发信人: lihai155(天琴)
整理人: teleme(2001-01-03 15:23:11), 站内信件
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unit FInput;
interface
uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
StdCtrls;
type
TFloatEdit = class(TEdit)
private
{ Private declarations }
Fracs:Integer; //小数位数
procedure MyChange(Sender:TObject);
procedure MyKeyPress(Sender: TObject; var Key: Char);
procedure SetFrac(const Value: Integer);
protected
{ Protected declarations }
public
{ Public declarations }
Constructor Create(AOwner:TComponent);override;
Destructor Destroy;override;
published
{ Published declarations }
property Frac:Integer Read Fracs Write SetFrac;
end;
procedure Register;
implementation
procedure Register;
begin
RegisterComponents('Samples', [TFloatEdit]);
end;
{ TEdit1 }
constructor TFloatEdit.Create(AOwner: TComponent);
begin
inherited;
OnChange:=MyChange;
OnKeyPress:=MyKeyPress;
Fracs:=2;
Text:='0';
end;
destructor TFloatEdit.Destroy;
begin
inherited;
end;
procedure TFloatEdit.MyChange(Sender: TObject);
begin
if Parent=nil then exit;
if Text = '' then exit;
try
if StrToFloat(Text)>922337203685477.5807 then
Begin
Application.MessageBox(PChar('数字太大。'),'错误',MB_OK);
Text:='';
End
except
Application.MessageBox(PChar('无效的数字。'),'错误',MB_OK);
Text :='';
End;
end;
procedure TFloatEdit.MyKeyPress(Sender: TObject; var Key: Char);
Var
NewText:String;
begin
if (Fracs=0) And (Key='.') then
Begin
Key:=#0;
Exit;
End;
if Not(Key in ['0'..'9']) And (Key<>Chr(VK_BACK)) And (Key<>'.') then
Begin
Key:=#0;
Exit;
End;
NewText:=Copy(Text,1,Self.SelStart-1)+Copy(Text,Self.SelStart+Self.SelLength,Length(Text));
if (Pos('.',NewText)>0) And (Key='.') then
Begin
Key:=#0;
Exit;
End;
NewText:=Copy(Text,1,Self.SelStart-1)+Key+Copy(Text,Self.SelStart+Self.SelLength,Length(Text));
if (Pos('.',NewText)>0) And (Length(NewText) - Pos('.',NewText)>Fracs) And
(Key in ['0'..'9']) then
Begin
Application.MessageBox(PChar('小数位数不能超过'+
IntToStr(Fracs)+'位。'),'错误',MB_OK);
Key:=#0;
End;
end;
procedure TFloatEdit.SetFrac(const Value: Integer);
begin
if Value<0 then
Application.MessageBox(PChar('小数位数不能为负数。'),'错误',MB_OK)
else
Fracs := Value;
end;
end.
//有什么改进意见欢迎回复，谢谢！
----
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