Provides data for the Updating event.
System.EventArgs
System.ComponentModel.CancelEventArgs
System.Web.UI.WebControls.LinqDataSourceUpdateEventArgs
Namespace: System.Web.UI.WebControls
Assembly: System.Web.Extensions (in System.Web.Extensions.dll)
Public Class LinqDataSourceUpdateEventArgs _ Inherits CancelEventArgs
public class LinqDataSourceUpdateEventArgs : CancelEventArgs
public ref class LinqDataSourceUpdateEventArgs : public CancelEventArgs
type LinqDataSourceUpdateEventArgs = class inherit CancelEventArgs end
The LinqDataSourceUpdateEventArgs type exposes the following members.
| Name | Description | |
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LinqDataSourceUpdateEventArgs(LinqDataSourceValidationException) | Initializes a new instance of the LinqDataSourceUpdateEventArgs class with the specified exception. |
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LinqDataSourceUpdateEventArgs(Object, Object) | Initializes a new instance of the LinqDataSourceUpdateEventArgs class. |
| Name | Description | |
|---|---|---|
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Cancel | Gets or sets a value indicating whether the event should be canceled. (Inherited from CancelEventArgs.) |
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Exception | Gets the exception that was thrown while the data was being validated before the update operation. |
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ExceptionHandled | Gets or sets a value that indicates whether the exception was handled and that it should not be thrown again. |
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NewObject | Gets the object that contains the values that will be saved in the data source. |
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OriginalObject | Gets the object that contains the values that were originally retrieved from the data source. |
| Name | Description | |
|---|---|---|
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Equals(Object) | Determines whether the specified Object is equal to the current Object. (Inherited from Object.) |
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Finalize | Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.) |
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GetHashCode | Serves as a hash function for a particular type. (Inherited from Object.) |
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GetType | Gets the Type of the current instance. (Inherited from Object.) |
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MemberwiseClone | Creates a shallow copy of the current Object. (Inherited from Object.) |
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ToString | 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 Sub LinqDataSource_Updating(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.LinqDataSourceUpdateEventArgs) Dim originalProduct As Product Dim newProduct As Product originalProduct = CType(e.OriginalObject, Product) newProduct = CType(e.NewObject, Product) If (originalProduct.Category <> newProduct.Category) Then newProduct.CategoryChanged = True End If End Sub
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
Supported in: 4, 3.5Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), 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.