共用方式為


SqlCommand.BeginExecuteNonQuery 方法

定義

起始這個 SqlCommand 所描述之 Transact-SQL 陳述式或預存程序的非同步執行。

多載

BeginExecuteNonQuery()

起始這個 SqlCommand 所描述之 Transact-SQL 陳述式或預存程序的非同步執行。

BeginExecuteNonQuery(AsyncCallback, Object)

如果已有回呼程序和狀態資訊,會啟始 Transact-SQL 陳述式或此 SqlCommand 所描述預存程序的非同步執行。

BeginExecuteNonQuery()

起始這個 SqlCommand 所描述之 Transact-SQL 陳述式或預存程序的非同步執行。

public:
 IAsyncResult ^ BeginExecuteNonQuery();
public IAsyncResult BeginExecuteNonQuery ();
member this.BeginExecuteNonQuery : unit -> IAsyncResult
Public Function BeginExecuteNonQuery () As IAsyncResult

傳回

IAsyncResult 可用於輪詢或等待結果 (或兩者)。叫用傳回受影響資料列數目的 EndExecuteNonQuery(IAsyncResult) 時,也需要這個值。

例外狀況

Value 設為 Stream 時,使用 BinaryVarBinary 以外的 SqlDbType。 如需串流的詳細資訊,請參閱 SqlClient 串流支援

-或-

SqlDbType當 設定TextReader為 時Value,會使用 CharNCharNVarCharVarCharXml 以外的 。

-或-

Value 設定為 XmlReader 時,使用 Xml 以外的 SqlDbType

執行命令文字時發生的任何錯誤。

-或-

串流作業期間發生逾時。 如需串流的詳細資訊,請參閱 SqlClient 串流支援

定義這個 SqlCommand 之連接的連接字串中未包含名稱/值組 "Asynchronous Processing=true"。

-或-

在串流作業期間已關閉或卸除的 SqlConnection。 如需串流的詳細資訊,請參閱 SqlClient 串流支援

StreamXmlReaderTextReader 物件在串流作業期間發生錯誤。 如需串流的詳細資訊,請參閱 SqlClient 串流支援

StreamXmlReaderTextReader 物件在串流作業期間已關閉。 如需串流的詳細資訊,請參閱 SqlClient 串流支援

範例

下列主控台應用程式會在 AdventureWorks 範例資料庫中建立更新數據,以異步方式執行其工作。 為了模擬長時間執行的程序,此範例會在命令文字中插入 WAITFOR 陳述式。 一般而言,您不需要投入心力讓命令執行速度變慢,但在此案例中這麼做可讓您更輕鬆地示範異步行為。

using System.Data.SqlClient;

class Class1
{
    static void Main()
    {
        // This is a simple example that demonstrates the usage of the
        // BeginExecuteNonQuery functionality.
        // The WAITFOR statement simply adds enough time to prove the
        // asynchronous nature of the command.

        string commandText =
            "UPDATE Production.Product SET ReorderPoint = ReorderPoint + 1 " +
            "WHERE ReorderPoint Is Not Null;" +
            "WAITFOR DELAY '0:0:3';" +
            "UPDATE Production.Product SET ReorderPoint = ReorderPoint - 1 " +
            "WHERE ReorderPoint Is Not Null";

        RunCommandAsynchronously(commandText, GetConnectionString());

        Console.WriteLine("Press ENTER to continue.");
        Console.ReadLine();
    }

    private static void RunCommandAsynchronously(
        string commandText, string connectionString)
    {
        // Given command text and connection string, asynchronously execute
        // the specified command against the connection. For this example,
        // the code displays an indicator as it is working, verifying the
        // asynchronous behavior.
        using (SqlConnection connection =
                   new SqlConnection(connectionString))
        {
            try
            {
                int count = 0;
                SqlCommand command = new SqlCommand(commandText, connection);
                connection.Open();

