Use the LINQ method to change the search and delete

  func<string, string> fc = Delegate (string a)//{//A + = "Hello";            return A;            //}; MessageBox.Show (FC ("5").            ToString ());            Dataclasses1datacontext context = new Dataclasses1datacontext (); list<bread> list = Context.bread.Where (r = Convert.todecimal (R.breadprice.tostring ()) < 15).            ToList ();            var list2 = from quary in Context.bread where Convert.todecimal (quary.breadprice.ToString ()) < select Quary;            Datagridview1.autogeneratecolumns = true; Datagridview1.datasource = list2;/////////////////////////////////////////////////////////////////////////////// public class Studentda {private Dataclasses1datacontext _context        ;        Public Studentda () {_context = new dataclasses1datacontext (); }//Add data public void Insert (Student data) {_context.            Student.insertonsubmit (data); _context.        SubmitChanges (); }//Modify data public void update (Student data) {Student sdata =_context. Student.single (r = R.sno = = data.            Sno); if (sdata! = null) {sdata. Sno = data.                Sno; Sdata. Sname = data.                Sname; Sdata. Ssex = data.                Ssex; Sdata. Sbirthday = data.                Sbirthday; _context.            SubmitChanges (); }}//delete data public void Delete (Student data) {Student sdata = _context. Student.single (R=>r.sno==data.            Sno); _context.            Student.deleteonsubmit (sdata); _context.        SubmitChanges (); ////////Delete public void Delete (String sno) {Student data = _context According to the student number.            Student.single (r = R.sno = = Sno); if (data! = NULL) {_context.                Student.deleteonsubmit (data); _context. SubmitchaNges (); }}///////////queries all student data public list<student> Select () {return _context. Student.tolist (). Count>0? _context.        Student.tolist (): null; }///////////////Queries public Student Select (String sno) {return _context according to the student number. Student.where (r = R.sno = = Sno).        First (); }/////////////Query Public list<student> selectbyname (string sname) {List <student&gt by student name ; List= _context. Student.where (r = r.sname.contains (Sname)).           ToList (); Return list. Count>0?        List:null; }    }}////////////////////////////////////////////////////////////////////////////////////////////////////////////               Add data to the database Student the new Student {sno=textbox1.text, Sname=textbox2.text, Ssex=radiobutton1.checked? "                            Male ":" female ", Sbirthday=datetimepicker1.value, Class=textbox3.text,             };            New Studentda (). Insert (data),/////////////query data from database using LINQ method private void Form3_load (object sender, EventArgs e) {            list<student> list = new Studentda (). Select ();                if (list = null) {Datagridview1.autogeneratecolumns = true;            Datagridview1.datasource = list;            }//////////uses LINQ methods to query private void Button1_Click (object sender, EventArgs e) from the database by name {            list<student> list = new Studentda (). Selectbyname (TextBox1.Text);                if (list = null) {Datagridview1.autogeneratecolumns = true;            Datagridview1.datasource = list; }/////////Delete data from database using LINQ method private void Button2_Click (object sender, EventArgs e) {if            (DataGridView1.SelectedRows.Count > 0) {Student data = (Student) datagridview1.selectedrows[0].                Databounditem; NeW STUDENTDA (). Delete (data);            } Datagridview1.autogeneratecolumns = true;        Datagridview1.datasource = new Studentda (). Select (); private void Button3_Click (object sender, EventArgs e) {if (DataGridView1.SelectedRows.Count & Gt 0) {Form4 f = new FORM4 ((Student) datagridview1.selectedrows[0].                Databounditem);            F.show (); }} private Student sdata;////The selected information to the appropriate local constructor public Form4 (Student data) {initializecom            Ponent ();        sdata = data; The private void Form4_load (object sender, EventArgs e) {TextBox1.Text = Sdata.            Sno; TextBox2.Text = sdata.            Sname; TextBox3.Text = sdata.            Class; if (sdata.            Ssex = = "Male") {radiobutton1.checked = true;            } else {radiobutton2.checked = true; } DateTimePicker1.Value = DateTime.Parse (sdata.        Sbirthday.tostring ()); }////////////////////////////////////////////////////////////////////////The returned information is modified and returned to the database private void button1_            Click (object sender, EventArgs e) {Student sdata = new Student (); Sdata.            Sno = TextBox1.Text; Sdata.            Sname = TextBox2.Text; Sdata.            Class = TextBox3.Text; Sdata. Ssex = radiobutton1.checked?            "Male": "Female"; Sdata.            Sbirthday = Datetimepicker1.value;            New STUDENTDA (). Update (sdata); This.        Close (); }

Use the LINQ method to change the search and delete