public async Task <IActionResult> PutStudent2(int id, Student2 student2)
{
if (id != student2.Id)
{
return(BadRequest());
}
_context.Entry(student2).State = EntityState.Modified;
try
{
await _context.SaveChangesAsync();
}
catch (DbUpdateConcurrencyException)
{
if (!Student2Exists(id))
{
return(NotFound());
}
else
{
throw;
}
}
return(NoContent());
}
public async Task <ActionResult <Student2> > PostStudent2(Student2 student2)
{
_context.Students2.Add(student2);
await _context.SaveChangesAsync();
return(CreatedAtAction("GetStudent2", new { id = student2.Id }, student2));
}
/// <summary>
/// 查询测试
/// </summary>
/// <param name="p"></param>
/// <param name="d"></param>
private void Select(Student2 p, SqlSugarClient db)
{
//查询第一条
var select1 = db.Queryable <Student>().Single(it => it.id == p.id);
var select2 = db.Queryable <Student>().Single(it => it.id == _p.id);
//查询分页 id3-id5
var select3 = db.Queryable <Student>().OrderBy(it => it.id).Skip(2).Take(3).ToList();
//查询分页 id4-id6
var select4 = db.Queryable <Student>().OrderBy(it => it.id).ToPageList(2, 3).ToList();
//2表join
var join1 = db.Queryable <Student>().JoinTable <School>((st, sc) => st.sch_id == sc.id)
.Select <School, V_Student>((st, sc) => new V_Student()
{
SchoolName = sc.name, id = st.id, name = st.name
}).ToList();
//3表join
var join2 = db.Queryable <Student>()
.JoinTable <School>((st, sc) => st.sch_id == sc.id)
.JoinTable <School, Area>((st, sc, a) => sc.AreaId == a.id)
.Select <School, Area, V_Student>((st, sc, a) => new V_Student()
{
SchoolName = sc.name, id = st.id, name = st.name, AreaName = a.name
}).ToList();
}
public void Init()
{
Student2 p = new Student2()
{
id = 2, name = "张表", isOk = true
};
Console.WriteLine("启动Test.Init");
using (var db = SugarDao.GetInstance())
{
//初始化数据
InitData(db);
//查询测试
Select(p, db);
//拉姆达测试
Exp(p, db);
//新容器转换测试
SelectNew(p, db);
//更新测试
Update(p, db);
//删除测试
Delete(p, db);
}
}
/// <summary>
/// 批量更新
/// </summary>
/// <param name="p"></param>
/// <param name="db"></param>
private void Update(Student2 p, SqlSugarClient db)
{
db.UpdateRange(StudentListUpd);
var list = db.Queryable <Student>().ToList();
db.SqlBulkReplace(StudentListUpd2);
list = db.Queryable <Student>().ToList();
}
public static void Main(string[] args)
{
Student2 s2 = new Student2();
s2.id2 = 104;
s2.name2 = "Jane Doe \n";
Console.WriteLine(s2.id2);
Console.WriteLine(s2.name2);
}
private void button2_Click(object sender, EventArgs e)
{
Student2 stu2 = DDD.getStudentObject(user);
Form12 form12 = new Form12(ref DDD, user);
string s = stu2.firstName + " " + stu2.middleName + " " + stu2.lastName;
form12.ChangeLabelName(s);
form12.ShowDialog();
}
//[Route("api/v2/students/{id}")]
public IHttpActionResult Get(int id)
{
Student2 student = students.FirstOrDefault(s => s.ID == id);
if (student == null)
{
return(Content(HttpStatusCode.NotFound, "Student not found."));
}
return(Ok(student));
}
public ActionResult DataAnnotation(Student2 model)
{
//数据注解方式
if (ModelState.IsValid)
{
ViewBag.name = model.name;
ViewBag.email = model.email;
}
return(View());
}
public override string ToString()
{
string result = Student1.ToString();
if (Student2 != null)
{
result += ", " + Student2.ToString();
}
return(result);
}
/// <summary>
/// 删除测试
