Convert existing C# synchronous method to asynchronous with async/await?

Question

Starting with a synchronous I/O bound method (below), how do I make it asynchronous using async/await?

public int Iobound(SqlConnection conn, SqlTransaction tran)
{
    // this stored procedure takes a few seconds to complete
    SqlCommand cmd = new SqlCommand("MyIoboundStoredProc", conn, tran);
    cmd.CommandType = CommandType.StoredProcedure;

    SqlParameter returnValue = cmd.Parameters.Add("ReturnValue", SqlDbType.Int);
    returnValue.Direction = ParameterDirection.ReturnValue;
    cmd.ExecuteNonQuery();

    return (int)returnValue.Value;
}

MSDN examples all presume the preexistence of an *Async method and offer no guidance for making one yourself for I/O-bound operations.

I could use Task.Run() and execute Iobound() within that new Task, but new Task creation is discouraged since the operation is not CPU-bound.

I'd like to use async/await but I'm stuck here on this fundamental problem of how to proceed with the conversion of this method.

do a google search , there are actually plenty of examples on how to decorate your method to be await as well as use Task<> — MethodMan
@CamiloTerevinto may I ask you why you constantly editing formatting of my answer? Position of { (on new line or not) is personal preference and changing it does not add any value. — Evk
@Evk It's not personal preference if there's a difference between being able to read and having to scroll — Camilo Terevinto

Evk Evk · Accepted Answer · 2017-11-26T19:47:22

Conversion of this particular method is pretty straight-forward:

// change return type to Task<int>
public async Task<int> Iobound(SqlConnection conn, SqlTransaction tran) 
{
    // this stored procedure takes a few seconds to complete
    using (SqlCommand cmd = new SqlCommand("MyIoboundStoredProc", conn, tran)) 
    {
        cmd.CommandType = CommandType.StoredProcedure;
        SqlParameter returnValue = cmd.Parameters.Add("ReturnValue", SqlDbType.Int);
        returnValue.Direction = ParameterDirection.ReturnValue;
        // use async IO method and await it
        await cmd.ExecuteNonQueryAsync();
        return (int) returnValue.Value;
    }
}

Convert existing C# synchronous method to asynchronous with async/await?

1 Answers