Delphi备忘录

1. 　　第三方控件之DBGridEh排序处理：

　1.1.　　添加引用:DBClient；

　1.2.　　置DBGridEh控件属性:

　    1.2.1.　设置dghAutoSortMarking属性为True;

　    1.2.2. 　设置希望排序的Column的TitleButton属性为True.

    1.3.　　在DBGridEh的OnTitleClick事件中添加代码：

　

  IF Column.Title.SortMarker = smdowneh THEN
    ADOQUERY1.Sort := Column.FieldName
  else
    ADOQUERY1.Sort := Column.FieldName + ' DESC';

2.　　DBGridEh需注意的几个重要属性设置：

　  2.1.　　dgEditing:=False;(通常情况下在当前控件中不允许编辑)

　  2.2.　　dgRowSelect:=True;

      2.3.　　dgAlwaysShowSelection:=Ture;

3.　　小数点处理：

　　Frac(a); //取小数部分
　　trunc(a); //截断
　　Round(a); //四舍五入

示例代码如下：

procedure TForm1.btn_1Click(Sender: TObject);
var
  a,b,c,d:Double;
begin
  a := 8.59;
  b := Frac(a);    //取小数部分0.59
  c := trunc(a);   //截断8
  d := Round(a);   //四舍五入9
  ShowMessage('取小数部分'+FloatToStr(b)+'  '+'截断'+ FloatToStr(c) + '  '+'四舍五入'+Floattostr(d) );
end;

4.　　DBGridEh 与 StringGrid用法示例

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, Grids, DBGridEh, DB, ADODB,DBClient;

type
  TForm1 = class(TForm)
    dbgrdh1: TDBGridEh;
    strngrd1: TStringGrid;
    btn1: TButton;
    btn2: TButton;
    btn3: TButton;
    edt1: TEdit;
    con1: TADOConnection;
    ds1: TDataSource;
    procedure btn3Click(Sender: TObject);
    procedure btn1Click(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
    procedure btn2Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure dbgrdh1TitleClick(Column: TColumnEh);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  viewSql:string;
  dbqry:TADOQuery;
  strqry:TADOQuery;
implementation

{$R *.dfm}

procedure TForm1.btn3Click(Sender: TObject);
begin
  Application.Terminate;
end;

procedure TForm1.btn1Click(Sender: TObject);
begin
  viewSql:=' SELECT RKEY,PROD_CODE,PRODUCT_NAME,PR_GRP_POINTER,LEAD_TIME, '
            +' OPT_LOT_SIZE,MAX_DAYS_EARLY_BUILD,PROD_SEEDVALUE,PROD_INCREMENTBY '
          +' FROM tb_Demo '
          +' WHERE 1=1 ' ;
  if Trim(edt1.Text)<>'' then
     viewSql:=viewSql + ' AND PRODUCT_NAME LIKE '
                      + QuotedStr('%'+edt1.Text+'%');

  dbqry:=TADOQuery.Create(nil);
  dbqry.Connection:=con1;
  with dbqry do
  begin
    Close;
    SQL.Clear;
    SQL.Add(viewSql);
    Open;
  end;
  ds1.DataSet:=dbqry;
  dbgrdh1.DataSource:=ds1;
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
  dbqry.Free;
end;

procedure TForm1.btn2Click(Sender: TObject);
var
   i:Integer;
begin
  viewSql:=' SELECT RKEY,PROD_CODE,PRODUCT_NAME '
          +' FROM tb_Demo '
          +' WHERE PROD_CODE LIKE '+ QuotedStr('B/B%') ;
  strqry:=TADOQuery.Create(nil);
  strqry.Connection:=con1;
  with strqry do
  begin
    Close;
    SQL.Clear;
    SQL.Add(viewSql);
    Open;
  end;

  strngrd1.RowCount:=strqry.RecordCount;
  strqry.First;
  while not strqry.Eof do
  begin
    for i:=1 to strngrd1.RowCount + 1 do
    begin
      strngrd1.Cells[0,i]:=strqry.fieldbyname('RKEY').AsVariant;
      strngrd1.Cells[1,i]:=strqry.fieldbyname('PROD_CODE').AsString;
      strngrd1.Cells[2,i]:=strqry.fieldbyname('PRODUCT_NAME').AsString;

      strqry.Next;
    end;
  end;

end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  strngrd1.Cells[0,0]:='RKEY';
  strngrd1.Cells[1,0]:='PROD_CODE';
  strngrd1.Cells[2,0]:='PRODUCT_NAME';

  strngrd1.ColWidths[0]:=60;
  strngrd1.ColWidths[1]:=100;
  strngrd1.ColWidths[2]:=200;
end;

end.