Как выбрать заказы с одинаковыми номерами sku и qty?

Проверьте эту ссылку, где описано: http://msdn.microsoft.com/en-us/library/vstudio/hh191443.aspx

async Task TaskOfTResult_MethodAsync()
{
    int hours;
    // . . .
    // The body of the method should contain one or more await expressions.

    // Return statement specifies an integer result.
    return hours;
}

    // Calls to TaskOfTResult_MethodAsync from another async method.
private async void CallTaskTButton_Click(object sender, RoutedEventArgs e)
{
    Task returnedTaskTResult = TaskOfTResult_MethodAsync();
    int intResult = await returnedTaskTResult;
    // or, in a single statement
    //int intResult = await TaskOfTResult_MethodAsync();
}






// Signature specifies Task
async Task Task_MethodAsync()
{
    // . . .
    // The body of the method should contain one or more await expressions.

    // The method has no return statement.  
}

    // Calls to Task_MethodAsync from another async method.
private async void CallTaskButton_Click(object sender, RoutedEventArgs e)
{
    Task returnedTask = Task_MethodAsync();
    await returnedTask;
    // or, in a single statement
    //await Task_MethodAsync();
}