可以左右居中对齐并可设置DisplayFormat的Edit控件 (转)-优快云博客

介绍了一种自定义编辑控件，该控件支持左右居中对齐，并可设置显示格式，适用于浮点数、整数及任意类型的数据输入。通过重写绘图过程，实现了不同数据类型的输入限制及格式化显示。

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可以左右居中对齐并可设置DisplayFormat的Edit控件 (转)[@more@]

欢迎测试！

Mailto:liang_z@163.NET">liang_z@163.net

unit OWEdit;

interface

uses
windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
StdCtrls;

type
TInputDataType = (tFloat,tInteger,tAll);

type
TOWEdit = class(TEdit)
private
{ Private declarations }
FCanvas : TCanvas;
FDataType: TInputDataType;
FAlignment : TAlignment;
FDisplayFormat : String;
FDeciNum : word;
FDisplayText : String;
procedure WMPaint(var Message: TWMPaint); message WM_PAINT;
protected
{ Protected declarations }
procedure SetDataType(Value:TInputDataType);
procedure SetAlignment(Value:TAlignment);
procedure SetDisplayFormat(Value:String);
procedure ClipPaste(var M:TMessage); Message WM_PASTE;
procedure PaintWindow(DC: HDC); override;
procedure Paint; virtual;
procedure WMExit(var Message:TWMKillFocus);Message WM_KILLFOCUS;
procedure GetDisplayText;
procedure ShowDisplayText;
function GetDeciLast:integer;
public
{ Public declarations }
OldText : String;
property Text;
property Canvas: TCanvas read FCanvas;
constructor Create(AOwner: TComponent); override;
destructor Destroy(); override;
procedure KeyPress(var Key: Char); override;
procedure KeyDown(var Key: Word; Shift: TShiftState); override;
published
{ Published declarations }
property DataType: TInputDataType read fDataType write SetDataType default tFloat;
property Alignment: TAlignment read FAlignment write SetAlignment default taLeftJustify;
property DisplayFormat: string read FDisplayFormat write SetDisplayFormat;
end;

procedure Register;

implementation

procedure Register;
begin
RegisterComponents('Ourway', [TOWEdit]);
end;

constructor TOWEdit.Create(AOwner: TComponent);
begin
inherited Create(AOwner);
Text := '0';
FCanvas := TControlCanvas.Create;
TControlCanvas(FCanvas).Control := Self;
FDeciNum := 9999;
end;

destructor TOWEdit.Destroy();
begin
FCanvas.Free;
inherited Destroy();
end;

procedure TOWEdit.SetDataType(Value:TInputDataType);
begin
If Value<>fDataType Then
begin
fDataType := Value;
Case Value of
tAll: Text := '';
tFloat: Text:='0.0';
tInteger: Text:='0';
end;
ShowDisplayText;
Invalidate;
end;
end;

procedure TOWEdit.SetAlignment(Value:TAlignment);
begin
If Value<>FAlignment Then
begin
FAlignment := Value;
Invalidate;
end;
end;

procedure TOWEdit.SetDisplayFormat(Value: string);
begin
If Value<>FDisplayFormat Then
begin
FDisplayFormat := Value;
if Trim(Value)<>'' then
FDeciNum := Length(Value)-Pos('.',Value)+1
else
FDeciNum := 9999;
ShowDisplayText;
Invalidate;
end;
end;

