Share via

OleDbDataAdapter.RowUpdating 事件

  • 项目

在对数据源执行命令前的 Update 过程中发生。试图进行更新。因此，事件发生。

**命名空间:**System.Data.OleDb
**程序集:**System.Data（在 system.data.dll 中）

语法

声明
Public Event RowUpdating As OleDbRowUpdatingEventHandler
用法
Dim instance As OleDbDataAdapter
Dim handler As OleDbRowUpdatingEventHandler

AddHandler instance.RowUpdating, handler

public event OleDbRowUpdatingEventHandler RowUpdating

public:
event OleDbRowUpdatingEventHandler^ RowUpdating {
    void add (OleDbRowUpdatingEventHandler^ value);
    void remove (OleDbRowUpdatingEventHandler^ value);
}

/** @event */
public void add_RowUpdating (OleDbRowUpdatingEventHandler value)

/** @event */
public void remove_RowUpdating (OleDbRowUpdatingEventHandler value)

JScript 支持使用事件，但不支持进行新的声明。

备注

当使用 Update 时，每一个更新的数据行都会发生两个事件。执行顺序如下：

  1. 将 DataRow 中的值移至参数值。

  2. 引发 OnRowUpdating 事件。

  3. 执行命令。

  4. 如果该命令设置为 FirstReturnedRecord，返回的第一项结果将放置在 DataRow 中。

  5. 如果存在输出参数，它们将被放在 DataRow 中。

  6. 引发 OnRowUpdated 事件。

  7. 调用 AcceptChanges。

示例

下面的示例演示正在使用的 RowUpdating 和 RowUpdated 事件。

Public Sub CreateDataAdapter(ByVal connectionString As String)
    Using connection As New OleDbConnection(connectionString)
        Dim adapter As OleDbDataAdapter = New OleDbDataAdapter( _
            "SELECT * FROM Customers WHERE CustomerID = 'ALFKI'", connection)

        adapter.InsertCommand = New OleDbCommand( _
            "INSERT INTO Customers (CustomerID, CompanyName) VALUES(?, ?)", _
            connection)

        adapter.InsertCommand.Parameters.Add( _
            "@CustomerID", OleDbType.VarChar, 5, "CustomerID")
        adapter.InsertCommand.Parameters.Add( _
            "@CompanyName", OleDbType.VarChar, 30, "CompanyName")

        connection.Open()

        Dim custDS As DataSet = New DataSet()
        adapter.Fill(custDS, "Customers")

        Dim custRow As DataRow = custDS.Tables("Customers").NewRow()
        custRow("CustomerID") = "NEWCO"
        custRow("CompanyName") = "New Company"
        custDS.Tables("Customers").Rows.Add(custRow)

        ' add handlers
        AddHandler adapter.RowUpdating, _
            New OleDbRowUpdatingEventHandler(AddressOf OnRowUpdating)
        AddHandler adapter.RowUpdated, _
            New OleDbRowUpdatedEventHandler(AddressOf OnRowUpdated)

        adapter.Update(custDS, "Customers")

        ' remove handlers
        RemoveHandler adapter.RowUpdating, _
            New OleDbRowUpdatingEventHandler(AddressOf OnRowUpdating)
        RemoveHandler adapter.RowUpdated, _
            New OleDbRowUpdatedEventHandler(AddressOf OnRowUpdated)

        Dim row As DataRow
        For Each row In custDS.Tables("Customers").Rows
            If row.HasErrors Then Console.WriteLine(row.RowError)
        Next
    End Using
End Sub

Sub OnRowUpdating(ByVal sender As Object, _
    ByVal args As OleDbRowUpdatingEventArgs)

    If args.StatementType = StatementType.Insert Then
        Dim writer As System.IO.TextWriter = _
            System.IO.File.AppendText("Inserts.log")
        writer.WriteLine("{0}: Customer {1} Inserted.", _
            DateTime.Now, args.Row("CustomerID"))
        writer.Close()
    End If
End Sub

Sub OnRowUpdated(ByVal sender As Object, _
    ByVal args As OleDbRowUpdatedEventArgs)

    If args.Status = UpdateStatus.ErrorsOccurred Then
        args.Row.RowError = args.Errors.Message
        args.Status = UpdateStatus.SkipCurrentRow
    End If
End Sub

public static void CreateDataAdapter(
    string connectionString)
{
    using (OleDbConnection connection = new OleDbConnection(connectionString))
    {
        OleDbDataAdapter adapter = new OleDbDataAdapter(
            "SELECT * FROM Customers WHERE CustomerID = 'ALFKI'", connection);

        adapter.InsertCommand = new OleDbCommand(
            "INSERT INTO Customers (CustomerID, CompanyName) VALUES(?, ?)", 
            connection);

        adapter.InsertCommand.Parameters.Add(
            "@CustomerID", OleDbType.VarChar, 5, "CustomerID");
        adapter.InsertCommand.Parameters.Add(
            "@CompanyName", OleDbType.VarChar, 30, "CompanyName");

        connection.Open();

