Exception handling in Entity Framework

Question

I have a form that it has some field and has relationship with database. I'm using entity framework I wanna handle exception before sql server send error message. For example when user enter string value in number field win or web application handle exception before sql server handle it. I wrote this code but it don't work for all the exception. For example if field was empty or has invalid type said input string is not in correct format.

 using (var context  = new entityTestEntities2())
        {
            try
            {
                int stNumber = Convert.ToInt32(textBox2.Text);
                var allCustomers = context.setcust(null, stNumber);
            }
            catch(Exception ex)
            {
                if (ex.Message.Contains("correct format"))
                { 
                int x= System.Runtime.InteropServices.Marshal.GetExceptionCode();
                     MessageBox.Show("error number"+x.ToString()+ex.Message);
                }
             }
        }

my question is general its only an example (int or empty field) — heavy
– heavy, Commented Nov 16, 2013 at 5:36
What does the UI look like? We're using MVC3 a lot lately, we'll build out datamodels with attributes and/or use the unobtrusive javascript validation. I'd think you'd want to do validation closer to the UI instead of letting it make a call to the database, especially in a web environment. — Jake Hargus
– Jake Hargus, Commented Nov 16, 2013 at 5:59
i do it with java script in web app but i want to produce core and place exception handle in core.i wanna find a solution for it — heavy
– heavy, Commented Nov 16, 2013 at 6:08
Validation in EF: msdn.microsoft.com/en-gb/data/gg193959.aspx MVC uses Data Annotations on Entities to support jQuery unobtrusive validation stackoverflow.com/questions/11534910/… — Colin
– Colin, Commented Nov 18, 2013 at 10:22

General Grievance · Accepted Answer · 2025-10-07 20:08:55Z

You should do validation on the UI first then handle specific errors related to Entity Framework.

Create a Model and use data annotations :

using System.ComponentModel.DataAnnotations;
public class YourViewModel
    {
        [Required]
        [Range(0, 15, ErrorMessage = "Can only be between 0 .. 15")]
        public int stNumber { get; set; }
    }

In your controller return the model to the view:

var model = new YourViewModel();
return View(model);

Bind your textbox to the model by adding the model to your view and using some tag helpers:

@using YourProject.WebUI.Models
@model YourViewModel  

@Html.TextBoxFor(m => m.stNumber )
@Html.ValidationMessageFor(m => m.stNumber )

Now when someone tries to enter a non numeric or a number that is out of range an error will be displayed to the user before bad data is ever sent back to the controller.

To handle Entity Framework exceptions use a try catch:

        try
        {
            var entity = context.yourEntity.FirstOrDefault(o => o.Id == custId);

            if (entity == null) return false;
            entity.value= stNumber;
            entity.ModifiedBy = userId;
            entity.ModifiedDate = DateTime.Now;
            Db.SaveChanges();
            return true;
        }
        catch (DbUpdateException Ex)
        {
            Console.WriteLine(Ex.InnerException.Message);
            return false;
        }

Other Exception types include (from here):

DbUpdateException An error occurred sending updates to the database.

DbUpdateConcurrencyException A database command did not affect the expected number of rows. This usually indicates an optimistic concurrency violation; that is, a row has been changed in the database since it was queried.

DbEntityValidationException The save was aborted because validation of entity property values failed.

NotSupportedException An attempt was made to use unsupported behavior such as executing multiple asynchronous commands concurrently on the same context instance.

ObjectDisposedException The context or connection have been disposed.

InvalidOperationException Some error occurred attempting to process entities in the context either before or after sending commands to the database.

Yusuf Uzun · Accepted Answer · 2013-11-17 20:30:05Z

What you should do is finding a architecture which is fits your solution model. In general I would do validation before creating the context. If you need more validation in your application you may want to create a validation layer for this purpose.

public class RuleViolation
{
    public string Property {get; set;}
    public string Message {get; set;}
}

public class Program
{
    public static List<RuleViolation> GetRuleViolations(string[] parameters)
    {
        List<RuleViolation> validations = new List<RuleViolation>();

        if(!int.TryParse(parameters[0], out new Int32()))
        {
            validations.Add(new RuleViolation{Message ="Input1 must be integer.", Property = "input1"});
        }
        //more validation

        return validations;
    }

    public static void Main(string[] parameters)
    {
        var validations = GetRuleViolations(parameters);

        if(validations.Any())
        {
            validations.ForEach(x=> Console.WriteLine(x.Message));
            return;
        }

        int input1 = int.Parse(parameters[0]);

        //after all your business logic are ok, then you can go to persistence layer to hit the database.
        using (var context  = new entityTestEntities2())
        {
            try
            {
                var allCustomers = context.setcust(null, input1);
            }
            catch(SqlException exc)
            {
                //here you might still get some exceptions but not about validation.

                ExceptionManager.Log(exc);

                //sometimes you may want to throw the exception to upper layers for handle it better over there!
                throw;
            }
        }
    }
}

Hope the example make more clearer the architecture about validation logic.

Shiraz Bhaiji · Accepted Answer · 2014-01-24 13:14:49Z

5

Instead of catching Exception you should catch SqlException.

SqlException has a number property that you can use:

catch (SqlException e)
{
   MessageBox.Show("Error number: "+e.Number + " - " + e.Message);
}

edited Jan 24, 2014 at 13:14

answered Nov 17, 2013 at 20:16

Shiraz Bhaiji

65.7k37 gold badges149 silver badges260 bronze badges

Collectives™ on Stack Overflow

Exception handling in Entity Framework

3 Answers 3

Comments

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related