How To use ExecuteSqlCommandAsync

.net, async-await, asynchronous, c#, entity-framework

Solution

Your code is fine. It just needs to be inside an `async` method:

public async Task FooAsync()
{
    if (OldMarketRightsIDs.Count > 0)
    {
        TaskReturn = Data.MK3Model.Database.ExecuteSqlCommandAsync("DELETE FROM TitleMarketRights WHERE ID in (" + string.Join(", ", OldMarketRightsIDs) + ")");
    }

    var NewMarketRights = MarketRights.Select(m => new
    {
        Key = m.Key,
        Value = m.Value.Except(CurrentMarketRights[m.Key].Select(c => c.FK_ProductRight).ToList())
    }).ToList();

    foreach (var mr in NewMarketRights)
    {
        foreach (var ProdID in mr.Value)
        {
            Data.MK3Model.TitleMarketRights.Add(new TitleMarketRight { FK_MarketID = (mr.Key == 0) ? null : (int?)mr.Key, FK_TitleID = ID, FK_ProductRight = ProdID });
        }
    }

    var i = await TaskReturn;
}

That's what allows you to use `await`. Behind the scenes a state machine is built that handles the asynchronous nature of you method. The method needs to have the `async` keyword and return a `Task` or `Task<T>` if you have a return value.

If you would want to have it as a lambda expression then:

Func<Task> fooAsync = async () =>
{
    if (OldMarketRightsIDs.Count > 0)
    {
        TaskReturn = Data.MK3Model.Database.ExecuteSqlCommandAsync("DELETE FROM TitleMarketRights WHERE ID in (" + string.Join(", ", OldMarketRightsIDs) + ")");
    }

    var NewMarketRights = MarketRights.Select(m => new
    {
        Key = m.Key,
        Value = m.Value.Except(CurrentMarketRights[m.Key].Select(c => c.FK_ProductRight).ToList())
    }).ToList();

    foreach (var mr in NewMarketRights)
    {
        foreach (var ProdID in mr.Value)
        {
            Data.MK3Model.TitleMarketRights.Add(new TitleMarketRight { FK_MarketID = (mr.Key == 0) ? null : (int?)mr.Key, FK_TitleID = ID, FK_ProductRight = ProdID });
        }
    }

    var i = await TaskReturn;
};

var task = fooAsync();

Problem

I've been trying to figure out `ExecuteSqlCommandAsync`, which I haven't been able to find any good documentation on. ``` if (OldMarketRightsIDs.Count > 0) { //This is where I want to have the task Begin TaskReturn = Data.MK3Model.Database.ExecuteSqlCommandAsync("DELETE FROM TitleMarketRights WHERE ID in (" + string.Join(", ", OldMarketRightsIDs) + ")"); } //This is the Code I want To execute in between var NewMarketRights = MarketRights.Select(m => new { Key = m.Key, Value = m.Value.Except(CurrentMarketRights[m.Key].Select(c => c.FK_ProductRight).ToList()) }).ToList(); foreach (var mr in NewMarketRights) { foreach (var ProdID in mr.Value) { Data.MK3Model.TitleMarketRights.Add(new TitleMarketRight { FK_MarketID = (mr.Key == 0) ? null : (int?)mr.Key, FK_TitleID = ID, FK_ProductRight = ProdID }); } } //This is where I want to wait until the task is complete before continuing var i = await TaskReturn; ``` This Example doesn't compile, it gets an error await operator can only be used with an async Method. Any Ideas on how to get this working

Original source