/// </summary>
/// <param name="p"></param>
/// <param name="db"></param>
private void Delete(Student2 p, SqlSugarClient db)
{
db.Delete <Student>(it => it.id == 1);
db.Delete <Student>(new Student()
{
id = 2
});
db.Delete <Student, int>(3, 4);
db.Delete <Student, int>(it => it.id, 5, 6);
var list = db.Queryable <Student>().ToList();
}
public IHttpActionResult GetStudent2(int id)
{
Student2 student2 = db.Student2.Find(id);
if (student2 == null)
{
return(NotFound());
}
return(Ok(student2));
}
private void button1_Click(object sender, EventArgs e)
{
if (listBox1.SelectedItem != null)
{
string student = listBox1.SelectedItem.ToString();
Student2 stu = DDD.getStudentObject(student);
Form11 form11 = new Form11(ref DDD, student);
string s = stu.firstName + " " + stu.middleName + " " + stu.lastName;
form11.ChangeLabelName(s);
form11.ShowDialog();
}
}
public IHttpActionResult PostStudent2(Student2 student2)
{
if (!ModelState.IsValid)
{
return(BadRequest(ModelState));
}
db.Student2.Add(student2);
db.SaveChanges();
return(CreatedAtRoute("DefaultApi", new { id = student2.IdStudent }, student2));
}
public static void Main()
{
// This Student uses get/set methods
Student s = new Student();
s.SetName("Fred");
Console.WriteLine("Name is " + s.GetName());
// This Student uses properties
Student2 s2 = new Student2();
s2.Name = "Maria";
Console.WriteLine("Name is " + s2.Name);
}
public IHttpActionResult DeleteStudent2(int id)
{
Student2 student2 = db.Student2.Find(id);
if (student2 == null)
{
return(NotFound());
}
db.Student2.Remove(student2);
db.SaveChanges();
return(Ok(student2));
}
public void Init()
{
Student2 p = new Student2()
{
id = 2, name = "张表", isOk = true
};
Console.WriteLine("启动Test.Init");
using (var db = SugarDao.GetInstance())
{
//拉姆达测试
Exp(p, db);
}
}
public void Init()
{
OracleConfig.SequenceMapping = new List <SequenceModel>()
{
new SequenceModel()
{
ColumnName = "ID", TableName = "STUDENT", Value = "SEQ"
},
new SequenceModel()
{
ColumnName = "ID", TableName = "AREA", Value = "SEQ2"
},
new SequenceModel()
{
ColumnName = "ID", TableName = "SCHOOL", Value = "SEQ3"
},
new SequenceModel()
{
ColumnName = "ID", TableName = "SUBJECT", Value = "SEQ4"
}
};
Student2 p = new Student2()
{
id = 2, name = "张表", isOk = true
};
Console.WriteLine("启动Test.Init");
using (var db = SugarDao.GetInstance())
{
//初始化数据
InitData(db);
//查询测试
Select(p, db);
//拉姆达测试
Exp(p, db);
//新容器转换测试
SelectNew(p, db);
//更新测试
Update(p, db);
//删除测试
//Delete(p,db);
}
}
static void Main(string[] args)
{
Controller controller = new Controller();
Menu menu = new Menu();
MainStudent student1 = new Student1().get();
MainStudent student2 = new Student2().get();
students.AddRange(new List <MainStudent>()
{
student2, student1
});
main : menu.Main();
int ordger;
try
{
ordger = int.Parse(Console.ReadLine());
switch (ordger)
{
case 1:
Console.Clear();
controller.ShowList(students);
break;
case 2:
Console.Clear();
controller.Show(students);
break;
case 3:
Console.Clear();
controller.Average(students);
break;
}
Console.ReadKey();
goto main;
}
catch
{
Console.WriteLine("\n!!!please enter number!!!");
goto main;
}
}
static void classexample()
{
Student2 firstStudent = new Student2("John", "Smith", "six");
Student2.StudentCount++;
