SqlConnectionStringBuilder.AsynchronousProcessing Property


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Gets or sets a Boolean value that indicates whether asynchronous processing is allowed by the connection created by using this connection string.

Namespace:   System.Data.SqlClient
Assembly:  System.Data (in System.Data.dll)

public bool AsynchronousProcessing { get; set; }

Property Value

Type: System.Boolean

This property is ignored beginning in .NET Framework 4.5. For more information about SqlClient support for asynchronous programming, see Asynchronous Programming.

The value of the AsynchronousProcessing property, or false if no value has been supplied.

This property corresponds to the "Asynchronous Processing" and "async" keys within the connection string. In order to take advantage of the asynchronous processing provided by the SqlCommand object, this key/value pair must be included within the connection string of the associated SqlConnection object.

The following example retrieves a connection string and verifies that the connection string is configured to allow for asynchronous processing. (In this case, the string comes from a procedure within the application, but in a production application, the connection string might come from a configuration file, or some other source.) Then, the example performs an asynchronous operation, updating values within a sample database on a background thread.

using System.Data.SqlClient;
using System.Threading;

class Program
    static void Main()
        // Create a SqlConnectionStringBuilder instance, 
        // and ensure that it is set up for asynchronous processing.
        SqlConnectionStringBuilder builder =
            new SqlConnectionStringBuilder(GetConnectionString());
        // Asynchronous method calls won't work unless you
        // have added this option, or have added
        // the clause "Asynchronous Processing=true"
        // to the connection string.
        builder.AsynchronousProcessing = true;

        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, builder.ConnectionString);

        Console.WriteLine("Press any key to finish.");

    private static string GetConnectionString()
        // To avoid storing the connection string in your code,
        // you can retrieve it from a configuration file. 
        return "Data Source=(local);Integrated Security=SSPI;" +
            "Initial Catalog=AdventureWorks";

    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's working, verifying the 
        // asynchronous behavior. 
        using (SqlConnection connection = new SqlConnection(connectionString))
                int count = 0;
                SqlCommand command = new SqlCommand(commandText, connection);
                IAsyncResult result = command.BeginExecuteNonQuery();
                while (!result.IsCompleted)
                    Console.WriteLine("Waiting {0}.", count);
                    // Wait for 1/10 second, so the counter
                    // doesn't consume all available resources 
                    // on the main thread.
                    count += 1;
                Console.WriteLine("Command complete. Affected {0} rows.",

            catch (SqlException ex)
                    "Error {0}: System.Data.SqlClient.SqlConnectionStringBuilder", 
                    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);

.NET Framework
Available since 2.0
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