(LINQ) (5) Examples of the LINQ Tutorial: query by adding, deleting, modifying, and deleting a single table operation

Add operation Private Void Toolstripbtnadd_click ( Object Sender, eventargs E)
{
// Create a new class and assign values to the attributes
Student mystudent = New Student ();
Mystudent. studentname = " Meetweb " ;
Mystudent. Sex = " Man " ;
Mystudent. Old = 17 ;
Dataclasses1datacontext DB = New Dataclasses1datacontext (sqlconstr );
DB. Student. insertonsubmit (mystudent );
DB. submitchanges ();
Dataload ();
// This. Maid ();
}

Delete operation

Private Void Toolstripbtndel_click ( Object Sender, eventargs E)
{
// Delete action
Dataclasses1datacontext DB = New Dataclasses1datacontext (sqlconstr );
// Need to delete the ID is 6
Student mystudent = dB. gettable <student> (). First <student> (P => P. ID = 4 );
DB. Student. deleteonsubmit (mystudent );
}

Update operation

Private Void Toolstripbtnsave_click ( Object Sender, eventargs E)
{
// Modify action
Dataclasses1datacontext DB = New Dataclasses1datacontext (sqlconstr );
// Need to update the ID is 6
Student mystudent = dB. gettable <student> (). First <student> (P => P. ID = 5 );
Mystudent. Old = 18 ;
Mystudent. Sex = " Woman " ;
DB. submitchanges ();
}

Multi-condition Query

Private List <student> Search ( String ID, String Studentname)
{
Dataclasses1datacontext DB = New Dataclasses1datacontext (sqlconstr );
List <student> mystudent = dB. gettable <student> (). First <student> (P => P. ID = 4 & P. studentname = studentname). tolist ();

Return mystudent;
}