如果使用 ObjectDataSourceMethodEventHandler 对象处理 Selecting、Updating、Inserting 或 Deleting 事件，则可以使用 InputParameters 属性访问和操作这些参数。此字典中参数的任何更改都将影响到为操作所调用的方法重载。当设置了 ObjectDataSource 控件的 DataObjectTypeName 属性时，只能修改此字典中各项的数据对象属性，而不能添加或移除参数
下面的代码示例演示如何使用 DropDownList 控件、TextBox 控件和多个 ObjectDataSource 控件更新数据。DropDownList 显示一个 Northwind Employee 的名称，而 TextBox 控件用于输入和更新地址信息。由于 UpdateParameters 属性包含绑定到 DropDownList 控件的选定值的 ControlParameter 对象，因此只有在选中一个雇员后才能启用触发 Update 方法的按钮。
在此示例中，在 Update 方法之前调用 NorthwindEmployeeUpdating 方法，以便将正确的参数和值添加到 InputParameters 集合。可以通过动态方式（如演示所示）或声明方式添加参数和值。
代码
<%@ Page language="c#" %>
<%@ Import namespace="Samples.AspNet.CS" %>
<Script runat="server"> // Add parameters and initialize the user interface
// only if an employee is selected.
private void Page_Load(object sender, EventArgs e)
{
// Be sure the text boxes are initialized with
// data from the currently selected employee.
NorthwindEmployee selectedEmployee = EmployeeLogic.GetEmployee(DropDownList1.SelectedValue);
if (selectedEmployee != null) {
AddressBox.Text = selectedEmployee.Address;
CityBox.Text = selectedEmployee.City;
PostalCodeBox.Text = selectedEmployee.PostalCode;
Button1.Enabled
= true;}
else {
Button1.Enabled = false;
}
} // Press the button to update.
private void Btn_UpdateEmployee (object sender, CommandEventArgs e) {
ObjectDataSource2.Update();
} // Dynamically add parameters to the InputParameters collection.
private void NorthwindEmployeeUpdating(object source, ObjectDataSourceMethodEventArgs e) {
// The names of the parameters are the same as
// the variable names for the method that is invoked to
// perform the Update. The InputParameters collection is
// an IDictionary collection of name/value pairs,
// not a ParameterCollection.
e.InputParameters.Add("anID", DropDownList1.SelectedValue);
e.InputParameters.Add("anAddress" ,AddressBox.Text);
e.InputParameters.Add("aCity" ,CityBox.Text);
e.InputParameters.Add("aPostalCode",PostalCodeBox.Text);
}
</Script>
<html>
<head>
<title>ObjectDataSource - C# Example</title>
</head>
<body>
<form id="Form1" method="post" runat="server">
<!-- The DropDownList is bound to the first ObjectDataSource. -->
<asp:objectdatasource
id="ObjectDataSource1"
runat="server"
selectmethod="GetAllEmployees"
typename="Samples.AspNet.CS.EmployeeLogic" />
<p><asp:dropdownlist
id="DropDownList1"
runat="server"
datasourceid="ObjectDataSource1"
datatextfield="FullName"
datavaluefield="EmpID"
autopostback="True" /></p>
<!-- The second ObjectDataSource performs the Update. This
preserves the state of the DropDownList, which otherwise
would rebind when the DataSourceChanged event is
raised as a result of an Update operation. -->
<asp:objectdatasource
id="ObjectDataSource2"
runat="server"
updatemethod="UpdateEmployeeWrapper"
onupdating="NorthwindEmployeeUpdating"
typename="Samples.AspNet.CS.EmployeeLogic" />
<p><asp:textbox
id="AddressBox"
runat="server" /></p>
<p><asp:textbox
id="CityBox"
runat="server" /></p>
<p><asp:textbox
id="PostalCodeBox"
runat="server" /></p>
<asp:button
id="Button1"
runat="server"
text="Update Employee"
oncommand="Btn_UpdateEmployee" />
</form>
</body>
</html>
实例二：
本节包含两个代码示例。第一个代码示例演示如何将 ObjectDataSource 控件与业务对象和 DetailsView 控件配合使用来插入数据。第二个代码示例提供了第一个代码示例使用的中间层业务对象示例。
下面的代码示例演示如何将 ObjectDataSource 控件与业务对象和 DetailsView 控件配合使用来插入数据。DetailsView 最初显示一个新的 NorthwindEmployee 记录和一个自动生成的“插入”按钮。将数据输入 DetailsView 控件的字段中后单击“插入”按钮，InsertMethod 属性将标识出执行 Insert 操作的方法。
在此示例中，UpdateEmployeeInfo 方法用于执行插入；然而它需要 NorthwindEmployee 参数才能插入数据。因此，只有 DetailsView 控件自动传递的字符串集合并不够。NorthwindEmployeeInserting 委托是一个 ObjectDataSourceMethodEventHandler 对象，它用于处理 Inserting 事件，并使您能够在 Insert 操作继续进行之前操作输入参数。由于 UpdateEmployeeInfo 方法需要 NorthwindEmployee 对象作为参数，因此使用字符串集合创建了一个这样的对象，并将其添加到 InputParameters 集合。
代码
<%@ Import namespace="Samples.AspNet.CS" %>
<%@ Page language="c#" %>
<Script runat="server">
private void NorthwindEmployeeInserting(object source, ObjectDataSourceMethodEventArgs e)
{
// The business object expects a custom type. Build it
// and add it to the parameters collection.
