.NET Framework Class Library StateChangeEventArgs Class Provides data for the state change event of a .NET Framework data provider.
Inheritance Hierarchy
Namespace:
System.Data
Assembly:
System.Data (in System.Data.dll)
Syntax
Public NotInheritable Class StateChangeEventArgs _
Inherits EventArgs
public sealed class StateChangeEventArgs : EventArgs
public ref class StateChangeEventArgs sealed : public EventArgs
[<Sealed>]
type StateChangeEventArgs =
class
inherit EventArgs
end
The StateChangeEventArgs type exposes the following members.
Methods
Remarks
Examples
The following example shows how to use the StateChange event within the SqlConnection class.
' 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
// 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";
}
Version Information
.NET FrameworkSupported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0 .NET Framework Client ProfileSupported in: 4, 3.5 SP1
Platforms
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role not supported), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
Thread Safety
Any public static ( Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
See Also
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Biblioteca de clases de .NET Framework StateChangeEventArgs (Clase) Proporciona datos para el evento de cambio de estado de un proveedor de datos de .NET Framework.
Jerarquía de herencia
Espacio de nombres:
System.Data
Ensamblado:
System.Data (en System.Data.dll)
Sintaxis
Public NotInheritable Class StateChangeEventArgs _
Inherits EventArgs
public sealed class StateChangeEventArgs : EventArgs
public ref class StateChangeEventArgs sealed : public EventArgs
[<Sealed>]
type StateChangeEventArgs =
class
inherit EventArgs
end
El tipo StateChangeEventArgs expone los siguientes miembros.
Comentarios
Ejemplos
En el ejemplo siguiente se muestra cómo se utiliza el evento StateChange de la clase SqlConnection.
' 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
// 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";
}
Información de versión
.NET FrameworkCompatible con: 4, 3.5, 3.0, 2.0, 1.1, 1.0 .NET Framework Client ProfileCompatible con: 4, 3.5 SP1
Plataformas
Windows 7, Windows Vista SP1 o posterior, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (no se admite Server Core), Windows Server 2008 R2 (se admite Server Core con SP1 o posterior), Windows Server 2003 SP2
.NET Framework no admite todas las versiones de todas las plataformas. Para obtener una lista de las versiones compatibles, vea Requisitos de sistema de .NET Framework.
Seguridad para subprocesos
Todos los miembros static ( Shared en Visual Basic) públicos de este tipo son seguros para la ejecución de subprocesos. No se garantiza que los miembros de instancias sean seguros para la ejecución de subprocesos.
Vea también
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