Overriding code-generated DbContext constructor

Question

I\'m sure I\'ve done this before at some stage, but I can\'t figure out how to now! My scenario:

// This is generated from EDMX
public partial class HOLDbEnt         


        

Answer 1

Here is my solution to the problem. I edit the TT file as Dylan Hayes suggested and replaced the constructor with my own. In my case, i needed to change the schema names of certain schemas only. I set a variable in the config file to tell me what environment I was in and used the right schema.

using System.Configuration;
using System.Data.Entity;
using System.Data.Entity.Core.Mapping;
using System.Data.Entity.Core.Metadata.Edm;
using System.Data.Entity.Core.Objects;
using System.Data.Entity.Infrastructure;
using System.Reflection;
using System.Xml;

namespace WS.Framework.WSJDEData
{

    public partial class WSJDE : DbContext
    {
        public WSJDE()
            : base("name=WSJDE")
        {
            ObjectContext context = (this as IObjectContextAdapter).ObjectContext;

            string environment = ConfigurationManager.AppSettings.Get("Environment");

            const string devCTL = "TESTCTL";
            const string devDTA = "TESTDTA";
            const string qaCTL = "CRPCTL";
            const string qaDTA = "CRPDTA";
            const string prodCTL = "PRODCTL";
            const string prodDTA = "PRODDTA";

            var x = Assembly.GetExecutingAssembly().GetManifestResourceStream("WSJDEData.WSJDE.ssdl");

            XmlReader[] sReaders = new XmlReader[]
                {
                    XmlReader.Create(Assembly.GetExecutingAssembly().GetManifestResourceStream("WSJDEData.WSJDE.ssdl"))
                };

            XmlReader[] mReaders = new XmlReader[]
                {XmlReader.Create(Assembly.GetExecutingAssembly().GetManifestResourceStream("WSJDEData.WSJDE.msl"))};

            StoreItemCollection sCollection = new StoreItemCollection(sReaders);

            ObjectContext objContext = ((IObjectContextAdapter) context).ObjectContext;
            MetadataWorkspace workspace = objContext.MetadataWorkspace;

            EdmItemCollection cCollection = workspace.GetItemCollection(DataSpace.CSpace) as EdmItemCollection;


            StorageMappingItemCollection csCollection = new StorageMappingItemCollection(cCollection, sCollection,
                                                                                         mReaders);

            workspace.RegisterItemCollection(sCollection);
            workspace.RegisterItemCollection(csCollection);

            EntityContainer container = workspace.GetItem("WSJDEModelStoreContainer", DataSpace.SSpace);

            foreach (EntitySetBase entitySetBase in container.BaseEntitySets)
            {
                string schema = entitySetBase.Schema;

                if (schema != null)
                {
                    string name = schema.Substring(schema.Length - 3);

                    if (name == "CTL")
                    {
                        switch (environment)
                        {
                            case "Dev":
                                typeof (EntitySetBase).GetField("_schema",
                                                                BindingFlags.NonPublic | BindingFlags.Instance)
                                                      .SetValue(entitySetBase, devCTL);
                                break;
                            case "QA":
                                typeof (EntitySetBase).GetField("_schema",
                                                                BindingFlags.NonPublic | BindingFlags.Instance)
                                                      .SetValue(entitySetBase, qaCTL);
                                break;
                            case "Prod":
                                typeof (EntitySetBase).GetField("_schema",
                                                                BindingFlags.NonPublic | BindingFlags.Instance)
                                                      .SetValue(entitySetBase, prodCTL);
                                break;

                        }
                    }

                    if (name == "DTA")
                    {
                        switch (environment)
                        {
                            case "Dev":
                                typeof (EntitySetBase).GetField("_schema",
                                                                BindingFlags.NonPublic | BindingFlags.Instance)
                                                      .SetValue(entitySetBase, devDTA);
                                break;
                            case "QA":
                                typeof (EntitySetBase).GetField("_schema",
                                                                BindingFlags.NonPublic | BindingFlags.Instance)
                                                      .SetValue(entitySetBase, qaDTA);
                                break;
                            case "Prod":
                                typeof (EntitySetBase).GetField("_schema",
                                                                BindingFlags.NonPublic | BindingFlags.Instance)
                                                      .SetValue(entitySetBase, prodDTA);
                                break;

                        }
                    }
                }
            }
        }
    }
}