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ObjectDataSourceStatusEventArgs.ExceptionHandled Property

  • Reference

Definition

Namespace:
System.Web.UI.WebControls
Assembly:
System.Web.dll

Gets or sets a value indicating whether an exception that was thrown by the business object has been handled.

C# 
public bool ExceptionHandled { get; set; }

Property Value

Boolean

true if an exception thrown by the business object has been handled and should not be thrown by the ObjectDataSource; otherwise, false.

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 handle any exceptions that might have occurred. 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.

ASP.NET (C#) 
<%@ 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>

Remarks

If the business object throws an exception, the ExceptionHandled property is set to false and the exception is wrapped by the Exception property. If you use an ObjectDataSourceStatusEventHandler object, you can check the Exception property and handle the exception. If you handle the exception, set the ExceptionHandled property to true or the ObjectDataSource control will throw an exception.

Applies to

Produkt Verzie
.NET Framework 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1

See also