CODEWITHSUNDEEP
c#entity-framework
Ahmed Abdo
Ahmed Abdo

Reputation: 77

Query using Entity Framework using input by textbox

I'm trying to query my database using Entity Framework, but I receive the following error:

System.NotSupportedException: 'LINQ to Entities does not recognize the method 'Int32 ToInt32(System.String)' method, and this method cannot be translated into a store expression.'

This is the relevant code part:

string gendercode = txtGenderNo.Text;

using (var dbcontext = new Entities())
{
    var GenderName = dbcontext
                     .Genders
                     .Where(u => u.Code == Convert.ToInt32(gendercode))
                     .Select(u => u.GenderType)
                     .SingleOrDefault();
    txtGenderName.Text = GenderName;
}

public int Code { get; set; }
public string GenderType { get; set; }

public virtual DbSet<Employee> Employees { get; set; }
public virtual DbSet<Gender> Genders { get; set; }
public virtual DbSet<sysdiagram> sysdiagrams { get; set; }

Upvotes: 0

Views: 984

Answers (2)

turanszkik
turanszkik

Reputation: 534

Convert your gendercode outside the query.

        string gendercode = txtGenderNo.Text;
        using (var dbcontext = new Entities())
        {
            var something = Convert.ToInt32(gendercode);
            var GenderName = dbcontext
                     .Genders
                     .Where(u => u.Code == something)
                     .Select(u => u.GenderType)
                     .SingleOrDefault();
            txtGenderName.Text = GenderName;
        }

It should work this way.

Upvotes: 1

germi
germi

Reputation: 4658

Entity Framework tries to translate your C# code into SQL. Not everything is translatable - only a certain subset is supported by the Entity Framework driver. In your case the solution is easy: convert genderCode to int before the LINQ query and use that value in the query:

var genderCodeAsInt = Convert.ToInt32(gendercode);
using (var dbcontext = new Entities())
{
    var GenderName = dbcontext
                     .Genders
                     .Where(u => u.Code == genderCodeAsInt)
                     .Select(u => u.GenderType)
                     .SingleOrDefault();
            txtGenderName.Text = GenderName;
}

Upvotes: 4

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