Saving data read from sql database - c#-4.0

Question

I have four textboxes and a metrogrid, inside the textboxes data is read into them from sql database, but while saving the data in the textboxes one will save and others will vanish. Please i need help
this is the code for search button:
private void btnSearch_Click(object sender, EventArgs e)
{
try
{
using (SqlConnection connection = new SqlConnection(#"server = .\sql2012; database = dbAcceptance; integrated security = true; "))
{
SqlCommand command = new SqlCommand($"select * from acceptance WHERE regno = {txtregno.Text}", connection);
connection.Open();
SqlDataReader read = command.ExecuteReader();
if (read.Read())
{
txtfullname.Text = (read["fullname"].ToString());
txtdepartment.Text = (read["Department"].ToString());
txtfaculty.Text = (read["faculty"].ToString());
txtmodeofstudy.Text = (read["modeofstudy"].ToString());
txtprogramme.Text = (read["programmeofstudy"].ToString());
}
else
MetroFramework.MetroMessageBox.Show(this, "Reg No Not Found...Please Try Again", "Message");
read.Close();
}
}
catch (Exception ex)
{
//MetroFramework.MetroMessageBox.Show(this, ex.Message, "Message", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
}
This is the code for add button:
private void btnAdd_Click(object sender, EventArgs e)
{
objState = EntityState.Added;
pContainer.Enabled = true;
registeredBindingSource.Add(new Registered());
registeredBindingSource.MoveLast();
txtregno.Focus();
}
This is the code for the save button:
private void btnSave_Click(object sender, EventArgs e)
{
try
{
registeredBindingSource.EndEdit();
Registered obj = registeredBindingSource.Current as Registered;
if (obj != null)
{
using (IDbConnection db = new SqlConnection(ConfigurationManager.ConnectionStrings["conn"].ConnectionString))
{
if (db.State == ConnectionState.Closed)
db.Open();
if (objState == EntityState.Added)
{
DynamicParameters p = new DynamicParameters();
p.Add("#StudentID", dbType: DbType.Int32, direction: ParameterDirection.Output);
p.AddDynamicParams(new {
FullName = txtfullname.Text,
RegNo = txtregno.Text,
CourseTitle = obj.CourseTitle,
CourseStatus = obj.CourseStatus,
CourseUnit = obj.CourseUnit,
Department = txtdepartment.Text,
CurrentSemester = obj.CurrentSemester,
CurrentSession = obj.CurrentSession,
ModeOfStudy = txtmodeofstudy.Text,
Level = obj.Level,
ProgrammeOfStudy = txtprogramme.Text,
Faculty = txtfaculty.Text, finalSemester = obj.finalSemester
});
db.Execute("sp_StudentRegisteredCourse_insert", p, commandType: CommandType.StoredProcedure);
obj.StudentID = p.Get<int>("#StudentID");
}
else
{
db.Execute("sp_StudentRegisteredCourse_update", new { StudentID = obj.StudentID,FullName = txtfullname.Text,RegNo = txtregno.Text, CourseTitle = obj.CourseTitle,CourseStatus = obj.CourseStatus, CourseUnit = obj.CourseUnit, Department = txtdepartment.Text, CurrentSemester = obj.CurrentSemester,CurrentSession = obj.CurrentSession, ModeOfStudy = txtmodeofstudy.Text, Level = obj.Level, ProgrammeOfStudy = txtprogramme.Text,Faculty = txtfaculty.Text, finalSemester = obj.finalSemester },commandType:CommandType.StoredProcedure);
}
gridContainer.Refresh();
pContainer.Enabled = false;
objState = EntityState.unchanged;
}
}
}
catch (Exception ex)
{
MetroFramework.MetroMessageBox.Show(this, ex.Message, "Message", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
}