C# Function will work if i do not use async keyword

Question

Please see this function body and tell me does it work as asynchronously or synchronously ? Thanks

private Task<bool> SaveData(string xml)
{
 bool status = false;
 try
 {
 using (var con = new SqlConnection(ConnectionString))
 using (var cmd = new SqlCommand("USP_CSMAddTabTickerAndClientWise", con))
 using (var da = new SqlDataAdapter(cmd))
 {
 con.Open();
 cmd.CommandType = CommandType.StoredProcedure;
 cmd.Parameters.Add("@Xml", SqlDbType.Xml).Value = xml;
 status = (cmd.ExecuteNonQuery() > 0 ? true : false);
 }
 }
 catch (Exception ex)
 {
 status = false;
 MessageBox.Show("Error " + ex.Message);
 }

 return Task.FromResult(status);
}

string xml="sample data";
var task1 = SaveData(xml);
await Task.WhenAll(task1);
if ((bool)task1.Result)
{

}

EDIT

private async Task<bool> SaveData(string xml)
{
    bool status = false;
    try
    {
        using (var con = new SqlConnection(ConnectionString))
        using (var cmd = new SqlCommand("USP_CSMAddTabTickerAndClientWise", con))
        using (var da = new SqlDataAdapter(cmd))
        {
            con.Open();
            cmd.CommandType = CommandType.StoredProcedure;
            cmd.Parameters.Add("@Xml", SqlDbType.Xml).Value = xml;
            status = ( await cmd.ExecuteNonQueryAsync() > 0 ? true : false);
        }
    }
    catch (Exception ex)
    {
        status = false;
        MessageBox.Show("Error " + ex.Message);
    }

    return status;
}

var task1 = SaveData(xml);
await Task.WhenAll(task1);
if ((bool)task1.Result)
{

}

Now i restructure my code. new structure code would be consider & working as asynchronously ? please guide me. thanks

Answer 1

You would be better off with this pattern which is asynchronous and needs no WhenAll, Call it without creating a new instance of the class then the result can be deconstructed from the named value tuple for success/failure and if the exception is not null show exception.Message.

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

namespace Project1.Classes
{
    public class DataOperations
    {
        private static  string ConnectionString = "TODO";
        public static async Task<(bool success, Exception exception)> SaveData(string xml)
        {

            try
            {
                await using var con = new SqlConnection(ConnectionString);
                await using var cmd = new SqlCommand("USP_CSMAddTabTickerAndClientWise", con);
                using var da = new SqlDataAdapter(cmd);
                await con.OpenAsync();

                cmd.CommandType = CommandType.StoredProcedure;
                cmd.Parameters.Add("@Xml", SqlDbType.Xml).Value = xml;
                return ((await cmd.ExecuteNonQueryAsync() > 0), null);
            }
            catch (Exception ex)
            {
                return (false, ex);
            }
        }
    }
}

Answer 2

It's a synchronous method that wraps it's result in a Task that's usually used to propagate asynchronous results.

If you change your return type to bool and return this:

return status;

Instead of this:

return Task.FromResult(status);

Then the result will be the same. Then you can change the rest of your code to:

string xml="sample data";        
var result = SaveData(xml);
if (result)
{        

}