Student2 secondStudent = new Student2("Tom", "Thumb", "two");
Student2.StudentCount++;
Console.WriteLine(firstStudent.firstName);
Console.WriteLine(secondStudent.firstName);
Console.WriteLine(Student2.StudentCount);
firstStudent.FirstName = "Hello";
secondStudent.FirstName = "Challo";
firstStudent.displayName();
secondStudent.displayName();
}
public IHttpActionResult PutStudent2(int id, Student2 student2)
{
if (!ModelState.IsValid)
{
return(BadRequest(ModelState));
}
if (id != student2.IdStudent)
{
return(BadRequest());
}
Student2 originalStudent = db.Student2.Find(id);
if (originalStudent != null)
{
originalStudent.Career = student2.Career;
originalStudent.File = student2.File;
originalStudent.FirstName = student2.FirstName;
originalStudent.LastName = student2.LastName;
originalStudent.IdNumber = student2.IdNumber;
originalStudent.StartYear = student2.StartYear;
}
try
{
db.SaveChanges();
}
catch (DbUpdateConcurrencyException)
{
if (!Student2Exists(id))
{
return(NotFound());
}
else
{
throw;
}
}
return(StatusCode(HttpStatusCode.NoContent));
}
/*
* 90分以上是A
* 80分以上是B
* 70分以上是C
* 60分以上是D
* 其餘是E
*/
static void Main(string[] args)
{
Student a = new Student();
a.Name = "靜香";
a.score = 83;
Student b = new Student();
b.Name = "出木杉";
b.score = 90;
Student c = new Student();
c.Name = "胖虎";
c.score = 68;
Student d = new Student();
d.Name = "葉大雄";
d.score = 17;
getGrade(a);
getGrade(b);
getGrade(c);
getGrade(d);
ChangeName(a);
Console.WriteLine($"a 的名字現在叫 {a.Name}");
ChangeName(b.Name);
Console.WriteLine($"b 的名字現在叫 {b.Name}");
ModifyScore(c);
Console.WriteLine($"c 的成績現在是 {c.score}");
ModifyScore(d.Name, d.score);
Console.WriteLine($"d 的成績現在是 {d.score}");
Student2 e = new Student2("小夫", 75);
Console.WriteLine($"{e.Name} 的分數是 {e.Score} ，成績為 {e.Grade}");
Console.WriteLine($"{e.Name} 如果加5分，分數是 {e.Score += 5}，成績為 {e.Grade}");
}
/// <summary>
/// 拉姆达测试
/// </summary>
/// <param name="p"></param>
/// <param name="db"></param>
private void Exp(Student2 p, SqlSugarClient db)
{
//解析拉姆达各种情况组合
//基本
var t1 = db.Queryable <Student>().Where(it => it.id == 1).ToList();
var t2 = db.Queryable <Student>().Where(it => it.id == p.id).ToList();
var t3 = db.Queryable <Student>().Where(it => it.id == _p.id).ToList();
var t4 = db.Queryable <Student>().Where(it => it.id == Getp().id).ToList();
var t5 = db.Queryable <Student>().Where(it => it.id == MyCost.p.id).ToList();
//BOOL
var t11 = db.Queryable <Student2>("Student").Where(it => it.isOk).ToList();
var t21 = db.Queryable <Student2>("Student").Where(it => it.isOk == MyCost.p.isOk).ToList();
var t31 = db.Queryable <Student2>("Student").Where(it => !it.isOk).ToList();
var t41 = db.Queryable <Student2>("Student").Where(it => it.isOk == true).ToList();
var t51 = db.Queryable <Student2>("Student").Where(it => it.isOk == false).ToList();
var t61 = db.Queryable <Student2>("Student").Where(it => it.isOk == _p.isOk).ToList();
var t71 = db.Queryable <Student2>("Student").Where(it => !it.isOk && !p.isOk == it.isOk).ToList();
var t91 = db.Queryable <Student2>("Student").Where(it => _p.isOk == false).ToList();
var t81 = db.Queryable <Student>().Where(it => it.isOk == false).ToList();
var t111 = db.Queryable <Student2>("Student").Where(it => it.isOk && false).ToList();
