Custom Adding/Updating using Entity Framework 5

Introduction

Entity Framework is useful as an easy way for a developer to access, add, update and delete data for an application.

A developer can have a form with multiple fields and by calling code such as:

 private void usersBindingNavigatorSaveItem_Click(object sender, EventArgs e)
        {
            try
            {
                this.Validate();
                this.usersBindingSource.EndEdit();

                this.usersTableAdapter.Update(this.eko_payrollDataSet.users);
                this.eko_payrollDataSet.users.AcceptChanges();
                this.usersTableAdapter.Fill(this.eko_payrollDataSet.users);

                MessageBox.Show("User details updated successfully");                
            }
            catch (System.Exception ex)
            {
                System.Windows.Forms.MessageBox.Show(ex.Message);
            }
        }

He/she can easily be able to add this under the save button of the Windows nav bar for databound data.

Background

However, a developer may sometimes want to manipulate data for a certain field before adding or updating it to the database. E.g., hashing and encrypting a password before storage in a database.

Using the Code

The code below can be used for any other purpose apart from what is shown. It can be edited to suit a developers needs. Used when a user clicks on the navigation save button, the database will be changed accordingly either for adding or updating data.

GlobalClass.HashEncrypt is a method used on the password field.

private void usersBindingNavigatorSaveItem_Click(object sender, EventArgs e)
        {
            try
            {
                var users = entities.users.AsEnumerable().Where(x => x.Code.Equals(int.Parse(txtUsersCode.Text))).FirstOrDefault();

                if (users == null)
                {
                    user userToAdd = new user     // for adding
                    {
                        firstName = txtUsersFName.Text,
                        lastName = txtUsersLName.Text,
                        username = txtUsersUName.Text,
                        password = GlobalClass.HashEncrypt(txtUsersPassword.Text),
                        created = DateTime.Now,
                        companyAllocated = companyAllocatedComboBox.Text
                    };

                    entities.users.Add(userToAdd);
                    entities.SaveChanges();
                    this.usersTableAdapter.Fill(this.eko_payrollDataSet.users);
                }
                else   
                {
                    using (eko_enterpriseEntities ctx = new eko_enterpriseEntities())
                    {
                        var userToUpdate = ctx.users.Find(users.Code);

                        if (userToUpdate != null)   // for updating
                        {
                            userToUpdate.firstName = txtUsersFName.Text;
                            userToUpdate.lastName = txtUsersLName.Text;
                            userToUpdate.username = txtUsersUName.Text;
                            userToUpdate.password = GlobalClass.HashEncrypt(txtUsersPassword.Text);
                            userToUpdate.modified = DateTime.Now;
                            userToUpdate.companyAllocated = companyAllocatedComboBox.Text;

                            if (entities.Entry(userToUpdate).State == EntityState.Detached)
                            {
                                var entityKey = entities.users.Create().GetType().GetProperty("Code").GetValue(userToUpdate);
                                entities.Entry(entities.Set<user>().Find(entityKey)).CurrentValues.SetValues(userToUpdate);
                                entities.SaveChanges();
                                this.usersTableAdapter.Fill(this.eko_payrollDataSet.users);
                            }
                        }
                    }
                }
                MessageBox.Show("User details updated successfully");                
            }
            catch (System.Exception ex)
            {
                System.Windows.Forms.MessageBox.Show(ex.Message);
            }
        }

Points of Interest

I came up with this form after reading a few developer forum websites. Hope it may be of help to some.