Entity framework Context.SaveChanges not working at all

Question

I'm having problems with this code. I´m able to connect to an mdf example database archive and generate the entity model. Althought I´m able to query the context model and retrieve information from the DB, when I try to update, delete or insert anything in the context and translate the changes to the DB Context.SaveChanges is not working. There is no Exception, the Entity model is updated properly, but the DB does not have the change. Thanks in regard

public void addCourse(int courseId, int deptId, string courseTitle)
{    
SchoolContexto = new SchoolEntities();            

Course mycourse= new Course();
mycourse.CourseID = courseId;
mycourse.Credits = 10;
mycourse.DepartmentID = deptId;
mycourse.Title = courseTitle;
SchoolContexto.Courses.Add(mycourse);            

SchoolContexto.SaveChanges();
SchoolContexto.Dispose();
}

Answer 1

Make property of .mdf file in your solution as Copy to output Directory: "Copy only if newer"

Otherwise your db file will overwrite every time it runs

Answer 2

Another way to add a new entity to the context is to change its state to Added. Have you tried this

using (var entities = new SchoolEntities()) 
{ 
    Course mycourse= new Course();
    mycourse.CourseID = courseId;
    mycourse.Credits = 10;
    mycourse.DepartmentID = deptId;
    mycourse.Title = courseTitle;
    context.Entry(mycourse).State = EntityState.Added;
    entities.SaveChanges(); 
}

Answer 3

i suggest you to use this code :

public void addCourse(int courseId, int deptId, string courseTitle)
{    
     SchoolEntities entities = new SchoolEntities();            

     Course mycourse= new Course();
     mycourse.CourseID = courseId;
     mycourse.Credits = 10;
     mycourse.DepartmentID = deptId;
     mycourse.Title = courseTitle;
     entities.Courses.Add(mycourse);            

     entities.SaveChanges();

 }

if this is not working i suggest you to check your app.config file :)