Question

I have a project that uses MVC 3 and Entity Franework. The site works fine on my local machine, but when publishing to a server I get the following error:

Unable to find the requested .Net Framework Data Provider.  It may not be installed.

I have done some research and it seems the db provider factory is not registered. I have tried to include System.Data.Entity as copy local. However this did not work.

Here is my connection string:

<add name="SurveyEntities" connectionString="metadata=res://*/Models.Database.csdl|res://*/Models.Database.ssdl|res://*/Models.Database.msl;provider=System.Data.SqlClient;provider connection string=&quot;Data Source=websvr-new;Initial Catalog=Survey;Persist Security Info=True;User ID=SurveyUser;Password=5urv3yu5er;MultipleActiveResultSets=True&quot;" providerName="System.Data.EntityClient" />

I have seen a few possible solutions but most relate to SqLite.

Answer 1

The problem turned out to be a broken machine.config file on our server. Some other db provider’s installer created a second section causing the error. The underlying error only become visible when creating a controller method that enumerates the Provider class factories. The following controller method helped diagnose the problem:

   public string provider()
        {
            string rs = "<table>";
            DataTable dt =  System.Data.Common.DbProviderFactories.GetFactoryClasses();
            foreach (DataRow row in dt.Rows)
            {
                rs += "<tr>";
                foreach (DataColumn COL in dt.Columns)
                {
                    rs += "<td>";
                    rs += ((string)row[COL]) ;
                    rs += "</td>";
                }
                rs += "</tr>";
            }
            rs += "</table>";
            return rs;
        }