DetailsViewUpdatedEventArgs.OldValues Propiedad
Definición
Importante
Parte de la información hace referencia a la versión preliminar del producto, que puede haberse modificado sustancialmente antes de lanzar la versión definitiva. Microsoft no otorga ninguna garantía, explícita o implícita, con respecto a la información proporcionada aquí.
Obtiene un diccionario que contiene los pares de nombre y valor originales de los campos del registro actualizado.
public:
property System::Collections::Specialized::IOrderedDictionary ^ OldValues { System::Collections::Specialized::IOrderedDictionary ^ get(); };public System.Collections.Specialized.IOrderedDictionary OldValues { get; }member this.OldValues : System.Collections.Specialized.IOrderedDictionaryPublic ReadOnly Property OldValues As IOrderedDictionaryValor de propiedad
Interfaz IOrderedDictionary que contiene un diccionario con los pares de nombre y valor originales de los campos del registro actualizado.
Ejemplos
En el ejemplo de código siguiente se muestra cómo usar la OldValues propiedad para tener acceso a los valores originales de los campos que no son clave para el registro actualizado.
<%@ Page language="C#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
void CustomerDetailsView_ItemUpdated(Object sender,
DetailsViewUpdatedEventArgs e)
{
// Use the Exception property to determine whether an exception
// occurred during the insert operation.
if (e.Exception == null)
{
// Use the Values property to get the value entered by
// the user for the CompanyName field.
String keyFieldValue = e.Keys["CustomerID"].ToString();
// Display a confirmation message.
MessageLabel.Text = "Record " + keyFieldValue +
" updated successfully. ";
// Display the old and new values.
DisplayValues(e);
if (e.AffectedRows == 1)
{
MessageLabel.Text += e.AffectedRows.ToString() +
" record updated.";
}
else
{
MessageLabel.Text += e.AffectedRows.ToString() +
" records updated.";
}
}
else
{
// Insert the code to handle the exception.
MessageLabel.Text = e.Exception.Message;
// Use the ExceptionHandled property to indicate that the
// exception is already handled.
e.ExceptionHandled = true;
// When an exception occurs, keep the DetailsView
// control in edit mode.
e.KeepInEditMode = true;
}
}
void DisplayValues(DetailsViewUpdatedEventArgs e)
{
MessageLabel.Text += "<br/></br>";
// Iterate through the OldValue and NewValues
// properties and display the values.
for (int i = 0; i < e.OldValues.Count; i++)
{
MessageLabel.Text += "Old Value=" + e.OldValues[i].ToString() +
", New Value=" + e.NewValues[i].ToString() + "<br/>";
}
MessageLabel.Text += "</br>";
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>DetailsViewUpdatedEventArgs Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>DetailsViewUpdatedEventArgs Example</h3>
<asp:detailsview id="CustomerDetailsView"
datasourceid="DetailsViewSource"
autogeneraterows="true"
autogenerateeditbutton="true"
allowpaging="true"
datakeynames="CustomerID"
onitemupdated="CustomerDetailsView_ItemUpdated"
runat="server">
<pagersettings position="Bottom"/>
</asp:detailsview>
<br/>
<asp:label id="MessageLabel"
forecolor="Red"
runat="server"/>
<!-- This example uses Microsoft SQL Server and connects -->
<!-- to the Northwind sample database. Use an ASP.NET -->
<!-- expression to retrieve the connection string value -->
<!-- from the web.config file. -->
<asp:sqldatasource id="DetailsViewSource"
selectcommand="Select [CustomerID], [CompanyName], [Address],
[City], [PostalCode], [Country] From [Customers]"
updatecommand="Update [Customers] Set
[CompanyName]=@CompanyName, [Address]=@Address,
[City]=@City, [PostalCode]=@PostalCode,
[Country]=@Country
Where [CustomerID]=@CustomerID"
connectionstring=
"<%$ ConnectionStrings:NorthWindConnectionString%>"
runat="server"/>
</form>
</body>
</html>
<%@ Page language="VB" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
Sub CustomerDetailsView_ItemUpdated(ByVal sender As Object, ByVal e As DetailsViewUpdatedEventArgs)
' Use the Exception property to determine whether an exception
' occurred during the insert operation.
If e.Exception Is Nothing Then
' Use the Values property to get the value entered by
' the user for the CompanyName field.
Dim keyFieldValue As String = e.Keys("CustomerID").ToString()
' Display a confirmation message.
MessageLabel.Text = "Record " & keyFieldValue & _
" updated successfully. "
' Display the old and new values.
DisplayValues(e)
If e.AffectedRows = 1 Then
MessageLabel.Text &= e.AffectedRows.ToString() & _
" record updated."
Else
MessageLabel.Text &= e.AffectedRows.ToString() & _
" records updated."
End If
Else
' Insert the code to handle the exception.
MessageLabel.Text = e.Exception.Message
' Use the ExceptionHandled property to indicate that the
' exception is already handled.
e.ExceptionHandled = True
' When an exception occurs, keep the DetailsView
' control in edit mode.
e.KeepInEditMode = True
End If
End Sub
Sub DisplayValues(ByVal e As DetailsViewUpdatedEventArgs)
MessageLabel.Text &= "<br/></br>"
' Iterate through the OldValue and NewValues
' properties and display the values.
Dim i As Integer
For i = 0 To e.OldValues.Count - 1
MessageLabel.Text &= "Old Value=" & e.OldValues(i).ToString() & _
", New Value=" & e.NewValues(i).ToString() & "<br/>"
Next
MessageLabel.Text &= "</br>"
End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>DetailsViewUpdatedEventArgs Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>DetailsViewUpdatedEventArgs Example</h3>
<asp:detailsview id="CustomerDetailsView"
datasourceid="DetailsViewSource"
autogeneraterows="true"
autogenerateeditbutton="true"
allowpaging="true"
datakeynames="CustomerID"
onitemupdated="CustomerDetailsView_ItemUpdated"
runat="server">
<pagersettings position="Bottom"/>
</asp:detailsview>
<br/>
<asp:label id="MessageLabel"
forecolor="Red"
runat="server"/>
<!-- This example uses Microsoft SQL Server and connects -->
<!-- to the Northwind sample database. Use an ASP.NET -->
<!-- expression to retrieve the connection string value -->
<!-- from the web.config file. -->
<asp:sqldatasource id="DetailsViewSource"
selectcommand="Select [CustomerID], [CompanyName], [Address],
[City], [PostalCode], [Country] From [Customers]"
updatecommand="Update [Customers] Set
[CompanyName]=@CompanyName, [Address]=@Address,
[City]=@City, [PostalCode]=@PostalCode,
[Country]=@Country
Where [CustomerID]=@CustomerID"
connectionstring=
"<%$ ConnectionStrings:NorthWindConnectionString%>"
runat="server"/>
</form>
</body>
</html>
Comentarios
Utilice la OldValues propiedad para tener acceso a los valores de campo originales del registro actualizado. Por ejemplo, puede usar estos valores para mantener un registro de registros actualizados.
La propiedad OldValues devuelve un objeto que implementa la interfaz IOrderedDictionary. El objeto contiene DictionaryEntry objetos que representan los campos del registro actualizado.
Nota
Como acceso directo, también puede usar el indizador del IOrderedDictionary objeto para tener acceso a los valores de campo directamente.
Se aplica a
Consulte también
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