//length
var c1 = db.Queryable <Student>().Where(c => c.name.Length > 4).ToList();
var c2 = db.Queryable <Student>().Where(c => c.name.Length > _p.name.Length).ToList();
var c3 = db.Queryable <Student>().Where(c => c.name.Length > "aa".Length).ToList();
var c4 = db.Queryable <Student>().Where(c => c.name.Length > Getp().id).ToList();
//Equals
var a1 = db.Queryable <Student>().Where(c => c.name.Equals(null)).ToList();
var x = new InsertTest()
{
};
var x1 = db.Queryable <Student>().Where(c => c.name.Equals(x.int1)).ToList();
var a2 = db.Queryable <Student>().Where(c => c.name.Equals(p.name)).ToList();
var a4 = db.Queryable <Student>().Where(c => c.name.Equals(Getp().name)).ToList();
//Contains
var s = db.Queryable <Student>().Where(c => c.name.Contains(null)).ToList();
var s0 = new InsertTest()
{
};
var s1 = db.Queryable <Student>().Where(c => c.name.Contains(x.v1)).ToList();
var s3 = db.Queryable <Student>().Where(c => c.name.Contains(p.name)).ToList();
var s4 = db.Queryable <Student>().Where(c => c.name.Contains(Getp().name)).ToList();
var s5 = db.Queryable <Student>().Where(c => c.name.StartsWith(Getp().name)).ToList();
var s6 = db.Queryable <Student>().Where(c => c.name.EndsWith(Getp().name)).ToList();
//异常处理测试,防止程序中出现未知错误
try
{
var e6 = db.Queryable <Student>().Where(c => Getp().name.StartsWith(c.name)).ToList();
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
try
{
var e6 = db.Queryable <Student>().Where(c => Getp().name.Equals(c.name)).ToList();
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
try
{
var e6 = db.Queryable <Student>().Where(c => c.name.First() != null).ToList();
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
//组合测试
var z = db.Queryable <Student>().Where(c => (c.name.Equals(Getp().name) || c.name == p.name) && true && c.id > 1).ToList();
var z23 = db.Queryable <Student>().Where(c => !string.IsNullOrEmpty(c.name) || (c.id == 1 || c.name.Contains(p.name))).ToList();
var z2 = db.Queryable <Student>().Where(c => !string.IsNullOrEmpty(c.name) || !string.IsNullOrEmpty(c.name)).ToList();
}
/// <summary>
/// 测试select new
/// </summary>
/// <param name="p"></param>
/// <param name="db"></param>
private void SelectNew(Student2 p, SqlSugarClient db)
{
//测试用例
var queryable = db.Queryable <Student>().Where(c => c.id < 10)
.Select <V_Student>(c => new V_Student {
id = c.id, name = c.name, AreaName = "默认地区", SchoolName = "默认学校", SubjectName = "NET"
});
var list = queryable.ToList();
//多表操作将Student转换成V_Student
var queryable2 = db.Queryable <Student>()
.JoinTable <School>((s1, s2) => s1.sch_id == s2.id)
.Where <School>((s1, s2) => s2.id < 10)
.Select <School, V_Student>((s1, s2) => new V_Student()
{
id = s1.id, name = s1.name, AreaName = "默认地区", SchoolName = s2.name, SubjectName = "NET"
}); //select new 目前只支持这种写法
var list2 = queryable2.ToList();
//select字符串 转换成V_Student
var list3 = db.Queryable <Student>()
.JoinTable <School>((s1, s2) => s1.sch_id == s2.id)
.Where(s1 => s1.id <= 3)
.Select <V_Student>("s1.*,s2.name SchoolName")
.ToList();
//新容器转换函数的支持 只支持ObjToXXX和Convert.ToXXX
var f1 = db.Queryable <InsertTest>().Select <Student>(it => new Student()
{
name = it.d1.ObjToString(),
id = it.int1.ObjToInt() // 支持ObjToXXX 所有函数
}).ToList();
