C#•6mo ago

System.ArgumentNullException: Value cannot be null. (Parameter 's')

I wanted to create a new card view inserting images, names and review text etc as per short video attached.
The card view is not created but showed an exception instead:

System.ArgumentNullException: Value cannot be null. (Parameter 's')
   at System.ArgumentNullException.Throw(String paramName)
   at System.Text.Encoding.GetBytes(String s)
   at WebApplication1.Controllers.HomeController.CreateUser(ListingProjects_ver2 obModel)

System.ArgumentNullException: Value cannot be null. (Parameter 's')
   at System.ArgumentNullException.Throw(String paramName)
   at System.Text.Encoding.GetBytes(String s)
   at WebApplication1.Controllers.HomeController.CreateUser(ListingProjects_ver2 obModel)

`

And this exception seems to point this part in controller

public async Task <JsonResult> CreateUser([Bind("ListingName","Id","ListingReview")]ListingProjects_ver2 obModel) 
    {
        try
        {
            
            if (true)
            {
                
                if (obModel.ListingName == null)
                {
                    return new JsonResult(Problem());
                }

                //this bytecode points to the exception --- ListingImgName is set to null
                byte[] bytesListingImageName = Encoding.ASCII.GetBytes(obModel.ListingImgName);
                Upload(bytesListingImageName);
                _context.ListingVer2_DBTable.Add(obModel); 
           //more codes..

public async Task <JsonResult> CreateUser([Bind("ListingName","Id","ListingReview")]ListingProjects_ver2 obModel) 
    {
        try
        {
            
            if (true)
            {
                
                if (obModel.ListingName == null)
                {
                    return new JsonResult(Problem());
                }

                //this bytecode points to the exception --- ListingImgName is set to null
                byte[] bytesListingImageName = Encoding.ASCII.GetBytes(obModel.ListingImgName);
                Upload(bytesListingImageName);
                _context.ListingVer2_DBTable.Add(obModel); 
           //more codes..

`

I have no idea why it gets null. Any insights highly appreciated.

My full code for your reference https://pastesio.com/title-8921

Pastesio.com

title - Pastesio.com

SelfLess•6/19/25, 2:55 PM

I saw that code file.. actually its an exception,thus we should check for values , my suggestion is...add a debug point before:

at line 4..where '{' method starts and arguments have values..
or
at this line..

byte[] bytesListingImageName = Encoding.ASCII.GetBytes(obModel.ListingImgName);

SleepWellPupper•6/22/25, 6:22 AM

Looks like your model is not binding to the request as you expect it to. For one, you're not referencing the property in the list (in the constructor).
I assume ASP is thus simply ignoring the property when binding.