unit4.pas

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unit Unit4;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, Buttons, Grids, DBGrids, DB;

type
  TForm4 = class(TForm)
    DataSource1: TDataSource;
    DBGrid1: TDBGrid;
    BitBtn1: TBitBtn;
    SpeedButton1: TSpeedButton;
    SpeedButton2: TSpeedButton;
    Button1: TButton;
    SpeedButton3: TSpeedButton;
    GroupBox1: TGroupBox;
    procedure BitBtn1Click(Sender: TObject);
    procedure SpeedButton1Click(Sender: TObject);
    procedure SpeedButton2Click(Sender: TObject);
    procedure Button1Click(Sender: TObject);
    procedure SpeedButton3Click(Sender: TObject);
  private
    { Private declarations }

  public
    { Public declarations }
  end;

var
  Form4: TForm4;

implementation

uses Unit2, ADODB, Unit5;

{$R *.dfm}

procedure TForm4.BitBtn1Click(Sender: TObject);
begin
  with DM.qrySQLStus do
  begin
    if Active then Active := False;
    SQL.Text := 'Select * From Students';
    Open;
    DM.StudentsInfoDisplayHdl;
  end;
end;

procedure TForm4.SpeedButton1Click(Sender: TObject);
var
  iUserChoice : Integer;
  strCmd : String;
  bkMark : TBookmark; //书签的使用
begin
  if DM.qrySQLStus.Active then
  begin
    iUserChoice := Application.MessageBox('','',MB_YESNO+MB_ICONQUESTION);
    if iUserChoice = mrYes then
    begin
      bkMark := DM.qrySQLStus.GetBookmark; //保存书签
      with DM.qryTmp do
      begin
        if Active then Active := False;
        StrCmd := 'Delete From Students Where '
                + DM.qrySQLStus.Fields[0].FieldName
                + '='
                + QuotedStr(DM.qrySQLStus.Fields[0].AsString);
        SQL.Text := strCmd;
        ExecSQL;//当前使用的是非查询语句，故不能使用open
        DM.qrySQLStus.Requery;//更新显示在用户面前的数据
        DM.qrySQLStus.GotoBookmark(bkMark);//移动到书签
      end;
    end;
  end;
end;

procedure TForm4.SpeedButton2Click(Sender: TObject);
var
  strValStuName, strValStuClass : String;
  strCmd : String;
  bkMark : TBookmark;
begin
  if not DM.qrySQLStus.Active then
  begin
    Application.MessageBox('','',MB_OK);
    Exit;
  end;
  strValStuName := Trim(InputBox('修改','学生姓名',DM.qrySQLStus.Fields[1].AsString));
  if strValStuName='' then
  begin
    Application.MessageBox('输入数据非法，不能修改','',MB_OK);
    Exit;
  end;
  strValStuClass := Trim(InputBox('修改','学生班级',DM.qrySQLStus.Fields[2].AsString));
  if strValStuClass='' then
  begin
    Application.MessageBox('输入数据非法，不能修改','',MB_OK);
    Exit;
  end;
  with DM.qryTmp do
  begin
    bkMark := DM.qrySQLStus.GetBookmark;
    if Active then Active := False;
    strCmd := 'Update Students Set StuName=' + QuotedStr(strValStuName) + ','
            + 'StuClass=' + QuotedStr(strValStuClass) + ' '
            + 'Where StuNO=' + QuotedStr(DM.qrySQLStus.Fields[0].AsString);
    SQL.Text := strCmd;
    ExecSQL;
    DM.qrySQLStus.Requery;
    DM.qrySQLStus.GotoBookmark(bkMark);
  end;
end;

procedure TForm4.Button1Click(Sender: TObject);
begin
  if DM.qrySQLStus.Active then
    DM.qrySQLStus.Close;
end;

procedure TForm4.SpeedButton3Click(Sender: TObject);
var
  bkMark : TBookmark;
begin
  Form5 := TForm5.Create(Self);
  if Form5.ShowModal = mrOK then
  begin
    bkMark := DM.qrySQLStus.GetBookmark;
    DM.qrySQLStus.Requery;
    DM.qrySQLStus.GotoBookmark(bkMark);
  end;
  Form5.Free;
end;

end.