ObjectDataSource.Update 方法

  • 參考

定義

命名空間:
System.Web.UI.WebControls
組件:
System.Web.dll

藉由呼叫由 UpdateMethod 屬性所識別的方法，同時使用 UpdateParameters 集合中的任何參數，執行更新作業。

public:
 int Update();
public int Update ();
member this.Update : unit -> int
Public Function Update () As Integer

傳回

Int32

表示基礎資料儲存中更新之資料列數目的值。

範例

本節包含兩個程式碼範例。 第一個程式碼範例示範如何使用控制項、 TextBox 控制項和數 ObjectDataSource 個 DropDownList 物件來更新資料。 第二個程式碼範例顯示 EmployeeLogic 第一個程式碼範例中使用的 類別。

下列程式碼範例示範如何使用控制項、 TextBox 控制項和數 ObjectDataSource 個 DropDownList 控制項來更新資料。 會顯示 DropDownList Northwind 員工的名稱，而 TextBox 控制項則用來輸入和更新位址資訊。 UpdateParameters由於集合包含系 ControlParameter 結至 所選取值的 DropDownList 物件，因此只有在選取員工之後，才會啟用引發 Update 作業的按鈕。

重要

這個範例有一個可接受使用者輸入的文字方塊，這可能會造成安全性威脅。 根據預設，ASP.NET Web 網頁會驗證使用者輸入未包含指令碼或 HTML 項目。 如需詳細資訊，請參閱 Script Exploits Overview (指令碼攻擊概觀)。

<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.CS" Assembly="Samples.AspNet.CS" %>
<%@ Page language="c#" %>
<%@ Import namespace="Samples.AspNet.CS" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<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();
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
  <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. -->

        <!-- Security Note: The ObjectDataSource uses a FormParameter,
             Security Note: which does not perform validation of input from the client.
             Security Note: To validate the value of the FormParameter,
             Security Note: handle the Updating event. -->

        <asp:objectdatasource
          id="ObjectDataSource2"
          runat="server"
          updatemethod="UpdateEmployeeWrapper"
          typename="Samples.AspNet.CS.EmployeeLogic">
          <updateparameters>
            <asp:controlparameter name="anID" controlid="DropDownList1" propertyname="SelectedValue" />
            <asp:formparameter name="anAddress" formfield="AddressBox" />
            <asp:formparameter name="aCity" formfield="CityBox" />
            <asp:formparameter name="aPostalCode" formfield="PostalCodeBox" />
          </updateparameters>
        </asp:objectdatasource>

        <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>

<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.VB" Assembly="Samples.AspNet.VB" %>
<%@ Page language="vb" %>
<%@ Import namespace="Samples.AspNet.VB" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">

' Add parameters and initialize the user interface
' only if an employee is selected.
Private Sub Page_Load(sender As Object, e As EventArgs)

  ' Be sure the text boxes are initialized with
  ' data from the currently selected employee.
  Dim selectedEmployee As NorthwindEmployee
  selectedEmployee = EmployeeLogic.GetEmployee(DropDownList1.SelectedValue)

  If Not selectedEmployee Is Nothing Then
    AddressBox.Text    = selectedEmployee.Address
    CityBox.Text       = selectedEmployee.City
    PostalCodeBox.Text = selectedEmployee.PostalCode

    Button1.Enabled = True
  Else
    Button1.Enabled = False
  End If
End Sub ' Page_Load

' Press the button to update.
Private Sub Btn_UpdateEmployee (sender As Object, e As CommandEventArgs )
  ObjectDataSource2.Update()
End Sub ' Btn_UpdateEmployee

</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
  <head>
    <title>ObjectDataSource - VB 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.VB.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. -->

        <!-- Security Note: The ObjectDataSource uses a FormParameter,
             Security Note: which does not perform validation of input from the client.
             Security Note: To validate the value of the FormParameter,
             Security Note: handle the Updating event. -->

