friendsqryunit.pas

一个简单的数据库管理系统,是用delphi开发的.

unit FriendsQryUnit;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, ExtCtrls, Buttons;

type
  TFriendsQryForm = class(TForm)
    Panel1: TPanel;
    Bevel1: TBevel;
    ComboBox1: TComboBox;
    Label1: TLabel;
    ComboBox2: TComboBox;
    YesButton: TSpeedButton;
    CloseButton: TSpeedButton;
    Edit1: TEdit;
    CheckBox1: TCheckBox;
    procedure ComboBox1Change(Sender: TObject);
    procedure CloseButtonClick(Sender: TObject);
    procedure YesButtonClick(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  FriendsQryForm: TFriendsQryForm;

implementation
uses DataUnit,PublicUnit;
{$R *.dfm}

procedure TFriendsQryForm.ComboBox1Change(Sender: TObject);
begin
 if trim(ComboBox1.Text) = '' then Exit;
 Edit1.Text := '';
 ComboBox2.Text := '';
 CheckBox1.Checked := False;
 if trim(ComboBox1.Text)= '姓名' then
 begin
   ComboBox2.Visible := False;
   CheckBox1.Enabled := true;
   Edit1.Visible := True;
   Edit1.SetFocus;
 end else
 begin
  Edit1.Visible := False;
  CheckBox1.Enabled := False;
  ComboBox2.Visible := true;
  combobox2.Items.clear;
  ComboBox2.SetFocus;
  if Trim(ComboBox1.Text) = '性别' then
  begin
    ComboBox2.Items.Add('男');
    ComboBox2.Items.Add('女');
  end
  else if Trim(ComboBox1.Text) = '分类' then
  begin
    ComboBox2.Items.Add('家人');
    combobox2.Items.Add('亲戚');
    combobox2.Items.Add('朋友');
    ComboBox2.Items.Add('同事');
    combobox2.Items.Add('同学');
    ComboBox2.Items.Add('合作伙伴');
  end;
 end;
end;

procedure TFriendsQryForm.CloseButtonClick(Sender: TObject);
begin
  close;
end;

procedure TFriendsQryForm.YesButtonClick(Sender: TObject);
var
  SQLText,Fiel,Cond:string;
begin
  if Trim(ComboBox1.Text) = '' then
  begin
    ShowMessage('请选择查询条件。');
    ComboBox1.SetFocus;
  end;
  if trim(ComboBox1.Text) = '姓名' then
    Fiel := 'Name'
  else if trim(ComboBox1.Text) = '性别' then
    Fiel := 'Sex'
  else if trim(ComboBox1.Text) = '分类' then
    Fiel := 'Class';

  if Edit1.Visible then
    Cond := Trim(Edit1.Text)
  else
    Cond := Trim(ComboBox2.Text);
  if CheckBox1.Checked then
    SQLText := 'Select * From myfriends where ' + Fiel + ' like ''%'+Cond+'%'''
  else
    SQLText := 'Select * From myfriends where ' + Fiel + ' = '''+Cond+'''';
  try
    OpenSQL(DataForm.qrySource,SQLText);
  Except
    ShowMessage('访问数据库出错，查询失败。');
    Exit;
  end;
end;

end.