Gets or sets the name of the method or function that the ObjectDataSource control invokes to insert data.
Assembly: System.Web (in System.Web.dll)
The business object is assumed to insert data one record at a time, rather than in a batch.
The method that is identified by the property can be an instance method or a static (Shared in Visual Basic) method. If it is an instance method, the business object is created and destroyed each time the method specified by the property is called. You can handle the ObjectCreated and ObjectCreating events to work with the business object before the property is called. You can also handle the ObjectDisposing event that is raised after the method that is specified by the DeleteMethod property is called. If the business object implements the IDisposable interface, the Dispose method is called before the object is destroyed. If the method is static (Shared in Visual Basic), the business object is never created and you cannot handle the ObjectCreated, ObjectCreating, and ObjectDisposing events.
Parameters are added to the InsertParameters collection from three sources:
From the data-bound control, at run time.
From the InsertParameters element, declaratively.
From the Inserting method, programmatically.
First, any parameters that are generated from data-bound controls are added to the InsertParameters collection. For example, if the ObjectDataSource control is bound to a GridView control that has the columns Name and Number, the parameters for Name and Number are added to the collection. The data type of these parameters is string. Next, the parameters that are listed in the InsertParameters element are added. If a parameter in the InsertParameters element is found with the same name as a parameter that is already in the InsertParameters collection, the existing parameter is modified to match the parameter that is specified in the InsertParameters element. Typically, this is used to modify the type of the data in the parameter. Finally, you can programmatically add and remove parameters in the Inserting event, which occurs before the Insert method is run. The method is resolved after the parameters are merged. Method resolution is discussed in the next section.
You should validate any parameter value that you receive from the client. The runtime simply substitutes the parameter value into the property.
When the Insert method is called, the data fields from the data-bound control, the parameters that were created declaratively in the InsertParameters element, and the parameters that were added in the Inserting event handler are all merged. (For more information, see the preceding section.) The ObjectDataSource object then attempts to find a method to call. First, it looks for one or more methods with the name that is specified in the property. If no match is found, an InvalidOperationException exception is thrown. If a match is found, it then looks for matching parameter names. For example, suppose a type that is specified by the TypeName property has two methods named InsertARecord. One InsertARecord has one parameter, ID, and the other InsertARecord has two parameters, Name and Number. If the InsertParameters collection has only one parameter named ID, the InsertARecord method with just the ID parameter is called. The type of the parameter is not checked in resolving the methods. The order of the parameters does not matter.
If the DataObjectTypeName property is set, the method is resolved in a different way. The ObjectDataSource looks for a method with the name that is specified in the property that takes one parameter of the type that is specified in the DataObjectTypeName property. In this case, the name of the parameter does not matter.
This section contains two code examples. The first code example demonstrates how to use an ObjectDataSource object with a business object and a DetailsView control to insert data. The second code example provides an example of the middle-tier business object that is used in the first code example.
The following code example demonstrates how to use an ObjectDataSource control with a business object and a DetailsView control to insert data. Initially, the DetailsView displays a new NorthwindEmployee record, along with an automatically generated Insert button. After you enter data into the fields of the DetailsView control, click the Insert button. The property identifies which method performs the insert operation.
In this example, the UpdateEmployeeInfo method is used to perform an insert; however, it requires a NorthwindEmployee parameter to insert the data. For this reason, the collection of strings that the DetailsView control passes automatically is not sufficient. The NorthwindEmployeeInserting delegate is an ObjectDataSourceMethodEventHandler object that handles the Inserting event and enables you to manipulate the input parameters before the Insert operation proceeds. Because the UpdateEmployeeInfo method requires a NorthwindEmployee object as a parameter, one is created using the collection of strings and is added to the InputParameters collection using a parameter name (ne) that the method expects. You might perform steps like these when using an existing middle-tier object as a data source with types and methods that are not designed specifically for use with the ObjectDataSource control.
When the Insert operation is performed, the method that is identified by the property is called. If the Insert method of the object has a method signature that includes parameters, the InsertParameters collection must contain a parameter with names that match the method signature parameters for the Insert method to complete successfully.
<%@ 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"> Private Sub NorthwindEmployeeInserting(source As Object, e As ObjectDataSourceMethodEventArgs) ' The GridView control passes an array of strings in the parameters ' collection because that is the type it knows how to work with. ' However, the business object expects a custom type. Build it ' and add it to the parameters collection. Dim paramsFromPage As IDictionary = e.InputParameters Dim ne As New NorthwindEmployee() ne.FirstName = paramsFromPage("FirstName").ToString() ne.LastName = paramsFromPage("LastName").ToString() ne.Title = paramsFromPage("Title").ToString() ne.Courtesy = paramsFromPage("Courtesy").ToString() ne.Supervisor = Int32.Parse(paramsFromPage("Supervisor").ToString()) paramsFromPage.Clear() paramsFromPage.Add("ne", ne) End Sub ' NorthwindEmployeeInserting </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:detailsview id="DetailsView1" runat="server" autogenerateinsertbutton="True" datasourceid="ObjectDataSource1"> </asp:detailsview> <asp:objectdatasource id="ObjectDataSource1" runat="server" selectmethod="GetEmployee" insertmethod="UpdateEmployeeInfo" oninserting="NorthwindEmployeeInserting" typename="Samples.AspNet.VB.EmployeeLogic" > <selectparameters> <asp:parameter name="anID" defaultvalue="-1" /> </selectparameters> </asp:objectdatasource> </form> </body> </html>
The following code example provides an example of a middle-tier business object that the preceding code example uses. The code example consists of two basic classes:
The EmployeeLogic class, which is a stateless class that encapsulates business logic.