        <asp:objectdatasource
          id="ObjectDataSource2"
          runat="server"
          updatemethod="UpdateEmployeeWrapper"
          typename="Samples.AspNet.VB.EmployeeLogic">
          <updateparameters>
            <asp:controlparameter name="anID" controlid="DropDownList1" propertyname="SelectedValue" />
            <asp:formparameter name="anAddress" formfield="AddressBox" />
            <asp:formparameter name="aCity" formfield="CityBox" />
            <asp:formparameter name="aPostalCode" formfield="PostalCodeBox" />
          </updateparameters>
        </asp:objectdatasource>

        <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>

下列程式碼範例顯示 EmployeeLogic 上述程式碼範例中使用的 類別。

namespace Samples.AspNet.CS {

using System;
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 one can perform on a NorthwindEmployee object.
  //
  public class EmployeeLogic {

    // Returns a collection of NorthwindEmployee objects.
    public static ICollection GetAllEmployees () {
      ArrayList al = new ArrayList();

      // Use the SqlDataSource class to wrap the
      // ADO.NET code required to query the database.
      ConnectionStringSettings cts = ConfigurationManager.ConnectionStrings["NorthwindConnection"];

      SqlDataSource sds
        = new SqlDataSource(cts.ConnectionString,
                            "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) {
      ArrayList al = GetAllEmployees() as ArrayList;
      IEnumerator enumerator = al.GetEnumerator();
      while (enumerator.MoveNext()) {
        // The IEnumerable contains initialized NorthwindEmployee objects.
        NorthwindEmployee ne = enumerator.Current as NorthwindEmployee;
        if (ne.EmpID.Equals(anID.ToString())) {
          return ne;
        }
      }
      return null;
    }
    public static void UpdateEmployee(NorthwindEmployee ne) {
      bool retval = ne.Update();
      if (! retval) { throw new NorthwindDataException("Employee update failed."); }
    }

    // This method is added as a conveniece wrapper on the original
    // implementation.
    public static void UpdateEmployeeWrapper(string anID,
                                             string anAddress,
                                             string aCity,
                                             string aPostalCode) {
      NorthwindEmployee ne = new NorthwindEmployee(anID);
      ne.Address = anAddress;
      ne.City = aCity;
      ne.PostalCode = aPostalCode;
      UpdateEmployee(ne);
    }

    // And so on...
  }

  public class NorthwindEmployee {

    public NorthwindEmployee (object anID) {
      this.ID = anID;

      ConnectionStringSettings cts = ConfigurationManager.ConnectionStrings["NorthwindConnection"];
      SqlConnection conn = new SqlConnection (cts.ConnectionString);
      SqlCommand sc =
        new SqlCommand(" SELECT FirstName,LastName,Address,City,PostalCode " +
                       " 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();

        // This is not a while loop. It only loops once.
        if (sdr != null && sdr.Read()) {
          // The IEnumerable contains DataRowView objects.
          this.firstName       = sdr["FirstName"].ToString();
          this.lastName        = sdr["LastName"].ToString();
          this.address         = sdr["Address"].ToString();
          this.city            = sdr["City"].ToString();
          this.postalCode      = sdr["PostalCode"].ToString();
        }
        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 object EmpID {
      get { return ID; }
    }

    private string lastName;
    public string LastName {
      set { lastName = value; }
    }

    private string firstName;
    public string FirstName {
      set { firstName = value;  }
    }

    public string FullName {
      get { return firstName + " " + lastName; }
    }

    private string address;
    public string Address {
      get { return address; }
      set { address = value;  }
    }

    private string city;
    public string City {
      get { return city; }
      set { city = value;  }
    }

    private string postalCode;
    public string PostalCode {
      get { return postalCode; }
      set { postalCode = value;  }
    }

    public bool Update () {

      // Implement Update logic.

      return true;
    }
  }

  internal class NorthwindDataException: Exception {
    public NorthwindDataException(string msg) : base (msg) { }
  }
}

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 one 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()

