numedit.pas

一个只能处理数字的TEdit组件

unit NumEdit;

interface

uses
  SysUtils, Classes, Controls, StdCtrls;

type
  TNumEdit = class(TEdit)
  private
    { Private declarations }
    pPositive:boolean;
    pDeciNum:integer;

    FOnCustKeyPress: TKeyPressEvent;

   	function getvalue: Double;
   	procedure setvalue(Value: Double);

    function GetIntValue: integer;
    procedure SetIntValue(value: integer);

  protected
    { Protected declarations }
    procedure KeyPress(var Key: Char); override;
  public
    { Public declarations }
 			constructor create(aowner: TComponent); override;
			destructor Destroy; override;

  published
    { Published declarations }
    property Positive:boolean read pPositive write pPositive;
    property DeciNum:integer read pDeciNum write pDeciNum;
    property Value:double read getvalue write setvalue;
    property IntValue:integer read getIntvalue write setIntvalue;
    property OnCustKeyPress: TKeyPressEvent read FOnCustKeyPress write FOnCustKeyPress;
  end;

procedure Register;

implementation

uses Math;

procedure Register;
begin
  RegisterComponents('Standard', [TNumEdit]);
end;

{ TNumEdit }

constructor TNumEdit.create(aowner: TComponent);
begin
  inherited;
  ControlStyle := ControlStyle - [csSetCaption];
  pPositive:=true;
  pDeciNum:=4;
end;

destructor TNumEdit.Destroy;
begin

  inherited;
end;

function TNumEdit.GetIntValue: integer;
begin
  if Text='' then
  begin
    Result:=0;
    exit;
  end;
  try
    Result:=StrToInt(Text);
  Except
    Result:=0;
  end;

end;

function TNumEdit.getvalue: Double;
begin
  if Text='' then
  begin
    Result:=0;
    exit;
  end;
  try
    Result:=StrToFloat(Text);
  Except
    Result:=0;
  end;
end;

procedure TNumEdit.KeyPress(var Key: Char);
begin
  if ord(key)=8 then
  begin
    inherited;
    exit;
  end;
  if Key in ['0'..'9','.','-'] then
  begin

    if key='-' then
    begin
      if pPositive=true then
      begin
        key:=chr(0);
        exit;
      end;
      if SelStart<>0 then
      begin
        key:=chr(0);
        exit;
      end;
      if pos('-',Text)>0 then
      begin
        key:=chr(0);
        exit;
      end;
    end;

    if key='.' then
    begin
      if pos('.',Text)>0 then
      begin
        key:=chr(0);
        exit;
      end;
      if SelStart=0 then
      begin
        key:=chr(0);
        exit;
      end;
      if pos('-',Text)=1 then
      begin
        if SelStart=1 then
        begin
          key:=chr(0);
          exit;
        end;
      end;
    end;

    if key in ['0'..'9'] then
    begin
      if pos('-',Text)>0 then
      begin
        if SelStart=0 then
        begin
          key:=chr(0);
          exit;
        end;
      end;
      if pos('0',Text)=1 then
      begin
        if SelStart=1 then
        begin
          key:=chr(0);
          exit;
        end;
        if (key='0') and (selStart=0) then
        begin
          key:=chr(0);
          exit;
        end;
      end;
      if (pos('-',Text)=1) and (pos('0',Text)=2) then
      begin
        if (selstart=2) then
        begin
          key:=chr(0);
          exit;
        end;
        if (key='0') and  (SelStart=1) then
        begin
          key:=chr(0);
          exit;
        end;
      end;

      if pos('.',Text)>0 then
      begin
        if (Length(Text)-pos('.',Text))>=DeciNum then
        begin
          if SelStart>=Pos('.',Text) then
          begin
            key:=chr(0);
            exit;
          end;
        end;
      end;
    end;


    inherited;
    exit;
  end;

  if Assigned(FOnCustKeyPress) then
  	FOnCustKeyPress(self,Key);
    

  key:=chr(0);
exit;

end;

procedure TNumEdit.SetIntValue(value: integer);
begin
  Text:=IntToStr(Value);
end;

procedure TNumEdit.setvalue(Value: Double);
begin
  Text:=FloatToStr(Value);
end;

end.