                IAsyncResult result = command.BeginExecuteNonQuery();
                while (!result.IsCompleted)
                {
                    Console.WriteLine("Waiting ({0})", count++);
                    // Wait for 1/10 second, so the counter
                    // does not consume all available resources
                    // on the main thread.
                    System.Threading.Thread.Sleep(100);
                }
                Console.WriteLine("Command complete. Affected {0} rows.",
                    command.EndExecuteNonQuery(result));
            }
            catch (SqlException ex)
            {
                Console.WriteLine("Error ({0}): {1}", ex.Number, ex.Message);
            }
            catch (InvalidOperationException ex)
            {
                Console.WriteLine("Error: {0}", ex.Message);
            }
            catch (Exception ex)
            {
                // You might want to pass these errors
                // back out to the caller.
                Console.WriteLine("Error: {0}", ex.Message);
            }
        }
    }

    private static string GetConnectionString()
    {
        // To avoid storing the connection string in your code,
        // you can retrieve it from a configuration file.

        // If you have not included "Asynchronous Processing=true" in the
        // connection string, the command is not able
        // to execute asynchronously.
        return "Data Source=(local);Integrated Security=SSPI;" +
            "Initial Catalog=AdventureWorks; Asynchronous Processing=true";
    }
}
Imports System.Data.SqlClient

Module Module1

    Sub Main()
        ' This is a simple example that demonstrates the usage of the 
        ' BeginExecuteNonQuery functionality.
        ' The WAITFOR statement simply adds enough time to prove the 
        ' asynchronous nature of the command.
        Dim commandText As String = _
         "UPDATE Production.Product SET ReorderPoint = ReorderPoint + 1 " & _
         "WHERE ReorderPoint Is Not Null;" & _
         "WAITFOR DELAY '0:0:3';" & _
         "UPDATE Production.Product SET ReorderPoint = ReorderPoint - 1 " & _
         "WHERE ReorderPoint Is Not Null"

        RunCommandAsynchronously(commandText, GetConnectionString())

        Console.WriteLine("Press ENTER to continue.")
        Console.ReadLine()
    End Sub

    Private Sub RunCommandAsynchronously( _
     ByVal commandText As String, ByVal connectionString As String)

        ' Given command text and connection string, asynchronously execute
        ' the specified command against the connection. For this example,
        ' the code displays an indicator as it is working, verifying the 
        ' asynchronous behavior. 
        Using connection As New SqlConnection(connectionString)
            Try
                Dim count As Integer = 0
                Dim command As New SqlCommand(commandText, connection)
                connection.Open()
                Dim result As IAsyncResult = command.BeginExecuteNonQuery()
                While Not result.IsCompleted
                    Console.WriteLine("Waiting ({0})", count)
                    ' Wait for 1/10 second, so the counter
                    ' does not consume all available resources 
                    ' on the main thread.
                    Threading.Thread.Sleep(100)
                    count += 1
                End While
                Console.WriteLine("Command complete. Affected {0} rows.", _
                    command.EndExecuteNonQuery(result))
            Catch ex As SqlException
                Console.WriteLine("Error ({0}): {1}", ex.Number, ex.Message)
            Catch ex As InvalidOperationException
                Console.WriteLine("Error: {0}", ex.Message)
            Catch ex As Exception
                ' You might want to pass these errors
                ' back out to the caller.
                Console.WriteLine("Error: {0}", ex.Message)
            End Try
        End Using
    End Sub

    Private Function GetConnectionString() As String
        ' To avoid storing the connection string in your code,            
        ' you can retrieve it from a configuration file. 

        ' If you have not included "Asynchronous Processing=true" in the
        ' connection string, the command is not able
        ' to execute asynchronously.
        Return "Data Source=(local);Integrated Security=SSPI;" & _
          "Initial Catalog=AdventureWorks; Asynchronous Processing=true"
    End Function
End Module

備註

方法 BeginExecuteNonQuery 會啟動異步執行 Transact-SQL 語句或未傳回數據列的預存程式的程式,讓其他工作可以在語句執行時同時執行。 當語句完成時,開發人員必須呼叫 EndExecuteNonQuery 方法來完成作業。 方法 BeginExecuteNonQuery 會立即傳回,但在程式代碼執行對應的 EndExecuteNonQuery 方法呼叫之前,它不得執行任何其他針對相同 SqlCommand 對象啟動同步或異步執行的呼叫。 EndExecuteNonQuery在命令的執行完成之前呼叫 ,會導致SqlCommand對象封鎖直到執行完成為止。

