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Базы данных

Возврастающий поиск в DBGrid

Когда Вы заполняете DBGrid данными из запроса, Вы можете искать каждый столбец сетки с TEdit

Это простой проект:

unit U_Main; 
interface 
uses 
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs, 
  Db, DBTables, StdCtrls, Grids, DBGrids, ExtCtrls, DBCtrls; 
type 
  TFm_Main = class(TForm) 
    Panel1: TPanel; 
    Panel2: TPanel; 
    qry_Data: TQuery; 
    Ds_Data: TDataSource; 
    dbg_Data: TDBGrid; 
    Label1: TLabel; 
    Ed_Search: TEdit; 
    Database1: TDatabase; 
    qry_DataNUM_FACTURA: TStringField; 
    qry_DataF_FACTURA: TDateTimeField; 
    qry_DataM_DEVENGADO: TFloatField; 
    DBNavigator1: TDBNavigator; 
    procedure dbg_DataTitleClick(Column: TColumn); 
    procedure FormCreate(Sender: TObject); 
    procedure Ed_SearchChange(Sender: TObject); 
  private 
    FQueryStatement: string; 
    //Since for Alphanumeric Field you donґt need to validate nothing 
    //just keep a method pointer to the default Event Handler 
    FALphaNumericKeyPress: TKeyPressEvent; 
  public 
    property QueryStatement: string read FQueryStatement; 
    //Since we are going to search in various Fields wich DataType   
    //can be of diferent types, we must validate the user input on 
    //the OnkeyPress of the TEdit, but instead of building a super 
    //generic routine, lets make things simple. Build a separate 
    //method for each DataType you are interested in validate. 
    //I will only validate for Fields of type ftFloat, but you easily 
    //customize the code for your own needs.. 
    //Method Pointer for Fields of DataType ftFloat 
    procedure FloatOnKeyPress(Sender: TObject; var Key: Char); 
  end; 
var 
  Fm_Main: TFm_Main; 
implementation 
{$R *.DFM} 
procedure TFm_Main.dbg_DataTitleClick(Column: TColumn); 
var 
  vi_Counter: Integer; 
  vs_Field: String; 
begin 
  with dbg_Data do 
  begin 
    //First, deselect all the Gridґs Columns 
    for vi_Counter:=0 to Columns.Count-1 do 
      Columns[vi_Counter].Color := clWindow; 
    //Next "Select" the column the user has Clicked on 
    Column.Color := clTeal; 
    //Get the FieldName of the Selected Column 
    vs_Field := Column.FieldName; 
    //Order the Gridґs Data by the Selected column 
    with qry_Data do 
    begin 
      DisableControls; 
      Close; 
      SQL.Clear; 
      SQL.Text := QueryStatement + 'ORDER BY '+ vs_Field; 
      Open; 
      EnableControls; 
    end; 
    //Get the DataType of the selected Field and change the Editґs event 
    //OnKeyPress to the proper method Pointer 
    case Column.Field.DataType of 
      ftFloat: Ed_Search.OnKeyPress := FloatOnKeyPress; 
      else 
        Ed_Search.OnKeyPress := FALphaNumericKeyPress; 
    end; 
  end; 
end;//End of TFm_Main.dbg_DataTitleClick 
procedure TFm_Main.FloatOnKeyPress(Sender: TObject; var Key: Char); 
begin 
  if not(Key in ['0'..'9', #13, #8, #10, #46]) then 
    Key := #0; 
end;//End of TFm_Main.FloatOnKeyPress 
procedure TFm_Main.FormCreate(Sender: TObject); 
begin 
  //Keep a pointer for the default event Handler 
  FALphaNumericKeyPress := Ed_Search.OnKeyPress; 
  //Set the original Query SQL Statement 
  FQueryStatement := 'SELECT FIELD1, FIELD2, FIELD3 ' 
                     'FROM ANYTABLE '; 
  //Select the first Gridґs Column 
  dbg_DataTitleClick(dbg_Data.Columns[0]); 
end;//End of TFm_Main.FormCreate 
procedure TFm_Main.Ed_SearchChange(Sender: TObject); 
var 
  vi_counter: Integer; 
  vs_Field: String; 
begin 
  with dbg_Data do 
  begin 
    //First determine wich is the Selected Column 
    for vi_Counter:=0 to Columns.Count-1 do 
      if Columns[vi_Counter].Color = clTeal then 
      begin 
        vs_Field := Columns[vi_Counter].FieldName; 
        Break; 
      end; 
    //Locate the Value in the Query 
    with qry_Data do 
      case Columns[vi_Counter].Field.DataType of 
        ftFloat: Locate(vs_Field, StrToFloat(Ed_Search.Text), 
                [loCaseInsensitive, loPartialKey]); 
        else 
          Locate(vs_Field, Ed_Search.Text,[loCaseInsensitive, 
                 loPartialKey]); 
      end; 
  end; 
end;//End of TFm_Main.Ed_SearchChange 
end. 

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