CODEWITHSUNDEEP
asp.netsql-serverasp.net-mvcentity-framework
Muhammad Ehsan Mirzaei
Muhammad Ehsan Mirzaei

Reputation: 129

NullException error in MVC first code entity

I have MVC first code project but I get below error error pic

First code! So there is no default database.

Model class

public class Applicant
{
    public int ApplicantID { get; set; }
    public string UserName { get; set; }
    public string Password { get; set; }
    public int PhoneNumber { get; set; }
}

Context class:

public class Context : DbContext
{
    public List<Applicant> Applicants { get; set; }
    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Applicant>().Property(r => r.ApplicantID)
                     .HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);
    }
}

Applicant repasority class:

public  Applicant Create(string username, string password, int phoneNumber, out int existResult)
{
    if (context.Applicants.Where(x => x.UserName == username).ToString() != null)
    {
        applicant = new Applicant()
        {
            UserName = username,
            Password = password,
            PhoneNumber = phoneNumber,
        };
        context.Applicants.Add(applicant);
        existResult = 1;
        return applicant;
    }
    existResult = 0;
    return applicant;   
}

And I added below code to my web.config in my web solution:

  <connectionStrings>
    <add connectionString="Data Source=.;Catalog=Homi;Integrated Security=True" providerName="System.Data.SqlClient" name="Context" />
 </connectionStrings>
</configuration>

Upvotes: 0

Views: 50

Answers (1)

Muhammad Ehsan Mirzaei
Muhammad Ehsan Mirzaei

Reputation: 129

ok I find answer.

first I changed context class to this like below

add this part:

public Context()
    {
        base.Configuration.LazyLoadingEnabled = false;
        base.Configuration.ProxyCreationEnabled = false;
        base.Configuration.ValidateOnSaveEnabled = false;
    }

and changed string to DbSet:

    public DbSet<Applicant> Applicants { get; set; }

second

a cool mistake :D I forgot to do this:

Project –> Manage NuGet Packages…

Note: If you don’t have the Manage NuGet Packages… option you should install the latest version of NuGet

Select the Online tab

Select the EntityFramework package

Click Install

after all for some place of code if above ways doesn't work try{}catch{} was last solution!

and in end when I run my web nothing saved in my db :( it was very important to put "context.SaveChanges();" in applicant repository after "context.Add(applicant);"

that's all tnx

Upvotes: 1

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