請注意,命令文字和參數會同步傳送至伺服器。 如果傳送大型命令或許多參數,這個方法可能會在寫入期間封鎖。 傳送命令之後,方法會立即傳回,而不需要等候來自伺服器的答案,也就是讀取是異步的。

由於此多載不支援回呼程式,因此開發人員必須輪詢以判斷命令是否已完成,方法是使用 IsCompleted 方法所BeginExecuteNonQuery傳回 的 IAsyncResult 屬性,或等候使用AsyncWaitHandle所傳回 IAsyncResult之 屬性完成一或多個命令。

這個方法會 CommandTimeout 忽略 屬性。

另請參閱

適用於

BeginExecuteNonQuery(AsyncCallback, Object)

如果已有回呼程序和狀態資訊,會啟始 Transact-SQL 陳述式或此 SqlCommand 所描述預存程序的非同步執行。

public:
 IAsyncResult ^ BeginExecuteNonQuery(AsyncCallback ^ callback, System::Object ^ stateObject);
public IAsyncResult BeginExecuteNonQuery (AsyncCallback callback, object stateObject);
member this.BeginExecuteNonQuery : AsyncCallback * obj -> IAsyncResult
Public Function BeginExecuteNonQuery (callback As AsyncCallback, stateObject As Object) As IAsyncResult

參數

callback
AsyncCallback

完成執行命令時叫用的 AsyncCallback 委派。 傳遞 null (在 Microsoft Visual Basic 中為 Nothing) 以表示不需要回呼。

stateObject
Object

已傳遞至回呼程序的使用者定義狀態物件。 使用 AsyncState 屬性,從回呼程序內擷取這個物件。

傳回

IAsyncResult 可用於輪詢或等待結果 (或兩者)。叫用傳回受影響資料列數目的 EndExecuteNonQuery(IAsyncResult) 時,也需要這個值。

例外狀況

Value 設為 Stream 時,使用 BinaryVarBinary 以外的 SqlDbType。 如需串流的詳細資訊,請參閱 SqlClient 串流支援

-或-

SqlDbType當 設定TextReader為 時Value,會使用 CharNCharNVarCharVarCharXml 以外的 。

-或-

Value 設定為 XmlReader 時,使用 Xml 以外的 SqlDbType

執行命令文字時發生的任何錯誤。

-或-

串流作業期間發生逾時。 如需串流的詳細資訊,請參閱 SqlClient 串流支援

定義這個 SqlCommand 之連接的連接字串中未包含名稱/值組 "Asynchronous Processing=true"。

-或-

在串流作業期間已關閉或卸除的 SqlConnection。 如需串流的詳細資訊,請參閱 SqlClient 串流支援

StreamXmlReaderTextReader 物件在串流作業期間發生錯誤。 如需串流的詳細資訊,請參閱 SqlClient 串流支援

StreamXmlReaderTextReader 物件在串流作業期間已關閉。 如需串流的詳細資訊,請參閱 SqlClient 串流支援

範例

下列 Windows 應用程式示範如何使用 BeginExecuteNonQuery 方法,執行包含數秒延遲的 Transact-SQL 語句, (模擬長時間執行的命令) 。

此範例示範許多重要的技術。 這包括呼叫從個別線程與窗體互動的方法。 此外,此範例示範如何封鎖使用者多次同時執行命令,以及如何確保表單在呼叫回呼程式之前不會關閉。

若要設定此範例,請建立新的 Windows 應用程式。 Button將控件和Label控件放在表單上, (接受每個控件的預設名稱) 。 將下列程式代碼新增至表單的 類別,視您的環境需要修改 連接字串。

using System.Data.SqlClient;

namespace Microsoft.AdoDotNet.CodeSamples
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        // Hook up the form's Load event handler (you can double-click on
        // the form's design surface in Visual Studio), and then add
        // this code to the form's class:
        private void Form1_Load(object sender, EventArgs e)
        {
            this.button1.Click += new System.EventHandler(this.button1_Click);
            this.FormClosing += new System.Windows.Forms.
                FormClosingEventHandler(this.Form1_FormClosing);
        }

