SqlDataSource.Updating 事件 (System.Web.UI.WebControls)

.NET Framework 類別庫

SqlDataSource..::.Updating 事件

更新：2007 年 11 月

在更新作業之前發生。

命名空間： System.Web.UI.WebControls
組件： System.Web (在 System.Web.dll 中)

語法

Visual Basic (宣告)

Public Event Updating As SqlDataSourceCommandEventHandler

Visual Basic (使用方式)

Dim instance As SqlDataSource
Dim handler As SqlDataSourceCommandEventHandler

AddHandler instance.Updating, handler

public event SqlDataSourceCommandEventHandler Updating

Visual C++

public:
 event SqlDataSourceCommandEventHandler^ Updating {
    void add (SqlDataSourceCommandEventHandler^ value);
    void remove (SqlDataSourceCommandEventHandler^ value);
}

/** @event */
public void add_Updating (SqlDataSourceCommandEventHandler value)
/** @event */
public void remove_Updating (SqlDataSourceCommandEventHandler value)

JScript

JScript 不支援事件。

ASP.NET

<asp:SqlDataSource OnUpdating="SqlDataSourceCommandEventHandler" />

備註

處理 Updating 事件，執行您應用程式特定的其他初始設定作業，以驗證參數的值或在 SqlDataSource 控制項執行更新作業之前，變更參數值。呼叫事件處理常式委派時，尚未開啟基礎資料來源的連接。因此，您無法直接取消 Update 資料庫作業，即使是在 SqlDataSourceCommandEventArgs 物件公開的 DbCommand 物件上呼叫 Cancel 方法。不過，您可以將 SqlDataSourceCommandEventArgs 的 Cancel 屬性設定為 true，以取消資料庫作業。

如需處理事件的詳細資訊，請參閱使用事件。

安全性注意事項：
插入參數中的值不會經過驗證，這可能會造成安全性威脅。在執行查詢之前，請使用 Updating 事件驗證參數值。如需詳細資訊，請參閱指令碼攻擊概觀。

範例

在下列程式碼中，示範了如何在 DropDownList 控制項中，顯示從 Microsoft SQL Server 資料庫擷取的資料，並使用 TextBox 控制項更新資料錄。此範例顯示在使用 SqlDataSource 控制項更新資料時，如何使用 DbTransaction 物件，加入交易內容。

Visual Basic

<%@Page  Language="VB" %>
<%@Import Namespace="System.Data" %>
<%@Import Namespace="System.Data.Common" %>
<%@Import Namespace="System.Diagnostics" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

 Sub On_Click(ByVal source As Object, ByVal e As EventArgs)
        SqlDataSource1.Update()
 End Sub 'On_Click

 Sub On_Sql_Updating(ByVal source As Object, ByVal e As SqlDataSourceCommandEventArgs)
     Dim command as DbCommand
     Dim connection as DbConnection
     Dim transaction as DbTransaction

     command    = e.Command
     connection = command.Connection     
     connection.Open()     
     transaction = connection.BeginTransaction()
     command.Transaction = transaction

 End Sub 'On_Sql_Updating

 Sub On_Sql_Updated(ByVal source As Object, ByVal e As SqlDataSourceStatusEventArgs)

    Dim command As DbCommand
    Dim transaction As DbTransaction

    command = e.Command
    transaction = command.Transaction

    ' In this code example the OtherProcessSucceeded variable represents
    ' the outcome of some other process that occurs whenever the data is 
    ' updated, and must succeed for the data change to be committed. For 
    ' simplicity, we set this value to true. 
    Dim OtherProcessSucceeded as Boolean = True

    If (OtherProcessSucceeded) Then
        transaction.Commit()
        Label2.Text="The record was updated successfully!"
    Else    
        transaction.Rollback()
        Label2.Text="The record was not updated."
    End If
 End Sub ' On_Sql_Updated
</script>

<html  >
  <head runat="server">
    <title>ASP.NET Example</title>
</head>
<body>
    <form id="form1" runat="server">
      <asp:SqlDataSource
          id="SqlDataSource1"
          runat="server"
          ConnectionString="<%$ ConnectionStrings:MyNorthwind%>"
          SelectCommand="SELECT EmployeeID, LastName, Address FROM Employees"
          UpdateCommand="UPDATE Employees SET Address=@Address WHERE EmployeeID=@EmployeeID"
          OnUpdating="On_Sql_Updating"
          OnUpdated ="On_Sql_Updated">
          <UpdateParameters>
              <asp:ControlParameter Name="Address" ControlId="TextBox1" PropertyName="Text"/>
              <asp:ControlParameter Name="EmployeeID" ControlId="DropDownList1" PropertyName="SelectedValue"/>
          </UpdateParameters>
      </asp:SqlDataSource>

      <asp:DropDownList
          id="DropDownList1"
          runat="server"
          DataTextField="LastName"
          DataValueField="EmployeeID"
          DataSourceID="SqlDataSource1">
      </asp:DropDownList>

      <br />
      <asp:Label id="Label1" runat="server" Text="Enter a new address for the selected user."
        AssociatedControlID="TextBox1" />
      <asp:TextBox id="TextBox1" runat="server" />
      <asp:Button id="Submit" runat="server" Text="Submit" OnClick="On_Click" />