The NorthwindEmployee class, which is a model class that contains only the basic functionality that is required to load and persist data from the data tier.
An additional NorthwindDataException class is provided as a convenience. For a complete working example, you must compile and use these classes. The UpdateEmployeeInfo method is not completely implemented, so you will not insert data into the Northwind Traders database when you experiment with this example.
Imports System Imports System.Collections Imports System.Configuration Imports System.Data Imports System.Data.SqlClient Imports System.Web.UI Imports System.Web.UI.WebControls Namespace Samples.AspNet.VB ' ' EmployeeLogic is a stateless business object that encapsulates ' the operations you can perform on a NorthwindEmployee object. ' Public Class EmployeeLogic ' Returns a collection of NorthwindEmployee objects. Public Shared Function GetAllEmployees() As ICollection Dim al As New ArrayList() Dim cts As ConnectionStringSettings = ConfigurationManager.ConnectionStrings("NorthwindConnection") Dim sds As New SqlDataSource(cts.ConnectionString, "SELECT EmployeeID FROM Employees") Try Dim IDs As IEnumerable = sds.Select(DataSourceSelectArguments.Empty) ' Iterate through the Enumeration and create a ' NorthwindEmployee object for each ID. Dim enumerator As IEnumerator = IDs.GetEnumerator() While enumerator.MoveNext() ' The IEnumerable contains DataRowView objects. Dim row As DataRowView = CType(enumerator.Current,DataRowView) Dim id As String = row("EmployeeID").ToString() Dim nwe As New NorthwindEmployee(id) ' Add the NorthwindEmployee object to the collection. al.Add(nwe) End While Finally ' If anything strange happens, clean up. sds.Dispose() End Try Return al End Function 'GetAllEmployees Public Shared Function GetEmployee(anID As Object) As NorthwindEmployee If anID.Equals("-1") OrElse anID.Equals(DBNull.Value) Then Return New NorthwindEmployee() Else Return New NorthwindEmployee(anID) End If End Function 'GetEmployee Public Shared Sub UpdateEmployeeInfo(ne As NorthwindEmployee) Dim retval As Boolean = ne.Save() If Not retval Then Throw New NorthwindDataException("UpdateEmployee failed.") End If End Sub 'UpdateEmployeeInfo Public Shared Sub DeleteEmployee(ne As NorthwindEmployee) Dim retval As Boolean = ne.Delete() If Not retval Then Throw New NorthwindDataException("DeleteEmployee failed.") End If End Sub 'DeleteEmployee ' And so on... End Class 'EmployeeLogic Public Class NorthwindEmployee Public Sub New() ID = DBNull.Value lastName = "" firstName = "" title = "" titleOfCourtesy = "" reportsTo = - 1 End Sub 'New Public Sub New(anID As Object) Me.ID = anID Dim cts As ConnectionStringSettings = ConfigurationManager.ConnectionStrings("NorthwindConnection") Dim conn As New SqlConnection(cts.ConnectionString) Dim sc As New SqlCommand(" SELECT FirstName,LastName,Title,TitleOfCourtesy,ReportsTo " & _ " FROM Employees " & _ " WHERE EmployeeID = @empId", conn) ' Add the employee ID parameter and set its value. sc.Parameters.Add(New SqlParameter("@empId", SqlDbType.Int)).Value = Int32.Parse(anID.ToString()) Dim sdr As SqlDataReader = Nothing Try conn.Open() sdr = sc.ExecuteReader() ' Only loop once. If Not (sdr Is Nothing) AndAlso sdr.Read() Then ' The IEnumerable contains DataRowView objects. Me.aFirstName = sdr("FirstName").ToString() Me.aLastName = sdr("LastName").ToString() Me.aTitle = sdr("Title").ToString() Me.titleOfCourtesy = sdr("TitleOfCourtesy").ToString() If Not sdr.IsDBNull(4) Then Me.reportsTo = sdr.GetInt32(4) End If Else Throw New NorthwindDataException("Data not loaded for employee id.") End If Finally Try If Not (sdr Is Nothing) Then sdr.Close() End If conn.Close() Catch se As SqlException ' Log an event in the Application Event Log. Throw End Try End Try End Sub 'New Private ID As Object Public ReadOnly Property EmpID() As String Get Return ID.ToString() End Get End Property Private aLastName As String Public Property LastName() As String Get Return aLastName End Get Set aLastName = value End Set End Property Private aFirstName As String Public Property FirstName() As String Get Return aFirstName End Get Set aFirstName = value End Set End Property Public ReadOnly Property FullName() As String Get Return FirstName & " " & LastName End Get End Property Private aTitle As String Public Property Title() As String Get Return aTitle End Get Set aTitle = value End Set End Property Private titleOfCourtesy As String Public Property Courtesy() As String Get Return titleOfCourtesy End Get Set titleOfCourtesy = value End Set End Property Private reportsTo As Integer Public Property Supervisor() As Integer Get Return reportsTo End Get Set reportsTo = value End Set End Property Public Function Save() As Boolean ' Implement persistence logic. Return True End Function 'Save Public Function Delete() As Boolean ' Implement delete logic. Return True End Function 'Delete End Class 'NorthwindEmployee Friend Class NorthwindDataException Inherits Exception Public Sub New(msg As String) MyBase.New(msg) End Sub 'New End Class 'NorthwindDataException End Namespace