        // You need this delegate in order to display text from a thread
        // other than the form's thread. See the HandleCallback
        // procedure for more information.
        // This same delegate matches both the DisplayStatus
        // and DisplayResults methods.
        private delegate void DisplayInfoDelegate(string Text);

        // This flag ensures that the user does not attempt
        // to restart the command or close the form while the
        // asynchronous command is executing.
        private bool isExecuting;

        // This example maintains the connection object
        // externally, so that it is available for closing.
        private SqlConnection connection;

        private static string GetConnectionString()
        {
            // To avoid storing the connection string in your code,
            // you can retrieve it from a configuration file.

            // If you have not included "Asynchronous Processing=true" in the
            // connection string, the command is not able
            // to execute asynchronously.
            return "Data Source=(local);Integrated Security=true;" +
                "Initial Catalog=AdventureWorks; Asynchronous Processing=true";
        }

        private void DisplayStatus(string Text)
        {
            this.label1.Text = Text;
        }

        private void DisplayResults(string Text)
        {
            this.label1.Text = Text;
            DisplayStatus("Ready");
        }

        private void Form1_FormClosing(object sender,
            System.Windows.Forms.FormClosingEventArgs e)
        {
            if (isExecuting)
            {
                MessageBox.Show(this, "Cannot close the form until " +
                    "the pending asynchronous command has completed. Please wait...");
                e.Cancel = true;
            }
        }

        private void button1_Click(object sender, System.EventArgs e)
        {
            if (isExecuting)
            {
                MessageBox.Show(this,
                    "Already executing. Please wait until the current query " +
                    "has completed.");
            }
            else
            {
                SqlCommand command = null;
                try
                {
                    DisplayResults("");
                    DisplayStatus("Connecting...");
                    connection = new SqlConnection(GetConnectionString());
                    // To emulate a long-running query, wait for
                    // a few seconds before working with the data.
                    // This command does not do much, but that's the point--
                    // it does not change your data, in the long run.
                    string commandText =
                        "WAITFOR DELAY '0:0:05';" +
                        "UPDATE Production.Product SET ReorderPoint = ReorderPoint + 1 " +
                        "WHERE ReorderPoint Is Not Null;" +
                        "UPDATE Production.Product SET ReorderPoint = ReorderPoint - 1 " +
                        "WHERE ReorderPoint Is Not Null";

                    command = new SqlCommand(commandText, connection);
                    connection.Open();

                    DisplayStatus("Executing...");
                    isExecuting = true;
                    // Although it is not required that you pass the
                    // SqlCommand object as the second parameter in the
                    // BeginExecuteNonQuery call, doing so makes it easier
                    // to call EndExecuteNonQuery in the callback procedure.
                    AsyncCallback callback = new AsyncCallback(HandleCallback);
                    command.BeginExecuteNonQuery(callback, command);
                }
                catch (Exception ex)
                {
                    isExecuting = false;
                    DisplayStatus(string.Format("Ready (last error: {0})", ex.Message));
                    if (connection != null)
                    {
                        connection.Close();
                    }
                }
            }
        }

        private void HandleCallback(IAsyncResult result)
        {
            try
            {
                // Retrieve the original command object, passed
                // to this procedure in the AsyncState property
                // of the IAsyncResult parameter.
                SqlCommand command = (SqlCommand)result.AsyncState;
                int rowCount = command.EndExecuteNonQuery(result);
                string rowText = " rows affected.";
                if (rowCount == 1)
                {
                    rowText = " row affected.";
                }
                rowText = rowCount + rowText;

                // You may not interact with the form and its contents
                // from a different thread, and this callback procedure
                // is all but guaranteed to be running from a different thread
                // than the form. Therefore you cannot simply call code that
                // displays the results, like this:
                // DisplayResults(rowText)

