LinqDataSourceUpdateEventArgs Class
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LinqDataSourceUpdateEventArgs Class

.NET Framework (current version)
 

Provides data for the Updating event.

Namespace:   System.Web.UI.WebControls
Assembly:  System.Web.Extensions (in System.Web.Extensions.dll)

System.Object
  System.EventArgs
    System.ComponentModel.CancelEventArgs
      System.Web.UI.WebControls.LinqDataSourceUpdateEventArgs

public class LinqDataSourceUpdateEventArgs : CancelEventArgs

NameDescription
System_CAPS_pubmethodLinqDataSourceUpdateEventArgs(LinqDataSourceValidationException)

Initializes a new instance of the LinqDataSourceUpdateEventArgs class with the specified exception.

System_CAPS_pubmethodLinqDataSourceUpdateEventArgs(Object, Object)

Initializes a new instance of the LinqDataSourceUpdateEventArgs class.

NameDescription
System_CAPS_pubpropertyCancel

Gets or sets a value indicating whether the event should be canceled.(Inherited from CancelEventArgs.)

System_CAPS_pubpropertyException

Gets the exception that was thrown while the data was being validated before the update operation.

System_CAPS_pubpropertyExceptionHandled

Gets or sets a value that indicates whether the exception was handled and that it should not be thrown again.

System_CAPS_pubpropertyNewObject

Gets the object that contains the values that will be saved in the data source.

System_CAPS_pubpropertyOriginalObject

Gets the object that contains the values that were originally retrieved from the data source.

NameDescription
System_CAPS_pubmethodEquals(Object)

Determines whether the specified object is equal to the current object.(Inherited from Object.)

System_CAPS_protmethodFinalize()

Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.(Inherited from Object.)

System_CAPS_pubmethodGetHashCode()

Serves as the default hash function. (Inherited from Object.)

System_CAPS_pubmethodGetType()

Gets the Type of the current instance.(Inherited from Object.)

System_CAPS_protmethodMemberwiseClone()

Creates a shallow copy of the current Object.(Inherited from Object.)

System_CAPS_pubmethodToString()

Returns a string that represents the current object.(Inherited from Object.)

The LinqDataSourceUpdateEventArgs object is passed to any event handler for the Updating event. You can use the LinqDataSourceUpdateEventArgs object to examine the data before the update operation is executed in the data source. You can then validate the data, examine validation exceptions thrown by the data class, or change a value before the update. You can also cancel the update operation.

The OriginalObject object contains the data that was originally retrieved from the data source. The NewObject object contains the data that will be saved in the data source during the update operation.

If the object that represents the data source throws a validation exception before updating the data, the Exception property contains an instance of the LinqDataSourceValidationException class. You can retrieve all the validation exceptions through the InnerExceptions property. If no validation exception is thrown, the Exception property contains null. If you handle the validation exceptions and do not want the exception to be re-thrown, set the ExceptionHandled property to true.

By default, the LinqDataSource control stores the original values from the data source in view state on the Web page, except those whose ColumnAttribute attribute is marked as UpdateCheck.Never. LINQ to SQL automatically checks the integrity of the data before updating the data. It does this by comparing the current values in the data source with the original values stored in view state. LINQ to SQL raises an exception if the values in the data source have changed. You can perform additional data validation by creating a handler for the Updating event.

The following example shows an event handler for the Updating event. The example shows how to compare properties from the OriginalObject property and the NewObject property to determine whether the value in the Category property has changed. If so, the CategoryChanged property of the object in the NewObject property is set to true.

protected void LinqDataSource_Updating(object sender, LinqDataSourceUpdateEventArgs e)
{
    Product originalProduct = (Product)e.OriginalObject;
    Product newProduct = (Product)e.NewObject;

    if (originalProduct.Category != newProduct.Category)
    {
        newProduct.CategoryChanged = true;
    }
}

The following example shows an event handler for the Updating event. It displays any validation exception messages by using a Label control.

Protected Sub LinqDataSource_Updating(ByVal sender As Object, _
        ByVal e As LinqDataSourceUpdateEventArgs)
    If (e.Exception IsNot Nothing) Then
        For Each innerException As KeyValuePair(Of String, Exception) _
               In e.Exception.InnerExceptions
            Label1.Text &= innerException.Key & ": " & _
                innerException.Value.Message & "<br />"
        Next
        e.ExceptionHandled = True
    End If
End Sub

[C#]

protected void LinqDataSource_Updating(object sender, 
        LinqDataSourceUpdateEventArgs e)
{
    if (e.Exception != null)
    {
        foreach (KeyValuePair<string, Exception> innerException in 
             e.Exception.InnerExceptions)
        {
        Label1.Text += innerException.Key + ": " + 
            innerException.Value.Message + "<br />";
        }
        e.ExceptionHandled = true;
    }
}

.NET Framework
Available since 3.5

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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