StateChangeEventArgs Classe

Definição

Fornece dados para o evento de alteração de estado de um provedor de dados .NET.Provides data for the state change event of a .NET data provider.

public ref class StateChangeEventArgs sealed : EventArgs
public sealed class StateChangeEventArgs : EventArgs
type StateChangeEventArgs = class
    inherit EventArgs
Public NotInheritable Class StateChangeEventArgs
Inherits EventArgs
Herança
StateChangeEventArgs

Exemplos

O exemplo a seguir mostra como usar o StateChange evento dentro da SqlConnection classe.The following example shows how to use the StateChange event within the SqlConnection class.

// Handler for OnStateChange event.
protected static void OnStateChange(object sender,
    StateChangeEventArgs e)
{
    PrintEventArgs(e);
}

static void Main()
{
    FillDataSet();
}

static private void FillDataSet()
{
    string connectionString = GetConnectionString();
    string queryString =
        "SELECT ProductID, UnitPrice from dbo.Products;";

    // Create a DataAdapter.
    using (SqlDataAdapter dataAdapter =
               new SqlDataAdapter(queryString, connectionString))
    {

        // Add the handlers.
        dataAdapter.SelectCommand.Connection.StateChange
            += new StateChangeEventHandler(OnStateChange);

        // Create a DataSet.
        DataSet dataSet = new DataSet();

        // Fill the DataSet, which fires several StateChange events.
        dataAdapter.Fill(dataSet, 0, 5, "Table");
    }
}

protected static void PrintEventArgs(StateChangeEventArgs args)
{
    Console.WriteLine("StateChangeEventArgs");
    Console.WriteLine("  OriginalState= {0} CurrentState= {1}",
        args.OriginalState, args.CurrentState);
}

static private string GetConnectionString()
{
    // To avoid storing the connection string in your code,
    // you can retrieve it from a configuration file.
    return "Data Source=(local);Initial Catalog=Northwind;"
        + "Integrated Security=true";
}
' Handler for the OnStateChange event.
Private Sub OnStateChange(ByVal sender As Object, _
    ByVal e As StateChangeEventArgs)
    PrintEventArgs(e)
End Sub

Sub Main()
    FillDataSet()
End Sub

Private Sub FillDataSet()
    Dim connectionString As String = GetConnectionString()
    Dim queryString As String = _
        "SELECT ProductID, UnitPrice from dbo.Products;"

    ' Create a DataAdapter.
    Using dataAdapter As New SqlDataAdapter( _
        queryString, connectionString)

        ' Add the handlers.
        AddHandler dataAdapter.SelectCommand.Connection.StateChange, _
            AddressOf OnStateChange

        ' Create a DataSet.
        Dim dataSet As New DataSet()

        ' Fill the DataSet, which fires several StateChange events.
        dataAdapter.Fill(dataSet, 0, 5, "Table")
    End Using
End Sub

Private Sub PrintEventArgs(ByVal args As StateChangeEventArgs)
    Console.WriteLine("StateChangeEventArgs")
    Console.WriteLine("  OriginalState= {0} CurrentState= {1}", _
        args.OriginalState, args.CurrentState)
End Sub

Private Function GetConnectionString() As String
    ' To avoid storing the connection string in your code,  
    ' you can retrieve it from a configuration file.
    Return "Data Source=(local);Initial Catalog=Northwind;" _
       & "Integrated Security=true;"
End Function

Comentários

Os dados são usados pela StateChange Propriedade do e pela OleDbConnection StateChange Propriedade do SqlConnection .The data is used by the StateChange property of the OleDbConnection and the StateChange property of the SqlConnection.

Construtores

StateChangeEventArgs(ConnectionState, ConnectionState)

Inicializa uma nova instância da classe StateChangeEventArgs quando são fornecidos o estado original e o estado atual do objeto.Initializes a new instance of the StateChangeEventArgs class, when given the original state and the current state of the object.

Propriedades

CurrentState

Obtém o novo estado da conexão.Gets the new state of the connection. O objeto de conexão já estará no novo estado quando o evento for acionado.The connection object will be in the new state already when the event is fired.

OriginalState

Obtém o estado original da conexão.Gets the original state of the connection.

Métodos

Equals(Object)

Determina se o objeto especificado é igual ao objeto atual.Determines whether the specified object is equal to the current object.

(Herdado de Object)
GetHashCode()

Serve como a função de hash padrão.Serves as the default hash function.

(Herdado de Object)
GetType()

Obtém o Type da instância atual.Gets the Type of the current instance.

(Herdado de Object)
MemberwiseClone()

Cria uma cópia superficial do Object atual.Creates a shallow copy of the current Object.

(Herdado de Object)
ToString()

Retorna uma cadeia de caracteres que representa o objeto atual.Returns a string that represents the current object.

(Herdado de Object)

Aplica-se a