                // Instead, you must call the procedure from the form's thread.
                // One simple way to accomplish this is to call the Invoke
                // method of the form, which calls the delegate you supply
                // from the form's thread.
                DisplayInfoDelegate del = new DisplayInfoDelegate(DisplayResults);
                this.Invoke(del, rowText);
            }
            catch (Exception ex)
            {
                // Because you are now running code in a separate thread,
                // if you do not handle the exception here, none of your other
                // code catches the exception. Because none of
                // your code is on the call stack in this thread, there is nothing
                // higher up the stack to catch the exception if you do not
                // handle it here. You can either log the exception or
                // invoke a delegate (as in the non-error case in this
                // example) to display the error on the form. In no case
                // can you simply display the error without executing a delegate
                // as in the try block here.

                // You can create the delegate instance as you
                // invoke it, like this:
                this.Invoke(new DisplayInfoDelegate(DisplayStatus),
                    String.Format("Ready(last error: {0}", ex.Message));
            }
            finally
            {
                isExecuting = false;
                if (connection != null)
                {
                    connection.Close();
                }
            }
        }
    }
}
Imports System.Data.SqlClient

Public Class Form1
    ' Add this code to the form's class:
    ' You need this delegate in order to display text from a thread
    ' other than the form's thread. See the HandleCallback
    ' procedure for more information.
    ' This same delegate matches both the DisplayStatus 
    ' and DisplayResults methods.
    Private Delegate Sub DisplayInfoDelegate(ByVal Text As String)

    ' This flag ensures that the user does not attempt
    ' to restart the command or close the form while the 
    ' asynchronous command is executing.
    Private isExecuting As Boolean

    ' This example maintains the connection object 
    ' externally, so that it is available for closing.
    Private connection As SqlConnection

    Private Function GetConnectionString() As String
        ' To avoid storing the connection string in your code,            
        ' you can retrieve it from a configuration file. 

        ' If you have not included "Asynchronous Processing=true" in the
        ' connection string, the command is not able
        ' to execute asynchronously.
        Return "Data Source=(local);Integrated Security=true;" & _
          "Initial Catalog=AdventureWorks; Asynchronous Processing=true"
    End Function

    Private Sub DisplayStatus(ByVal Text As String)
        Me.Label1.Text = Text
    End Sub

    Private Sub DisplayResults(ByVal Text As String)
        Me.Label1.Text = Text
        DisplayStatus("Ready")
    End Sub

    Private Sub Form1_FormClosing(ByVal sender As Object, _
        ByVal e As System.Windows.Forms.FormClosingEventArgs) _
        Handles Me.FormClosing
        If isExecuting Then
            MessageBox.Show(Me, "Cannot close the form until " & _
                "the pending asynchronous command has completed. Please wait...")
            e.Cancel = True
        End If
    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles Button1.Click
        If isExecuting Then
            MessageBox.Show(Me, _
               "Already executing. Please wait until the current query " & _
                "has completed.")
        Else
            Dim command As SqlCommand
            Try
                DisplayResults("")
                DisplayStatus("Connecting...")
                connection = New SqlConnection(GetConnectionString())
                ' To emulate a long-running query, wait for 
                ' a few seconds before working with the data.
                ' This command does not do much, but that's the point--
                ' it does not change your data, in the long run.
                Dim commandText As String = _
                    "WAITFOR DELAY '0:0:05';" & _
                    "UPDATE Production.Product SET ReorderPoint = ReorderPoint + 1 " & _
                    "WHERE ReorderPoint Is Not Null;" & _
                    "UPDATE Production.Product SET ReorderPoint = ReorderPoint - 1 " & _
                    "WHERE ReorderPoint Is Not Null"

                command = New SqlCommand(commandText, connection)
                connection.Open()

                DisplayStatus("Executing...")
                isExecuting = True
                ' Although it is not required that you pass the 
                ' SqlCommand object as the second parameter in the 
                ' BeginExecuteNonQuery call, doing so makes it easier
                ' to call EndExecuteNonQuery in the callback procedure.
                Dim callback As New AsyncCallback(AddressOf HandleCallback)
                command.BeginExecuteNonQuery(callback, command)