var f2 = db.Queryable <InsertTest>().Select <Student>(it => new Student()
{
name = Convert.ToString(it.d1),//支持Convet.ToXX所有函数
id = it.int1.ObjToInt(),
sex = Convert.ToString(it.d1),
}).ToList();
var f3 = db.Queryable <InsertTest>()
.JoinTable <InsertTest>((i1, i2) => i1.id == i2.id)
.Select <InsertTest, Student>((i1, i2) => new Student()
{
name = Convert.ToString(i1.d1), //多表查询例子
id = 1,
sex = Convert.ToString(i2.d1),
}).ToList();
//Select 外部参数用法
var f4 = db.Queryable <InsertTest>().Where("1=1", new { id = 100 }).Select <Student>(it => new Student()
{
id = "@id".ObjToInt(), //取的是 100 的值
name = "张三", //内部参数可以直接写
sex = it.txt,
sch_id = it.id
}).ToList();
var f6 = db.Queryable <InsertTest>()
.JoinTable <InsertTest>((i1, i2) => i1.id == i2.id)
.Where("1=1", new { id = 100, name = "张三", isOk = true }) //外部传参给@id
.Select <InsertTest, Student>((i1, i2) => new Student()
{
name = "@name".ObjToString(), //多表查询例子
id = "@id".ObjToInt(),
sex = i2.txt,
sch_id = 1,
isOk = "@isOk".ObjToBool()
}).ToList();
try
{
//测试用例
db.Queryable <Student>().Where(c => c.id < 10)
.Select <V_Student>(c => new V_Student {
id = c.id, name = _p.name, AreaName = "默认地区", SchoolName = "默认学校", SubjectName = "NET"
}).ToList();
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
try
{
//测试用例
db.Queryable <Student>().Where(c => c.id < 10)
.Select <V_Student>(c => new V_Student {
id = c.id, name = p.name, AreaName = "默认地区", SchoolName = "默认学校", SubjectName = "NET"
}).ToList();
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
try
{
//测试用例
db.Queryable <Student>().Where(c => c.id < 10)
.Select <V_Student>(c => new V_Student {
id = c.id, name = Getp().name, AreaName = "默认地区", SchoolName = "默认学校", SubjectName = "NET"
}).ToList();
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
try
{
//测试用例
db.Queryable <Student>().Where(c => c.id < 10)
.Select <V_Student>(c => new V_Student {
id = c.id, name = Getp2(), AreaName = "默认地区", SchoolName = "默认学校", SubjectName = "NET"
}).ToList();
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
try
{
//测试用例
db.Queryable <InsertTest>()
.JoinTable <InsertTest>((i1, i2) => i1.id == i2.id)
.Select <InsertTest, Student>((i1, i2) => new Student()
{
name = Getp2(), //多表查询例子
id = i1.int1.ObjToInt(),
sex = Convert.ToString(i2.d1),
}).ToList();
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
try
{
//测试用例
db.Queryable <InsertTest>()
.JoinTable <InsertTest>((i1, i2) => i1.id == i2.id)
.Select <InsertTest, Student>((i1, i2) => new Student()
{
name = Getp().name, //多表查询例子
id = i1.int1.ObjToInt(),
sex = Convert.ToString(i2.d1),
}).ToList();
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
try
{
//测试用例
db.Queryable <InsertTest>()
.JoinTable <InsertTest>((i1, i2) => i1.id == i2.id)
.Select <InsertTest, Student>((i1, i2) => new Student()
{
name = Getp().name, //多表查询例子
id = i1.int1.ObjToInt(),
sex = Convert.ToString(i2.d1),
}).ToList();
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
try
{
//测试用例
db.Queryable <InsertTest>()
.JoinTable <InsertTest>((i1, i2) => i1.id == i2.id)
.Select <InsertTest, Student>((i1, i2) => new Student()
{
name = Getp().name, //多表查询例子
id = i1.int1.ObjToInt() + 1,
sex = Convert.ToString(i2.d1),
}).ToList();
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
try
{
