C#

I am trying to work on Audio file and have seconds as int in C#, but I would like to convert seconds into hh:mm:ss ( hours, minutes and seconds) format, so How can I do it easily in C#?

For example: 20 Seconds = 00:00:20 in hour,minutes,seconds format.

Hello, I am using the below code to fetch some data from database and getting the error "Sequence contains no elements"

 public static IEnumerable<CompanyLicenseKey> GetCompanyLicenseKey()
{
            OPEntities onepassDB = new OPEntities();

            //Let's get the onepass User model first
            var user = onepassDB.UserAccounts.Where(x => x.Email == OnePassUserAccountEmail).First(); //error in this line

            var userLicenseList = from c in user.CompanyProfiles
                                  join l in onepassDB.CompanyLicenseKeys.Where(x => x.IsDisabled == false)
                                  .Select(x => new { x.CRMID, x.LicenseKey, x.FriendlyName, x.ProductName })
                                  on new { c.CRMID } equals new { l.CRMID }
                                  select new Models.OnePass.CompanyLicenseKey { LicenseKey = l.LicenseKey, FriendlyName = l.FriendlyName, ProductName = l.ProductName };

            if (ProductName == "")
                return userLicenseList.ToList().OrderBy(x => x.FriendlyName);
            else
                return userLicenseList.Where(x => x.ProductName == ProductName).ToList().OrderBy(x => x.FriendlyName);
        }

Error image

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I am trying to create and Instantiate IQueryable<T> object in my C# MVC project, but I am not able to create it, I would like to use it instead of List<T> = new List<T>, so how can I do it? I am trying this

I am trying to convert JSON object into C# class object, Using a really simple test case:

I am trying to optimise my query to get data from database, so I would to know how can I directly run a sql query in my C#.

Currently I am using Entity framework with EDMX, so to improve query time, I would like to know how can I run direct sql query?

How can i validate TinyMCE using asp.net MVC and razor? Currently, i was trying to validate it using Model validations but it is not working and not showing any errors even when TinyMCE textarea is blank, so how can i validate it? here is my javascript code

I am trying to convert List into JSON format using the code below