            Catch ex As Exception
                isExecuting = False
                DisplayStatus(String.Format("Ready (last error: {0})", ex.Message))
                If connection IsNot Nothing Then
                    connection.Close()
                End If
            End Try
        End If
    End Sub

    Private Sub HandleCallback(ByVal result As IAsyncResult)
        Try
            ' Retrieve the original command object, passed
            ' to this procedure in the AsyncState property
            ' of the IAsyncResult parameter.
            Dim command As SqlCommand = CType(result.AsyncState, SqlCommand)
            Dim rowCount As Integer = command.EndExecuteNonQuery(result)
            Dim rowText As String = " rows affected."
            If rowCount = 1 Then
                rowText = " row affected."
            End If
            rowText = rowCount & rowText

            ' You may not interact with the form and its contents
            ' from a different thread, and this callback procedure
            ' is all but guaranteed to be running from a different thread
            ' than the form. Therefore you cannot simply call code that 
            ' displays the results, like this:
            ' DisplayResults(rowText)

            ' Instead, you must call the procedure from the form's thread.
            ' One simple way to accomplish this is to call the Invoke
            ' method of the form, which calls the delegate you supply
            ' from the form's thread. 
            Dim del As New DisplayInfoDelegate(AddressOf DisplayResults)
            Me.Invoke(del, rowText)

        Catch ex As Exception
            ' Because you are now running code in a separate thread, 
            ' if you do not handle the exception here, none of your other
            ' code catches the exception. Because none of your code
            ' is on the call stack in this thread, there is nothing
            ' higher up the stack to catch the exception if you do not 
            ' handle it here. You can either log the exception or 
            ' invoke a delegate (as in the non-error case in this 
            ' example) to display the error on the form. In no case
            ' can you simply display the error without executing a delegate
            ' as in the Try block here. 

            ' You can create the delegate instance as you 
            ' invoke it, like this:
            Me.Invoke(New DisplayInfoDelegate(AddressOf DisplayStatus), _
                String.Format("Ready(last error: {0}", ex.Message))
        Finally
            isExecuting = False
            If connection IsNot Nothing Then
                connection.Close()
            End If
        End Try
    End Sub
End Class

備註

方法 BeginExecuteNonQuery 會啟動異步執行 Transact-SQL 語句或未傳回數據列的預存程式的程式,讓其他工作可以在語句執行時同時執行。 當語句完成時,開發人員必須呼叫 EndExecuteNonQuery 方法來完成作業。 方法 BeginExecuteNonQuery 會立即傳回,但在程式代碼執行對應的 EndExecuteNonQuery 方法呼叫之前,它不得執行任何其他針對相同 SqlCommand 對象啟動同步或異步執行的呼叫。 EndExecuteNonQuery在命令的執行完成之前呼叫 ,會導致SqlCommand對象封鎖直到執行完成為止。

參數 callback 可讓您指定 AsyncCallback 語句完成時所呼叫的委派。 您可以從這個委派程式內,或從應用程式內的任何其他位置呼叫 EndExecuteNonQuery 方法。 此外,您可以在 參數中 asyncStateObject 傳遞任何物件,而回呼程式可以使用 屬性擷取這項資訊 AsyncState

請注意,命令文字和參數會同步傳送至伺服器。 如果傳送大型命令或許多參數,這個方法可能會在寫入期間封鎖。 傳送命令之後,方法會立即傳回,而不需要等候來自伺服器的答案,也就是讀取是異步的。

由於回呼程式是從 Microsoft .NET Common Language Runtime 所提供的背景線程內執行,因此您必須採取嚴格的方法來處理應用程式中的跨線程互動。 例如,您不得從回呼程式內與窗體的內容互動;如果必須更新表單,您必須切換回表單的線程,才能執行您的工作。 本主題中的範例示範此行為。

在作業執行期間發生的所有錯誤都會在回呼程式中擲回為例外狀況。 您必須在回呼程式中處理例外狀況,而不是在主應用程式中。 如需在回呼程式中處理例外狀況的其他資訊,請參閱本主題中的範例。

這個方法會 CommandTimeout 忽略 屬性。

另請參閱

適用於