbCommand , o IDbCommand não é clonado.When SelectCommand is assigned to a previously created IDbCommand, the IDbCommand is not cloned. O SelectCommand mantém uma referência ao objeto criado anteriormente IDbCommand .The SelectCommand maintains a reference to the previously created IDbCommand object.

Se o SelectCommand não retornar nenhuma linha, nenhuma tabela será adicionada ao DataSet , e nenhuma exceção será gerada.If the SelectCommand does not return any rows, no tables are added to the DataSet, and no exception is raised.

Aplica-se a