unit8.pas

本系统为学生管理系统,可实现选课和退选

unit Unit8;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, DBTables, DB, StdCtrls, Mask, DBCtrls, Grids, DBGrids, ExtDlgs;

type
  TForm8 = class(TForm)
    Label3: TLabel;
    Label6: TLabel;
    Label7: TLabel;
    Label12: TLabel;
    Label13: TLabel;
    GroupBox1: TGroupBox;
    DBEdit1: TDBEdit;
    DBEdit2: TDBEdit;
    DBEdit3: TDBEdit;
    DBEdit4: TDBEdit;
    DBEdit5: TDBEdit;
    DBEdit6: TDBEdit;
    Label1: TLabel;
    Label15: TLabel;
    Label16: TLabel;
    Label17: TLabel;
    Label18: TLabel;
    Label19: TLabel;
    Label20: TLabel;
    GroupBox3: TGroupBox;
    Label11: TLabel;
    Button1: TButton;
    Button2: TButton;
    Edit5: TEdit;
    ComboBox1: TComboBox;
    Label14: TLabel;
    GroupBox4: TGroupBox;
    GroupBox5: TGroupBox;
    GroupBox6: TGroupBox;
    Edit1: TEdit;
    Label4: TLabel;
    Button3: TButton;
    DBGrid1: TDBGrid;
    Label23: TLabel;
    Table2: TTable;
    DataSource1: TDataSource;
    DataSource2: TDataSource;
    DataSource3: TDataSource;
    Table1: TTable;
    Query1: TQuery;
    DBGrid2: TDBGrid;
    Query2: TQuery;
    Button5: TButton;
    DBMemo1: TDBMemo;
    Label2: TLabel;
    Label21: TLabel;
    Edit3: TEdit;
    Edit6: TEdit;
 procedure updatetext();
    procedure Button3Click(Sender: TObject);
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);

    procedure Button5Click(Sender: TObject);
    


   
    procedure DBGrid2CellClick(Column: TColumn);

    procedure DBGrid1CellClick(Column: TColumn);

  private
    { Private declarations }
  public
    { Public declarations }
    temptext: string;
  end;

var
  Form8: TForm8;

implementation

{$R *.dfm}

procedure TForm8.updatetext();
begin
query1.close;
query1.sql.Clear;
query1.sql.Add('Select sum(course.ccredit) from xk,course where xk.cno=course.cno and xk.sno=:sno');
query1.ParamByName('sno').AsString:=edit1.Text;
query1.Open;
edit6.text:=query1.fields[0].asstring;
query1.SQL.Clear;
query1.SQL.Add('select count(cno) from xk where xk.sno=:sno');
query1.ParamByName('sno').AsString:=edit1.Text;
query1.open;
edit3.text:=query1.Fields[0].AsString;
query1.close;
end;
procedure TForm8.Button3Click(Sender: TObject);
begin
table1.close;
table1.Open;
table1.active:=true;
if   table1.Locate('sno',edit1.Text,[locaseinsensitive])=false then
begin
        table1.Active:=false;
        showmessage('无此学生,添加记录请进入数据维护');
        exit;
end
else
begin
query2.close;
query2.SQL.clear;
query2.SQL.Add('select * from xk where xk.sno=:sno');
query2.ParamByName('sno').AsString:=edit1.text;
query2.Open;

end;
updatetext();


end;

procedure TForm8.Button1Click(Sender: TObject);
var
k:integer;
begin
k:=1;
query1.Close;
query1.sql.clear;
query1.SQL.Add('select cno from course');
query1.Open;
while   not  query1.Eof  do
begin
        if edit5.text=query1.Fields[0].AsString then
                k:=0 ;
        query1.Next;

end;
if k=1 then
begin
        showmessage('输入该课程号不存在');
        exit;
end;
query1.close;
query1.close;
query1.SQL.clear;
query1.SQL.Add('select cno from xk where sno=:sno');
query1.ParamByName('sno').AsString:=edit1.Text;
query1.Open;
k:=1;
while   not  query1.Eof  do
begin
        if edit5.text=query1.Fields[0].AsString then
                k:=0 ;
        query1.Next;

end;
 query1.close;
if k=0 then
begin
        showmessage('该课程号已选修');
        exit;

end
else
begin
query2.sql.clear;
query2.SQL.Add('insert into  xk(sno,cno,grade,sjxq) values(:sn1,:cn1,-1,:sj)');
query2.ParamByName('sn1').AsString:=edit1.text;
query2.ParamByName('cn1').AsString:=edit5.text;
query2.ParamByName('sj').AsString:=combobox1.Text;
query2.ExecSQL;
updatetext();
end;
end;



procedure TForm8.Button5Click(Sender: TObject);
begin
button3.Click;
end;







{
procedure TPCheckForm.Button4Click(Sender: TObject);

begin
  table1.Edit;
  if openpicturedialog1.Execute then
    dbimage1.Picture.LoadFromFile(openpicturedialog1.FileName);
  table1.Post;  
end;

procedure TPCheckForm.Button6Click(Sender: TObject);
begin
  table1.Edit;
  dbimage1.Picture:=nil;
  table1.Post;
end;
    }
procedure TForm8.DBGrid2CellClick(Column: TColumn);
begin
try
       edit5.Text:=dbgrid2.Columns.Items[1].Field.asstring;
except
        showmessage('该生还未选修');
end;
end;




procedure TForm8.DBGrid1CellClick(Column: TColumn);
begin
try
          edit5.Text:=dbgrid1.Columns.Items[0].Field.asstring;
except
        showmessage('还未选择课程');
end;
end;

end.