Question

Three class:

• CustomDbContext
• ReusableContext
• DbContext

Relation:

• ReusableContext : DbContext
• CustomDbContext : ReusableContext

Code:

public class ReusableDbContext : DbContext
{
    public ReusableDbContext() 
        : base("name = myConnectionString")
    {
        Database.SetInitializer＜ReusableDbContext＞(new 
MigrateDatabaseToLatestVersion＜ReusableDbContext, ReusableMigrationsConfiguration＞());
    }

    public DbSet＜ReusableTable＞ ReusableTables{ get; set; }
}

public class ReusableMigrationsConfiguration : DbMigrationsConfiguration＜ReusableDbContext＞
{
    public ReusableMigrationsConfiguration()
        : base()
    {
        AutomaticMigrationsEnabled = true;
        AutomaticMigrationDataLossAllowed = true;
    }

    protected override void Seed(ReusableDbContext context)
    {
        //ReusableMigrationsConfiguration Seed Logic here
        // this Seed method is never called  -----------  The Problem here!
    }
}

then i try to Reuse the ReusableContext like this:

public class CustomDbContext : ReusableDbContext
{
    public CustomDbContext() 
        : base()
    {
        Database.SetInitializer＜CustomDbContext＞(new 
MigrateDatabaseToLatestVersion＜CustomDbContext, CustomMigrationsConfiguration＞());
    }

    public DbSet＜CustomTable＞ CustomTables{ get; set; }
}

public class CustomMigrationsConfiguration : DbMigrationsConfiguration＜CustomDbContext＞
{
    public CustomMigrationsConfiguration()
        : base()
    {
        AutomaticMigrationsEnabled = true;
        AutomaticMigrationDataLossAllowed = true;
    }

    protected override void Seed(CustomDbContext context)
    {
        //CustomMigrationsConfiguration Seed Logic
        // this Seed method is called, no problem here
    }
}

after running the project:

• ReusableTable and CustomTable are created
• Seed Method of CustomMigrationsConfiguration is called and OK
• BUT, Seed Method of ReusableMigrationsConfiguration is NOT called ——– What is wrong?

Answer 1

Problem solved, here is the solution.

Class:

• CustomDbContext, CustomMigrationsConfiguration
• ReusableContext, ReusableMigrationsConfiguration＜TContext＞
• DbContext

Relation:

• ReusableContext : DbContext
• ReusableMigrationsConfiguration＜TContext＞ : DbMigrationsConfiguration＜TContext＞
  where TContext : ReusableContext
• CustomDbContext : ReusableContext
• CustomMigrationsConfiguration : ReusableMigrationsConfiguration＜CustomDbContext＞

Code:

public class ReusableDbContext : DbContext
{
    public ReusableDbContext() 
        : base("name = myConnectionString")
    {
        Database.SetInitializer＜ReusableDbContext＞(new 
MigrateDatabaseToLatestVersion＜ReusableDbContext, ReusableMigrationsConfiguration＞());
    }

    public DbSet＜ReusableTable＞ ReusableTables{ get; set; }
}

public class ReusableMigrationsConfiguration＜TContext＞ : DbMigrationsConfiguration＜TContext＞ where TContext : ReusableDbContext
{
    public ReusableMigrationsConfiguration()
        : base()
    {
        AutomaticMigrationsEnabled = true;
        AutomaticMigrationDataLossAllowed = true;
    }

    protected override void Seed(TContext context)
    {
        //ReusableMigrationsConfiguration Seed Logic here
        // is called and OK now.
    }
}

Now we can Reuse the ReusableContext like this:

public class CustomDbContext : ReusableDbContext
{
    public CustomDbContext() 
        : base()
    {
        Database.SetInitializer＜CustomDbContext＞(new 
MigrateDatabaseToLatestVersion＜CustomDbContext, CustomMigrationsConfiguration＞());
    }

    public DbSet＜CustomTable＞ CustomTables{ get; set; }
}

public class CustomMigrationsConfiguration : ReusableMigrationsConfiguration＜CustomDbContext＞
{
    public CustomMigrationsConfiguration()
        : base()
    {
        AutomaticMigrationsEnabled = true;
        AutomaticMigrationDataLossAllowed = true;
    }

    protected override void Seed(CustomDbContext context)
    {
        base.Seed(context);



        //CustomMigrationsConfiguration Seed Logic
        // this Seed method is called and OK
    }
}

after running the project:

• ReusableTable and CustomTable are created;
• Seed Method of CustomMigrationsConfiguration is called and OK;
• Seed Method of ReusableMigrationsConfiguration is called and OK too.

all things seem to be fine by now 🙂