ObjectDataSourceStatusEventArgs.Exception Property
Definition
Important
Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
Gets a wrapper for any exceptions that are thrown by the method that is called by the ObjectDataSource control during a data operation.
public:
property Exception ^ Exception { Exception ^ get(); };public Exception Exception { get; }member this.Exception : ExceptionPublic ReadOnly Property Exception As ExceptionProperty Value
An Exception that wraps any exceptions thrown by the business object in its InnerException.
Examples
The following code example demonstrates how to use an ObjectDataSource control with a business object and a GridView control to delete data. The GridView initially displays a set of all employees, using the method that is specified by the SelectMethod property to retrieve the data from the EmployeeLogic object. Because the AutoGenerateDeleteButton property is set to true, the GridView control automatically displays a Delete button.
If you click the Delete button, the Delete action is performed using the method that is specified by the DeleteMethod property and any parameters that are specified in the DeleteParameters collection.
In this code example, some preprocessing and post-processing steps are also performed. The NorthwindEmployeeDeleting delegate is called to handle the Deleting event before the Delete action is performed, and the NorthwindEmployeeDeleted delegate is called to handle the Deleted event after the Delete action has completed, to perform any exception handling. In this example, if a NorthwindDataException is thrown, it is handled by the NorthwindEmployeeDeleted delegate.
To examine the implementation of the EmployeeLogic middle-tier business object that this code example uses, see the class overview in ObjectDataSourceStatusEventArgs.
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.CS" Assembly="Samples.AspNet.CS" %>
<%@ Import namespace="Samples.AspNet.CS" %>
<%@ 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">
private void NorthwindEmployeeDeleting(object source, ObjectDataSourceMethodEventArgs e)
{
// The GridView passes the ID of the employee
// to be deleted. However, the buisiness object, EmployeeLogic,
// requires a NorthwindEmployee parameter, named "ne". Create
// it now and add it to the parameters collection.
IDictionary paramsFromPage = e.InputParameters;
if (paramsFromPage["EmpID"] != null) {
NorthwindEmployee ne
= new NorthwindEmployee( Int32.Parse(paramsFromPage["EmpID"].ToString()));
// Remove the old EmpID parameter.
paramsFromPage.Clear();
paramsFromPage.Add("ne", ne);
}
}
private void NorthwindEmployeeDeleted(object source, ObjectDataSourceStatusEventArgs e)
{
// Handle the Exception if it is a NorthwindDataException
if (e.Exception != null)
{
// Handle the specific exception type. The ObjectDataSource wraps
// any Exceptions in a TargetInvokationException wrapper, so
// check the InnerException property for expected Exception types.
if (e.Exception.InnerException is NorthwindDataException)
{
Label1.Text = e.Exception.InnerException.Message;
// Because the exception is handled, there is
// no reason to throw it.
e.ExceptionHandled = true;
}
}
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>ObjectDataSource - C# Example</title>
</head>
<body>
<form id="Form1" method="post" runat="server">
<asp:gridview
id="GridView1"
runat="server"
datasourceid="ObjectDataSource1"
autogeneratedeletebutton="true"
autogeneratecolumns="false"
datakeynames="EmpID">
<columns>
<asp:boundfield headertext="EmpID" datafield="EmpID" />
<asp:boundfield headertext="First Name" datafield="FirstName" />
<asp:boundfield headertext="Last Name" datafield="LastName" />
</columns>
</asp:gridview>
<asp:objectdatasource
id="ObjectDataSource1"
runat="server"
selectmethod="GetAllEmployees"
deletemethod="DeleteEmployee"
ondeleting="NorthwindEmployeeDeleting"
ondeleted="NorthwindEmployeeDeleted"
typename="Samples.AspNet.CS.EmployeeLogic">
<deleteparameters>
<asp:parameter name="EmpID" type="Int32" />
</deleteparameters>
</asp:objectdatasource>
<asp:label id="Label1" runat="server" />
</form>
</body>
</html>
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.VB" Assembly="Samples.AspNet.VB" %>
<%@ Import namespace="Samples.AspNet.VB" %>
<%@ 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">
' Called before a Delete operation.
Private Sub NorthwindEmployeeDeleting(ByVal source As Object, ByVal e As ObjectDataSourceMethodEventArgs)
' The GridView passes the ID of the employee
' to be deleted. However, the business object, EmployeeLogic,
' requires a NorthwindEmployee parameter, named "ne". Create
' it now and add it to the parameters collection.
Dim paramsFromPage As IDictionary = e.InputParameters
If Not paramsFromPage("EmpID") Is Nothing Then
Dim ne As New NorthwindEmployee(paramsFromPage("EmpID").ToString())
' Remove the old EmpID parameter.
paramsFromPage.Clear()
paramsFromPage.Add("ne", ne)
End If
End Sub ' NorthwindEmployeeDeleting
' Called after a Delete operation.
Private Sub NorthwindEmployeeDeleted(ByVal source As Object, ByVal e As ObjectDataSourceStatusEventArgs)
' Handle the Exception if it is a NorthwindDataException.
If Not e.Exception Is Nothing Then
' Handle the specific exception type. The ObjectDataSource wraps
' any Exceptions in a TargetInvokationException wrapper, so
' check the InnerException property for the expected Exception types.
If e.Exception.InnerException.GetType().Equals(GetType(NorthwindDataException)) Then
Label1.Text = e.Exception.InnerException.Message
' Because the exception is handled, there is
' no reason to throw it.
e.ExceptionHandled = True
End If
End If
End Sub ' NorthwindEmployeeDeleted
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>ObjectDataSource - VB Example</title>
</head>
<body>
<form id="Form1" method="post" runat="server">
<asp:gridview
id="GridView1"
runat="server"
datasourceid="ObjectDataSource1"
autogeneratedeletebutton="true"
autogeneratecolumns="false"
datakeynames="EmpID">
<columns>
<asp:boundfield headertext="EmpID" datafield="EmpID" />
<asp:boundfield headertext="First Name" datafield="FirstName" />
<asp:boundfield headertext="Last Name" datafield="LastName" />
</columns>
</asp:gridview>
<asp:objectdatasource
id="ObjectDataSource1"
runat="server"
selectmethod="GetAllEmployees"
deletemethod="DeleteEmployee"
ondeleting="NorthwindEmployeeDeleting"
ondeleted="NorthwindEmployeeDeleted"
typename="Samples.AspNet.VB.EmployeeLogic">
<deleteparameters>
<asp:parameter name="EmpID" type="Int32" />
</deleteparameters>
</asp:objectdatasource>
<asp:label id="Label1" runat="server" />
</form>
</body>
</html>
Remarks
The Exception exception does not represent the actual exception that is thrown by the business object data method. You can use the InnerException property to access the thrown exception.