        DataSet custDS = new DataSet();
        adapter.Fill(custDS, "Customers");

        DataRow custRow = custDS.Tables["Customers"].NewRow();
        custRow["CustomerID"] = "NEWCO";
        custRow["CompanyName"] = "New Company";
        custDS.Tables["Customers"].Rows.Add(custRow);

        // add handlers
        adapter.RowUpdating += new OleDbRowUpdatingEventHandler(OnRowUpdating);
        adapter.RowUpdated += new OleDbRowUpdatedEventHandler(OnRowUpdated);

        adapter.Update(custDS, "Customers");

        // remove handlers
        adapter.RowUpdating -= new OleDbRowUpdatingEventHandler(OnRowUpdating);
        adapter.RowUpdated -= new OleDbRowUpdatedEventHandler(OnRowUpdated);

        foreach (DataRow row in custDS.Tables["Customers"].Rows)
        {
            if (row.HasErrors)
                Console.WriteLine(row.RowError);
        }
    }
}

protected static void OnRowUpdating(object sender, 
    OleDbRowUpdatingEventArgs args)
{
    if (args.StatementType == StatementType.Insert)
    {
        System.IO.TextWriter writer = System.IO.File.AppendText("Inserts.log");
        writer.WriteLine("{0}: Customer {1} Inserted.", 
            DateTime.Now, args.Row["CustomerID"]);
        writer.Close();
    }
}

protected static void OnRowUpdated(object sender, OleDbRowUpdatedEventArgs args)
{
    if (args.Status == UpdateStatus.ErrorsOccurred)
    {
        args.Row.RowError = args.Errors.Message;
        args.Status = UpdateStatus.SkipCurrentRow;
    }
}

using System;
using System.Data;
using System.Data.OleDb;

class Class1
{
    static void Main()
    {
        string x = "Provider=SQLOLEDB;Data Source=(local);Integrated Security=SSPI;Initial Catalog=Northwind";
        CreateDataAdapter(x);
    }

    public static void CreateDataAdapter(
        string connectionString)
    {
        using (OleDbConnection connection = new OleDbConnection(connectionString))
        {
            OleDbDataAdapter adapter = new OleDbDataAdapter(
                "SELECT * FROM Customers WHERE CustomerID = 'ALFKI'", connection);

            adapter.InsertCommand = new OleDbCommand(
                "INSERT INTO Customers (CustomerID, CompanyName) VALUES(?, ?)", 
                connection);

            adapter.InsertCommand.Parameters.Add(
                "@CustomerID", OleDbType.VarChar, 5, "CustomerID");
            adapter.InsertCommand.Parameters.Add(
                "@CompanyName", OleDbType.VarChar, 30, "CompanyName");

            connection.Open();

            DataSet custDS = new DataSet();
            adapter.Fill(custDS, "Customers");

            DataRow custRow = custDS.Tables["Customers"].NewRow();
            custRow["CustomerID"] = "NEWCO";
            custRow["CompanyName"] = "New Company";
            custDS.Tables["Customers"].Rows.Add(custRow);

            // add handlers
            adapter.RowUpdating += new OleDbRowUpdatingEventHandler(OnRowUpdating);
            adapter.RowUpdated += new OleDbRowUpdatedEventHandler(OnRowUpdated);

            adapter.Update(custDS, "Customers");

            // remove handlers
            adapter.RowUpdating -= new OleDbRowUpdatingEventHandler(OnRowUpdating);
            adapter.RowUpdated -= new OleDbRowUpdatedEventHandler(OnRowUpdated);

            foreach (DataRow row in custDS.Tables["Customers"].Rows)
            {
                if (row.HasErrors)
                    Console.WriteLine(row.RowError);
            }
        }
    }

    protected static void OnRowUpdating(object sender, 
        OleDbRowUpdatingEventArgs args)
    {
        if (args.StatementType == StatementType.Insert)
        {
            System.IO.TextWriter writer = System.IO.File.AppendText("Inserts.log");
            writer.WriteLine("{0}: Customer {1} Inserted.", 
                DateTime.Now, args.Row["CustomerID"]);
            writer.Close();
        }
    }

    protected static void OnRowUpdated(object sender, OleDbRowUpdatedEventArgs args)
    {
        if (args.Status == UpdateStatus.ErrorsOccurred)
        {
            args.Row.RowError = args.Errors.Message;
            args.Status = UpdateStatus.SkipCurrentRow;
        }
    }

平台

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

.NET Framework 并不是对每个平台的所有版本都提供支持。有关受支持版本的列表，请参见系统要求。

版本信息

.NET Framework

受以下版本支持：2.0、1.1、1.0

请参见

参考

OleDbDataAdapter 类
OleDbDataAdapter 成员
System.Data.OleDb 命名空间

其他资源

使用 DataAdapter