//测试用例
db.Queryable <InsertTest>()
.JoinTable <InsertTest>((i1, i2) => i1.id == i2.id)
.Select <InsertTest, Student>((i1, i2) => new Student()
{
name = p.name, //多表查询例子
sex = Convert.ToString(i2.d1),
}).ToList();
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
}
private void button1_Click(object sender, EventArgs e)
{
//Form2 form2 = new Form2(students, admin, faculty, courses, null);
bool flag = false;
foreach (DataRow row in DDD.FacultyDB.Rows)
{
if (row.Field <string>(0) == textBox1.Text.ToLower() && row.Field <string>(1) == textBox2.Text)
{
Faculty2 fac = DDD.getFacultyObject(textBox1.Text.ToLower());
Form5 form5 = new Form5(ref DDD, fac.user);
//List<Course> studentsCourses = element.getRegisteredCourses();
//courseBox = new List<string>();
//if (studentsCourses == null)
//{
// courseBox.Add("You are not registered for any courses yet!");
//}
//else
//{
// courseBox.Clear();
// foreach (Course c in studentsCourses)
// {
// courseBox.Add(c.ToString());
// }
//}
string s = "Welcome " + fac.firstName + " " + fac.middleName + " " + fac.lastName;
form5.ChangeLabelName(s);
form5.ShowDialog();
flag = true;
form5.Refresh();
break;
//Faculty2 faculty = DDD.getFacultyObject(textBox1.Text.ToLower());
//Form5 form5 = new Form5(ref DDD, faculty.user);
//string s = "Welcome " + faculty.firstName + " " + faculty.middleName + " " + faculty.lastName;
//form5.ChangeLabelName(s);
//form5.ShowDialog();
//flag = true;
//form5.Refresh();
//break;
}
}
foreach (DataRow row in DDD.AdminDB.Rows)
{
if (row.Field <string>(0) == textBox1.Text.ToLower() && row.Field <string>(1) == textBox2.Text)
{
Admin2 adm = DDD.getAdminObject(textBox1.Text.ToLower());
Form9 form9 = new Form9(ref DDD, adm.user);
//Admin2 admin = DDD.getAdminObject(textBox1.Text.ToLower());
//Form2 form2 = new Form2(DDD, admin);
//string s = "Welcome " + admin.firstName + " " + admin.middleName + " " + admin.lastName;
//form2.ChangeLabelName(s);
//form2.ShowDialog();
//flag = true;
//break;
string s = "Welcome " + adm.firstName + " " + adm.middleName + " " + adm.lastName;
form9.ChangeLabelName(s);
form9.ShowDialog();
flag = true;
form9.Refresh();
break;
}
}
foreach (DataRow row in DDD.StudentDB.Rows)
{
if (row.Field <string>(0) == textBox1.Text.ToLower() && row.Field <string>(1) == textBox2.Text)
{
Student2 student = DDD.getStudentObject(textBox1.Text.ToLower());
Form2 form2 = new Form2(ref DDD, student.user);
//List<Course> studentsCourses = element.getRegisteredCourses();
//courseBox = new List<string>();
//if (studentsCourses == null)
//{
// courseBox.Add("You are not registered for any courses yet!");
//}
//else
//{
// courseBox.Clear();
// foreach (Course c in studentsCourses)
// {
// courseBox.Add(c.ToString());
// }
//}
string s = "Welcome " + student.firstName + " " + student.middleName + " " + student.lastName;
form2.ChangeLabelName(s);
form2.ShowDialog();
flag = true;
form2.Refresh();
break;
}
}
if (flag == false)
{
MessageBox.Show("The Username or Password is Incorrect", "Error");
textBox2.Text = "";
}
else
{
textBox1.Text = "";
textBox2.Text = "";
}
}
static void main(string[] args)
{
/*
* Inheritance -
* allows us to define a class based on another class. This makes creating and maintaining an application easy.