procedure TOWEdit.KeyDown(var Key: Word; Shift: TShiftState);
begin
if Key = VK_DELETE then
if Self.SelStart=pos('.',Self.Text)-1 then
Key := 0;
inherited KeyDown(Key,Shift);
end;
procedure TOWEdit.KeyPress(var Key: Char);
var
kv: Integer;
begin
kv := Ord(Key);
case fDataType of
tInteger:
if (((kv>58) or (kv<48)) and (kv<>3) and (kv<>22) and (kv<>8) and (kv<>13)) then
Key := chr(0);
tFloat:
begin
if (((kv>58) or (kv<48)) and (kv<>3) and (kv<>22) and (kv<>46) and (kv<>8) and (kv<>13)) then
Key := chr(0)
else
begin
if (kv=46) and (Pos('.',self.Text)>0) then//已有小数点
Key := chr(0)
else
if MaxLength<1 then//小数点前面位数不定
begin
if ((GetDeciLast>=FDeciNum) and (kv<>8)) then //退格键
if ((self.SelLength=0)and(pos('.',copy(Self.Text,1,self.SelStart))>0))then
Key := chr(0);
end
else//输入总长度已定
begin
if pos('.',copy(self.Text,1,self.selStart))<1 then
begin//光标在小数点之前
if ((self.SelStart>=MaxLength-FDeciNum)and(kv<>8)and(kv<>46)) then
Key := chr(0);
end
else
begin//光标在小数点之后
if ((GetDeciLast>=FDeciNum) and (kv<>8) and (self.SelLength=0)and(pos('.',copy(Self.Text,1,self.SelStart))>0)) then
Key := chr(0);
end;
end;
end;
end;
else
end;
if (kv=8)and(Self.SelStart>0)and(Self.Text[self.SelStart]='.')and(GetDeciLast>1) then
Key := chr(0);
//还有一个Delete键没有截获！如果用此键删除小数点，还是有可能出错的。
//搞定！用KeyDown override
inherited KeyPress(Key);
end;

procedure TOWEdit.ClipPaste(var M:TMessage);
begin
if fDataType=tAll then
inherited;
end;

procedure TOWEdit.WMPaint(var Message: TWMPaint);
begin
inherited;
PaintWindow(Message.DC);
end;

procedure TOWEdit.PaintWindow(DC: HDC);
begin
FCanvas.Lock;
try
FCanvas.Handle := DC;
try
TControlCanvas(FCanvas).UpdateTextFlags;
Paint;
finally
FCanvas.Handle := 0;
end;
finally
FCanvas.Unlock;
end;
end;

procedure TOWEdit.Paint;
begin
if not Focused then
begin
ShowDisplayText;
end
else
inherited;
end;

procedure TOWEdit.WMExit(var Message:TWMKillFocus);
begin
inherited;
ShowDisplayText;
end;

procedure TOWEdit.GetDisplayText;
var
ShowText : String;
begin
ShowText := Text;
if FDataType<>tAll then
begin
if Trim(ShowText)='' then
ShowText := '0';
if FDatatype=tFloat then
ShowText := FormatFloat(FDisplayFormat,StrToFloat(ShowText))
else
ShowText := FormatFloat(FDisplayFormat,StrToInt(ShowText));
end;
FDisplayText := ShowText;
end;

procedure TOWEdit.ShowDisplayText;
var
Rect : TRect;
x,y : Integer;
begin
GetDisplayText;
Canvas.Lock;
try
Rect.Left := 1;
Rect.Top := 1;
Rect.Right := Width-1;
Rect.Bottom:= Height-1;
Canvas.Font := Font;
if not Enabled then
Canvas.Font.Color := clGrayText;
Canvas.Brush.Color:=Self.Color;
Canvas.FillRect(Rect);
y := 2; x := 2;
Case FAlignment of
taLeftJustify:;
taRightJustify:
x := Width-Canvas.TextWidth(FDisplayText)-5;
else
x := (Width-Canvas.TextWidth(FDisplayText)-5)div 2;
end;
Canvas.TextOut(x,y,FDisplayText);
finally
Canvas.Unlock;
end;
end;

function TOWEdit.GetDeciLast:integer;
var
i : Integer;
begin
Result := 0;
if Pos('.',Text)>0 then
begin
for i:=1 to Length(Text) do
if Text[i]='.' then
begin
Result := Length(Text)-i+1;//Length(Copy(Text,i,Length(Text)-i));
Exit;
end;
end;
end;

end.

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转载于:http://blog.itpub.net/10752043/viewspace-990038/