IDictionary paramsFromPage = e.InputParameters;
NorthwindEmployee ne
= 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(
} </Script>
<html>
<head>
<title>ObjectDataSource - C# 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.CS.EmployeeLogic"
>
<selectparameters>
<asp:parameter name="anID" defaultvalue="-1" />
</selectparameters>
</asp:objectdatasource>
</form>
</body>
</html>
下面的代码示例提供了前一代码示例所使用的中间层业务对象的示例。下面的列表描述代码示例中定义的两个主类：
-
EmployeeLogic 类，这是封装业务逻辑的无状态类。
-
NorthwindEmployee 类，这是仅包含从数据层加载和保留数据所需的基本功能的模型类。
此外，提供 NorthwindDataException 类只是为了便于使用。
此组示例类使用 Northwind Traders 数据库，该数据库是 Microsoft SQL Server 和 Microsoft Access 自带的示例数据库。要获得完整的可运行示例，请将这些类放在应用程序根目录下的 App_Code 目录中，或者对它们进行编译并将产生的 DLL 放在 Bin 目录中，以使用这些类。UpdateEmployeeInfo 方法未完全实现，因此在试用此示例时不会将数据插入到 Northwind Traders 数据库中。
代码
using System.Collections;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
using System.Web.UI;
using System.Web.UI.WebControls;
//
// 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 static ICollection GetAllEmployees () {
ArrayList al = new ArrayList();
ConnectionStringSettings cts
= ConfigurationManager.ConnectionStrings["NorthwindConnection"]; SqlDataSource sds
"SELECT EmployeeID FROM Employees");
try {
IEnumerable IDs = sds.Select(DataSourceSelectArguments.Empty);
// Iterate through the Enumeration and create a
// NorthwindEmployee object for each ID.
IEnumerator enumerator = IDs.GetEnumerator();
while (enumerator.MoveNext()) {
// The IEnumerable contains DataRowView objects.
DataRowView row = enumerator.Current as DataRowView;
string id = row["EmployeeID"].ToString();
NorthwindEmployee nwe = new NorthwindEmployee(id);
// Add the NorthwindEmployee object to the collection.
al.Add(nwe);
}
}
finally {
// If anything strange happens, clean up.
sds.Dispose();
}
return al;
}
public static NorthwindEmployee GetEmployee(object anID) {
if (anID.Equals("-1") ||
anID.Equals(DBNull.Value) ) {
return new NorthwindEmployee();
}
else {
return new NorthwindEmployee(anID);
}
}
public static void UpdateEmployeeInfo(NorthwindEmployee ne) {
bool retval = ne.Save();
if (! retval) { throw new NorthwindDataException("UpdateEmployee failed."); }
}
public static void DeleteEmployee(NorthwindEmployee ne) {
bool retval = ne.Delete();
if (! retval) { throw new NorthwindDataException("DeleteEmployee failed."); }
}
// And so on...
}
public class NorthwindEmployee {
public NorthwindEmployee () {
ID = DBNull.Value;
lastName = "";
firstName = "";
title="";
titleOfCourtesy = "";
reportsTo = -1;
}
public NorthwindEmployee (object anID) {
this.ID = anID;
SqlConnection conn
SqlCommand sc =
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());
SqlDataReader sdr = null;
try {
conn.Open();
sdr = sc.ExecuteReader();
// Only loop once.
if (sdr != null && sdr.Read()) {
// The IEnumerable contains DataRowView objects.
this.firstName = sdr["FirstName"].ToString();
this.lastName = sdr["LastName"].ToString();
this.title = sdr["Title"].ToString();
this.titleOfCourtesy = sdr["TitleOfCourtesy"].ToString();
if (! sdr.IsDBNull(4)) {
this.reportsTo = sdr.GetInt32(4);
}
}
else {
throw new NorthwindDataException("Data not loaded for employee id.");
}
}
finally {
try {
if (sdr != null) sdr.Close();
conn.Close();
}
catch (SqlException) {
// Log an event in the Application Event Log.
throw;
}
}
}
private object ID;
public string EmpID {
get { return ID.ToString(); }
}
private string lastName;
public string LastName {
get { return lastName; }
set { lastName = value; }
}
private string firstName;
public string FirstName {
get { return firstName; }
set { firstName = value; }
}
public string FullName {
get { return FirstName + " " + LastName; }
}
private string title;
public String Title {
get { return title; }
set { title = value; }
}
private string titleOfCourtesy;
public string Courtesy {
get { return titleOfCourtesy; }
set { titleOfCourtesy = value; }
}
private int reportsTo;
public int Supervisor {
get { return reportsTo; }
set { reportsTo = value; }
}
public bool Save () {
// Implement persistence logic.
return true;
}
public bool Delete () {
// Implement delete logic.
return true;
}
}
internal class NorthwindDataException: Exception {
public NorthwindDataException(string msg) : base (msg) { }
}
}