* The class whose properties are inherited by another class is called the Base class. The class which inherits the properties is called the Derived class.
* for example, Base class Animal can be used to derive Cat and Dog classes.
* The derived class inherits all the features from the base class and can have its own additional features
* example line(12)
*/
Dog d = new Dog();
Console.WriteLine(d.Legs); //output is 4
d.Bark(); //output Woof
//A base clase can have multiple derived classes.
//for example, a Cat class can inherit from Animal
//Inheritance allows the derived class to reuse the code in the base class without having to rewrite it. Also the derive class can be customized by
//adding more members. In this manner, the derived class extends the functionality of the base class.
/*A derived class inherits all the members of the base class, including its methods
* example line(30)
*
*/
Student s = new Student();
s.Speak(); // output Hi there
//C# does not support multiple inheritance, so we cannot inherit from multiple classes, however, we can use interfaces to implement multiple inheritance
/*
* Protected -
* This access modifier is very similar to private access modifier with one difference.
* A Protected access modifier can be accessed in the derived classes. So a protected member is accessible only from derived classes
* example line(43)
*/
Student2 s2 = new Student2("Iykeman");
s2.Speak();
/*Sealed -
* A class can prevent other classes from inheritig it, or any of its members by using the sealed modifier. example
* sealed class Animal {
* //some code
* }
* class Dog : Animal { } // Error
* The sealed keyword provides a level of protection to your class so that other classes cannot inherit from it
*/
/*Derived Class Constructor and Destructor
* Contructors are called when objects of a class are created. With inheritance, the base class constructor and destructor are not inherited, so we should
* define constructors for the derived classes.
* However, he base class constructor and destructor are being invoked automatically when an object of the derived class is created or derleted
* consider example line(61)
* Note that the base class constructor is called first and the derived class constructor is called next. When the object is destroyed, the derived class
* destructor is invoked and then the base class destructor is invoked.
* we can think of this as the following: the derived class needs its base class in order to work which is why the base class constructor is called first
*/
Cow c = new Cow();
/* Polymorphism -
* this word means having many forms, it occurs when there is a hierarchy of classes and they are related through inheritance from a common base class.
* Polymorphism means that a call to a member method will cause a different implementation to be executed depending on the type of object that invokes the method.
* This simplt means that a single method can have a number of different implementations.
* -Consider having a program that alllows users to draw different shapes.Each shape is drawn differently and you do not know which shape the user will choose,
* Here, polymorphism can be leveraged to invoke the appropriate Draw method of any derived class. Such methods must be declared using the virtual keyword in the base class
* example below and line(85)
* class shape {
* public virtual void Draw() {
* Console.WriteLine("Base Draw");
* }
* }
* The virtual keyword allows methods to be overridden in derived classes.
* Virtual methods enable us to work with groups of related objects in a uniform way.
*
* we can derive different shape classes that define their own Draw methods using the override keyword. example line (93).
* The virtual Draw method in the Shape base class can be overridden in the derived classes. In this case, Circle and Rectangle have their own Draw methods.
* we can create separate Shape objects for each derived type and then call their Draw methods
*/
Shape cc = new Circle();
cc.Draw(); // output "Circle Draw"
Shape rt = new Rectangle();
rt.Draw(); //output "Rectangle Draw"
/*Polymorphism is useful in many cases, For example, we could create a game where we would have different player types with each player
* having a separate behaviour for the Attack method.
* In this case, Attack would be a virtual method of the base class Player and each derived class would override it.
*/
/*Abstract Classes -
* In situation where it is not meaningful for the virtual method(polymorphism) to have a separate definition in base class,
* we defined this method with the abstract keyword and specify that the derived classes must define their method on their own.
* we cannot create objects of a class containing an abstract method, which is why the class itself should be abstract
* lets use abstract method in the shape class as in polymorphism case, example line (113)
* The draw method on line 133 is abstract and thus has no body, we do not even need a curly brackets, just end the statement with a semicolon.