      ' Use the SqlDataSource class to wrap the
      ' ADO.NET code required to query the database.
      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
      Dim al As ArrayList = CType(GetAllEmployees(), ArrayList)
      Dim enumerator As IEnumerator = al.GetEnumerator()
      While enumerator.MoveNext()
         ' The IEnumerable contains initialized NorthwindEmployee objects.
         Dim ne As NorthwindEmployee = CType(enumerator.Current,NorthwindEmployee)
         If ne.EmpID.Equals(anID.ToString()) Then
            Return ne
         End If
      End While
      Return Nothing
   End Function 'GetEmployee

   Public Shared Sub UpdateEmployee(ne As NorthwindEmployee)
      Dim retval As Boolean = ne.Update()
      If Not retval Then
         Throw New NorthwindDataException("Employee update failed.")
      End If
   End Sub

   ' This method is added as a conveniece wrapper on the original
   ' implementation.
   Public Shared Sub UpdateEmployeeWrapper(anID As String, _
                                           anAddress As String, _
                                           aCity As String, _
                                           aPostalCode As String)
      Dim ne As New NorthwindEmployee(anID)
      ne.Address = anAddress
      ne.City = aCity
      ne.PostalCode = aPostalCode
      UpdateEmployee(ne)
   End Sub
   ' And so on...

End Class

Public Class NorthwindEmployee

   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,Address,City,PostalCode " & _
                               " 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()

         ' This is not a while loop. It only loops 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.aAddress = sdr("Address").ToString()
            Me.aCity = sdr("City").ToString()
            Me.aPostalCode = sdr("PostalCode").ToString()
         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

   Private ID As Object
   Public ReadOnly Property EmpID() As Object
      Get
         Return ID
      End Get
   End Property

   Private aLastName As String
   Public WriteOnly Property LastName() As String
      Set
         aLastName = value
      End Set
   End Property

   Private aFirstName As String
   Public WriteOnly Property FirstName() As String
      Set
         aFirstName = value
      End Set
   End Property

   Public ReadOnly Property FullName() As String
      Get
         Return aFirstName & " " & aLastName
      End Get
   End Property

   Private aAddress As String
   Public Property Address() As String
      Get
         Return aAddress
      End Get
      Set
         aAddress = value
      End Set
   End Property

   Private aCity As String
   Public Property City() As String
      Get
         Return aCity
      End Get
      Set
         aCity = value
      End Set
   End Property

   Private aPostalCode As String
   Public Property PostalCode() As String
      Get
         Return aPostalCode
      End Get
      Set
         aPostalCode = value
      End Set
   End Property

   Public Function Update() As Boolean

      ' Implement Update logic.
      Return True

   End Function 'Update

End Class

Friend Class NorthwindDataException
   Inherits Exception

   Public Sub New(msg As String)
      MyBase.New(msg)
   End Sub

End Class
End Namespace

備註

假設商務物件會一次更新一筆記錄，而不是批次中的資料。

Update在執行作業之前，會 OnUpdating 呼叫 方法來引發 Updating 事件。 您可以處理 Updating 事件來檢查參數的值，並在作業之前 Update 執行任何前置處理。 若要執行更新作業，物件會 ObjectDataSourceView 使用反映來建立 屬性所 TypeName 識別之物件的實例。 然後，它會使用任何相關聯的 UpdateParameters 屬性呼叫 屬性所 UpdateMethod 識別的方法。 Update作業完成之後， OnUpdated 會呼叫 方法來引發 Updated 事件。 您可以處理 Updated 事件來檢查任何傳回值、輸出參數和例外狀況，以及執行任何後續處理。

方法 Update 會委派給 Update 與 ObjectDataSource 控制項相關聯之 的 ObjectDataSourceView 方法。

如需參數合併、物件存留期和方法解析的詳細資訊，請參閱 UpdateMethod 。

重要

您應該驗證您從用戶端收到的任何參數值。 執行時間只會將參數值取代為 UpdateMethod 屬性。

資料繫結控制項

ObjectDataSource當控制項與資料繫結控制項相關聯時，例如 GridView 控制項，就不需要從頁面代碼呼叫 Update 方法。 方法 Update 會改為由資料繫結控制項直接叫用。

適用於

另請參閱