How switch between some connection in MVC

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hi i have some database and work with single mvc project and all of database are the same and all users register with this format( companyname/username)
when the user want login i get the databse and save in session
and when i want check the user is valid i get error:

System.ArgumentException: 'Keyword not supported: 'metadata'.'

What I have tried:

login:

public ActionResult Login(LoginViewModel login, string ReturnUrl = "")
       {

           string input = login.username.Trim();

           int index = input.IndexOf("/");
           if (index > 0)
               input = input.Substring(0, index);





           if (input == "Pub")
           {
               Session["_DBNAME_"] = "database name";

           }

using (databaseEntities dbo = new databaseEntities(Session["_DBNAME_"].ToString()))
          {

------------------------------------------------------------
dbcontext:

  public partial class databaseEntities : DbContext
    {
      

        public databaseEntities(string companyName)
      
        {
            string connString = ConfigurationManager.ConnectionStrings["databaseEntities"].ConnectionString;
            connString = connString.Replace("_DBNAME_", companyName);
            this.Database.Connection.ConnectionString = connString;

get error here:


        }

--------------------------------------------

webconfig:

 <connectionStrings>

<add name="databaseEntities" connectionString="metadata=res://*/Models.databaseModel.csdl|res://*/Models.databaseModel.ssdl|res://*/Models.databaseModel.msl;provider=System.Data.SqlClient;provider connection string="data source=.;initial catalog=_DBNAME_;user id=sa;password=pwd;multipleactiveresultsets=True;application name=EntityFramework"" providerName="System.Data.EntityClient" />

</connectionStrings>

Posted 18-Apr-20 21:00pm

mohamad_ali

Updated 19-Apr-20 0:48am

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2 solutions

Solution 2

mohamad_ali wrote:

...i want switch between some data base with one connection string , only replce database name

So, create default-connection:

HTML

<connectionStrings>
    <add name="defaultconnection" providerName="System.Data.SqlClient"
        connectionString="Server=ServerName\InstanceName; Database=CompanyA;User Id=sa;Password=pwd;" />
</connectionStrings>

So, create connstring "on-demand"

C#

namespace YourNameSpaceHere
{
    public class YourEntity: DbContext
    {
        private string connstring = string.Empty;
        public YourEntity(string _companyName) : base()
        {

            //get default connection string 
            connstring = ConfigurationManager.ConnectionStrings["defaultconnection"].ConnectionString;
            //returns:
            //"metadata=res://*/MyModel.csdl|res://*/MyModel.ssdl|res://*/MyModel.msl;data source=.;initial catalog=CompanyA;user id=sa;password=pwd;MultipleActiveResultSets=True;App=EntityFramework";
            Dictionary<string, string> connparts = GetConnParts(conn);
            connparts["initial catalog"] = _companyName;
            connstring = string.Join(";", connparts.Select(kvp=> $"{kvp.Key}={kvp.Value}"));
        }

	private Dictionary<string, string> GetConnParts(string sConnString)
	{
		return sConnString.Split(new string[]{";"}, StringSplitOptions.RemoveEmptyEntries)
			.Select(x=> new KeyValuePair<string, string>(x.Split('=')[0], x.Split('=')[1]))
			.ToDictionary(kvp=> kvp.Key, kvp=> kvp.Value);
	}


}

Note, that this method is not recommended!

Posted 19-Apr-20 0:49am

Maciej Los

Updated 19-Apr-20 4:45am

v4

Comments

mohamad_ali 19-Apr-20 7:03am

why, and which way is better?

Maciej Los 19-Apr-20 7:20am

The best way is to define as many connection strings as many companies, then get connection string by company name ;) - solution #1

mohamad_ali 19-Apr-20 10:05am

thnx for guidng me, but when the connection want opeen i got error

System.Data.Entity.Infrastructure.UnintentionalCodeFirstException: 'The context is being used in Code First mode with code that was generated from an EDMX file for either Database First or Model First development. This will not work correctly. To fix this problem do not remove the line of code that throws this exception. If you wish to use Database First or Model First, then make sure that the Entity Framework connection string is included in the app.config or web.config of the start-up project. If you are creating your own DbConnection, then make sure that it is an EntityConnection and not some other type of DbConnection, and that you pass it to one of the base DbContext constructors that take a DbConnection. To learn more about Code First, Database First, and Model First see the Entity Framework documentation here: http://go.microsoft.com/fwlink/?LinkId=394715'

Maciej Los 19-Apr-20 10:24am

OK. My mistake, because you did not provide information about Code First. You have to use your connection string, instead of mine. Using GetConnParts method you can re-build connection string.
[EDIT]
See updated answer ;)

mohamad_ali 19-Apr-20 10:50am

thnx alot ,the problem was solved

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Maciej Los · Accepted Answer · 2020-04-18T23:49:00

You're doing it wrong...

#1
If entity model is the same for each company, you have to define as many connections, as many companies (databases) you've got created:

XML

<connectionStrings>
    <add name="CompanyA" providerName="..." connectionString="..." />
    <add name="CompanyB" providerName="..." connectionString="..." />
</connectionStrings>

Your entity have to accept connection string as an input parameter:

C#

namespace YourNameSpaceHere
{
    public class YourEntity: DbContext
    {
        private string connstring = string.Empty;
        public YourEntity(string _companyName) : base()
        {

            //get connection string by company name
            connstring = ConfigurationManager.ConnectionStrings[_companyName].ConnectionString;
        }


}

#2
If entity model between companies is different, you have to define different entity for each company

C#

public Company1Context()
            : base("Company1") // connection string key
        {
            //define options here
        }

public Company2Context()
            : base("Company2") // connection string key
        {
            //define options here
        }