* The Shape class itself must be declared abstract because it contains an abstract method. Abstract method declarations are only permitted in abstract classess
* Members marked as abstract or included in an abstract class must be implemented by classes that derive from the abstract class.
* An abstract class can have multiple abstract members
* Ab abstract class is intended to be a base class of other classess. It acts like a template for its derived classes.
* we can now define other classes and define their own Draw() method. example line(117)
*/
Shape2 cc2 = new Circle2();
cc.Draw(); // output "Circle Draw"
Shape2 rt2 = new Rectangle2();
rt.Draw(); //output "Rectangle Draw"
/*Abstract class have the following features
* An abstract class cannot be instantiated
* An abstract class may contain abstract methods and accessors
* A non-abstract class derived from an abstract class must include actual implementations of all inherited abstract methods and accessors
* Note that it is not possible to modify an abstract class with the sealed modifier because the two modifiers have opposite meanings.
* The sealed modifier prevents a class from being inherited and the abstract modifier requires a class to be inherited
*/
/* Interfaces -
* An interface is a completely abstract class, which contains only abstract members. It is declared using the interface keyword,
* Example -
* public interface IShape
* {
* void Draw();
* }
* All members of the interface are by default abstract, so no need to use the abstract keyword.
* Also all members of an interface are always public, an no access modifiers can be applied to them.
* It is common to use the capital letter I as the starting letter for an interface name.
* Interfaces can contain properties, methods, etc but cannot contain fields (variables).
*
* When a class implements an interface, it must also implement, or define, all of its methods.
* The term implementing an interface is used(opposed to the term "inheriting from") to describe the process of creating a class based on an
* interface. The interface simply describes what a class should do. The class implementing the interface must define how to accomplish the behaviours.
* The syntax to implement an interface is the same as that to derive a class.
* example line (134)
*/
IShape ca = new CircleA();
ca.Draw(); //Output "Circle Draw"
/*Note that the override keyword is not needed when you implement an interface
* Why use interfaces rather than abstract classes?
* A class can inherit from just one base class, but it can implement multiple interfaces!
* Therefore, by using interfaces we can include behaviour from multiple sources in a class.
* To implement multiple interfaces, use a comma separated list of interfaces when creating the class: Class A : IShape, IAnimal, etc
*/
/*
* Nested Classes
* C# supports nested classes, a nested class is a class that is a member of another class. example below & line (148)
* class Car {
* string name;
* public Car(string nm) {
* name = nm;
* Motor m = new Motor();
* }
* public class Motor {
* // some code
* }
* }
*
* The Motor class is nested in the Car class and can be used similar to other members of the class.
* A nested class acts as a member of the class, so it can have the same access modifiers as other members(public, private, protected).
*
* Just as in real life, objects can contain other objects. For example, a car, which has its own attributes(color, brand, etc) contains
* a motor, which as a separate object, has its own attributes(volume, horsepower, etc).
* Here, the Car class can have a nested Motor class as one of its members
*/
/*Namespaces
* when we create a blank project, it has the following structure:
*
* using System;
* using System.Collections.Generic;
* using System.Linq;
* using.System.Text;
* using System.Threading.Tasks;
*
* namespace SoloLearn {
* class Program {
* static void Main(string[] args) {
* }
* }
* }
*
* Note that our whole program is inside a namespace. So, what are namespaces?
* Namespaces declare a scope that contains a set of related objects. You can use a namespace to organize code elements.
* You can define your own namespaces and use them in your program. The using keyword states that the rpogram is using a given namespace.
* for example, we are using the System namespace in our programs, which is where the class Console is defined. Without the using
* statement, we would have to specify the namespace whereever it is used like below
* System.Console.WriteLine("Hello world");
*
* The .NET framework uses namespaces to organize its many classes. System is one example of a .NET framework namespaces. Declaring your
* own namespaces can help you group your class and method names in larger programming projects
*
*/
}