      <br /><asp:Label id="Label2" runat="server" Text="" />

    </form>
  </body>
</html>

<%@Page  Language="C#" %>
<%@Import Namespace="System.Data" %>
<%@Import Namespace="System.Data.Common" %>
<%@Import Namespace="System.Data.SqlClient" %>
<%@Import Namespace="System.Diagnostics" %>
<!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 On_Click(Object source, EventArgs e) {    
    SqlDataSource1.Update();
 }

 private void OnSqlUpdating(Object source, SqlDataSourceCommandEventArgs e) {
    DbCommand command = e.Command;
    DbConnection cx  = command.Connection;    
    cx.Open();    
    DbTransaction tx = cx.BeginTransaction();
    command.Transaction = tx;
 }

 private void OnSqlUpdated(Object source, SqlDataSourceStatusEventArgs e) {
    DbCommand command = e.Command;
    DbTransaction tx = command.Transaction;

    // In this code example the OtherProcessSucceeded variable represents
    // the outcome of some other process that occurs whenever the data is 
    // updated, and must succeed for the data change to be committed. For 
    // simplicity, we set this value to true. 
    bool OtherProcessSucceeded = true;

    if (OtherProcessSucceeded) {
        tx.Commit();
        Label2.Text="The record was updated successfully!";
    }
    else {
        tx.Rollback();
        Label2.Text="The record was not updated.";
    }
 }

</script>

<html  >
  <head runat="server">
    <title>ASP.NET Example</title>
</head>
<body>
    <form id="form1" runat="server">
      <asp:SqlDataSource
          id="SqlDataSource1"
          runat="server"
          ConnectionString="<%$ ConnectionStrings:MyNorthwind%>"
          SelectCommand="SELECT EmployeeID, LastName, Address FROM Employees"
          UpdateCommand="UPDATE Employees SET Address=@Address WHERE EmployeeID=@EmployeeID"
          OnUpdating="OnSqlUpdating"
          OnUpdated ="OnSqlUpdated">
          <UpdateParameters>
              <asp:ControlParameter Name="Address" ControlId="TextBox1" PropertyName="Text"/>
              <asp:ControlParameter Name="EmployeeID" ControlId="DropDownList1" PropertyName="SelectedValue"/>
          </UpdateParameters>
      </asp:SqlDataSource>

      <asp:DropDownList
          id="DropDownList1"
          runat="server"
          DataTextField="LastName"
          DataValueField="EmployeeID"
          DataSourceID="SqlDataSource1">
      </asp:DropDownList>

      <br />
      <asp:Label id="Label1" runat="server" Text="Enter a new address for the selected user."
        AssociatedControlID="TextBox1" />
      <asp:TextBox id="TextBox1" runat="server" />
      <asp:Button id="Submit" runat="server" Text="Submit" OnClick="On_Click" />

      <br /><asp:Label id="Label2" runat="server" Text="" />

    </form>
  </body>
</html>

<%@Page  Language="VJ#" %>
<%@Import Namespace="System.Data" %>
<%@Import Namespace="System.Data.Common" %>
<%@Import Namespace="System.Diagnostics" %>
<!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 On_Click(Object source, System.EventArgs e)
    {
        try {
            SqlDataSource1.Update();
        }
        catch (System.Exception except) {
            // Handle Exception
        }

        Label2.set_Text("The record was updated successfully!");
    } //On_Click

    private void OnSqlUpdate(Object source, SqlDataSourceCommandEventArgs e)
    {
        // Log the command in the Event Log on the Web server.
        String logInfo = e.get_Command().get_CommandText() 
            + " is being submitted to the database.";

        IEnumerator ie = e.get_Command().get_Parameters().GetEnumerator();
        while (ie.MoveNext()) {
            DbParameter param = ((DbParameter)(ie.get_Current()));
            logInfo = logInfo + " " + param.get_ParameterName()+ "=" 
            + param.get_Value();
        }

        EventLog log = new EventLog();
        log.set_Log("Application");
        log.set_Source("ASP.NET Example");
        log.WriteEntry(logInfo);
    } //OnSqlUpdate    

</script>

<html  >
  <head runat="server">
    <title>ASP.NET Example</title>
</head>
<body>
    <form id="form1" runat="server">
      <asp:SqlDataSource
          id="SqlDataSource1"
          runat="server"
          ConnectionString="Data Source=localhost;Integrated Security=SSPI;Initial Catalog=Northwind;"
          SelectCommand="SELECT EmployeeID, LastName, Address FROM Employees"
          UpdateCommand="UPDATE Employees SET Address=@Address WHERE EmployeeID=@EmployeeID"
          OnUpdating="OnSqlUpdate">
          <UpdateParameters>
              <asp:ControlParameter Name="Address" ControlId="TextBox1" PropertyName="Text"/>
              <asp:ControlParameter Name="EmployeeID" ControlId="DropDownList1" PropertyName="SelectedValue"/>
          </UpdateParameters>
      </asp:SqlDataSource>

      <asp:DropDownList
          id="DropDownList1"
          runat="server"
          DataTextField="LastName"
          DataValueField="EmployeeID"
          DataSourceID="SqlDataSource1">
      </asp:DropDownList>

      <br />
      <asp:Label id="Label1" runat="server" Text="Enter a new address for the selected user."
        AssociatedControlID="TextBox1" />
      <asp:TextBox id="TextBox1" runat="server" />
      <asp:Button id="Submit" runat="server" Text="Submit" OnClick="On_Click" />

      <br /><asp:Label id="Label2" runat="server" Text="" />

    </form>
  </body>
</html>

平台

Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

.NET Framework 和 .NET Compact Framework 並不支援各種平台的所有版本。如需支援平台版本的相關資訊，請參閱 .NET Framework 系統需求。

版本資訊