Display friendly error message on page without redirecting to Error.aspx

Question

_{Tuesday, March 8, 2011 5:40 AM}

Hi

All the examples and websites i have looked at redirect a user to the error.aspx page when an error occurs.

How do you just display a friendly error message on the page the user is viewing saying something like "Sorry unable to do whatever"

I've tried using a try catch block on my class that executes a stored procedure and put another try catch on the controller, but this does not work and i still get the default error message (System.InvalidOperationException was unhandled by user code)

My code is below:

 

public List<GetCurrencyDataFieldsFromDB> GetCurrencyDatabaseFields()
        {
            string spName = "dbo.******";
            using (SqlConnection cn = new SqlConnection(dbConn))
            {
                using (SqlCommand cmd = new SqlCommand(spName, cn))
                {
                    cmd.CommandType = CommandType.StoredProcedure;

                    List<G*****> CurrencyData = new List<G*****>();
                    try
                    {
                        cn.Open();
                        using (SqlDataReader rdr = cmd.ExecuteReader(CommandBehavior.SingleResult))
                        {
                            while (rdr.Read())
                            {
                                ****** GetData = new *******(
                                    (string)rdr["CurrencyID"],
                                    (string)rdr["Country"]);
                                CurrencyData.Add(GetData);
                            }
                            rdr.Close();
                        }
                        return CurrencyData;
                    }
                    catch (SqlException ex)
                    {
                        throw new ApplicationException(ex.Message);
                    }
                    finally
                    {
                        if (cn.State == ConnectionState.Open)
                        {  
                            cn.Close();  
                        }
                    }
                }
            }
        }

public ActionResult Index()
        {
            try
            {
                var ws = IGCD.******();
                this.ViewData["*****"] = new SelectList(ws.ToList(), "dboCurrencyID", "dboCountry");
                this.ViewData["*****"] = new SelectList(ws.ToList(), "dboCurrencyID", "dboCountry");
            }
            catch (Exception ex)
            {
                ViewData["SqlError"] = ex.Message;
                return View();
            }
            finally
            {

            }

            return View();
        }

So how can i just return ViewData["SqlError"] message in page

Regards

George

All replies (7)

_{Tuesday, March 8, 2011 9:12 AM ✅Answered}

what i need is to display an error on the page if the database is down when the page loads, before any user input.

Then make a try/catch in your action and in the catch add:

ModelState.AddModelError("", ex.Message)

---

_{Wednesday, March 9, 2011 5:58 AM ✅Answered}

1. Because ViewData does not allow compile time checking. Please see

http://msprogrammer.serviciipeweb.ro/2010/03/29/asp-net-mvc-orm-and-viewmodels/

2. This sort of errors  - if you continue with ViewData-  just with testing

---

_{Tuesday, March 8, 2011 8:24 AM}

ModelState.AddModelError("","my message")

Please follow MVC Music Store/NerdDinner tutorials

---

_{Tuesday, March 8, 2011 8:56 AM}

Hi Ignatandrei

All the examples i find including the ones in MVC Music Store/NerdDinner tutorials are related to invalid user input, what i need is to display an error on the page if the database is down when the page loads, before any user input.

I will have 3 partialviews on the page(if i can get them to work), if the one returning the currency data from the database is unable to get the data, i just want to display a message informing the user that they cannot check the currency rates at the moment.

Regards

George

---

_{Tuesday, March 8, 2011 10:03 AM}

Hi Ignatandrei

I have done that, but still get the same error, 'There is no ViewData item of type 'IEnumerable<SelectListItem>' that has the key 'ddlCurrencyConvertFrom'.' from my partialview

My code is below:

Going from Webforms to MVC is a huge learning curve, people say MVC is easy, but i find it to be anything but at the moment, and I have 5 books on MVC which is OK to read, but putting into my practice is another thing

<%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<IEnumerable<Web.Domain.Models.Currency.Entities.GetCurrencyDataFieldsFromDB>>" %>

<p>Currency Convertor</p>
<%: Html.DropDownList("ddlCurrencyConvertFrom", (SelectList)(ViewData["ddlCurrency"]),"Convert From")%>
<%: Html.DropDownList("ddlCurrencyConvertTo", (SelectList)(ViewData["ddlCurrency"]),"Convert To")%>
<%: Html.ValidationMessage("Unable to connect to db") %>


public ActionResult Index()
        {
            try
            {
                if (ModelState.IsValid)
                {
                    var ws = IGCD.GetCurrencyDatabaseFields();
                    this.ViewData["ddlCurrencyConvertFrom"] = new SelectList(ws.ToList(), "dboCurrencyID", "dboCountry");
                    this.ViewData["ddlCurrencyConvertTo"] = new SelectList(ws.ToList(), "dboCurrencyID", "dboCountry");
                }
            }
            catch (Exception ex)
            {
                ModelState.AddModelError("", ex.Message);
            }
            
            return View();
        }

 

Regards

George

---

_{Wednesday, March 9, 2011 3:20 AM}

There is no ViewData item of type 'IEnumerable<SelectListItem>' that has the key 'ddlCurrencyConvertFrom'.' from my partialview

This is a view error, not an action error. You did not pass a ViewData with ddlCurrencyConvertFrom

( did I mention that I hate ViewData?)

---

_{Wednesday, March 9, 2011 5:31 AM}

Hi Ignatandrei

Why do you hate viewdata?

Also how do i solve these sorts of errors?

Regards

George