C# code to me made better with Lambda expressions

I have a C# code that will perform CRUD operations on data into a grid view. I need to make it work with the lambda expressions. Please find the below code and help me further. I have no prior knowledge of regular expressions. I have given all the methods that need to be converted to Regular expressions and made better if possible at all angles. Please help me with this.

public IQueryable studentsGrid_GetData()
{
SchoolContext db = new SchoolContext();
var query = db.Students.Include(s => s.Enrollments.Select(e => e.Course));
return query;
}
// The id parameter name should match the DataKeyNames value set on the control
public void studentsGrid_UpdateItem(int id)
{
ContosoUniversityModelBinding.Models.Student item = null;
// Load the item here, e.g. item = MyDataLayer.Find(id);
if (item == null)
{
// The item wasn't found
ModelState.AddModelError("", String.Format("Item with id {0} was not found", id));
return;
}
TryUpdateModel(item);
if (ModelState.IsValid)
{
// Save changes here, e.g. MyDataLayer.SaveChanges();
}
}
public void studentsGrid_UpdateItem(int studentID)
{
using (SchoolContext db = new SchoolContext())
{
Student item = null;
item = db.Students.Find(studentID);
if (item == null)
{
ModelState.AddModelError("",
String.Format("Item with id {0} was not found", studentID));
return;
}
TryUpdateModel(item);
if (ModelState.IsValid)
{
db.SaveChanges();
}
}
}
public void studentsGrid_DeleteItem(int studentID)
{
using (SchoolContext db = new SchoolContext())
{
var item = new Student { StudentID = studentID };
db.Entry(item).State = EntityState.Deleted;
try
{
db.SaveChanges();
}
catch (DbUpdateConcurrencyException)
{
ModelState.AddModelError("",
String.Format("Item with id {0} no longer exists in the database.", studentID));
}
}
}