我有一个程序,底部有一个包含三个元素的状态栏.我想用不同的字体颜色重绘第二个元素,以表示用户有效.我的问题的第一部分是：
a)如何以不同的颜色将文本重绘为默认文本？
和b)如何在触发事件后以不同的颜色绘制文本(例如按下按钮)？
我目前的代码如下.我正在尝试检查以不同颜色重新绘制面板的条件是否正确(CurrentUser.Valid,这是一个布尔值),然后尝试重新着色文本.这目前不起作用.
procedure TChatFormMain.sbarMainDrawPanel(StatusBar: TStatusBar;
Panel: TStatusPanel; const Rect: TRect);
var
RectForText: TRect;
begin
if (Panel = StatusBar.Panels[1]) and (CurrentUser.Valid) then
begin
sbarMain.Canvas.Font.Color := clGreen;
RectForText := Rect;
StatusBar.Canvas.FillRect(RectForText);
DrawText(sbarMain.Canvas.Handle,PChar(Panel.Text),-1,RectForText,DT_SINGLELINE or DT_VCENTER or DT_LEFT);
end;
end;
在代码的另一部分,我正在调用StatusBar.repaint;尝试用新文本颜色重新绘制条形图,这是正确的吗？
更新MCVE：
unit colourStatusU;
interface
uses
Winapi.Windows,Winapi.Messages,System.SysUtils,System.Variants,System.Classes,Vcl.Graphics,Vcl.Controls,Vcl.Forms,Vcl.Dialogs,Vcl.StdCtrls,Vcl.ComCtrls;
type
TForm1 = class(TForm)
StatusBar1: TStatusBar;
Button1: TButton;
procedure Button1Click(Sender: TObject);
procedure StatusBar1DrawPanel(StatusBar: TStatusBar; Panel: TStatusPanel;
const Rect: TRect);
private
{ Private declarations }
public
{ Public declarations }
end;
var
Form1: TForm1;
valid : boolean;
implementation
{$R *.dfm}
procedure TForm1.Button1Click(Sender: TObject);
begin
valid := true;
StatusBar1.Repaint;
end;
procedure TForm1.StatusBar1DrawPanel(StatusBar: TStatusBar; Panel: TStatusPanel;
const Rect: TRect);
var
RectForText: TRect;
begin
if (Panel = StatusBar.Panels[1]) and (Valid) then
begin
Canvas.Font.Color := clGreen;
RectForText := Rect;
Canvas.FillRect(RectForText);
DrawText(Canvas.Handle,DT_SINGLELINE or DT_VCENTER or DT_LEFT);
end;
end;
end.
解决方法
OnDrawPanel事件仅针对其Style设置为psOwnerDraw的面板调用,因此请确保在Object Inspector或代码中正确设置了Style.
要绘制的画布必须是TStatusBar.Canvas,但您使用的是TForm.Canvas.使用OnDrawPanel事件提供的StatusBar的Canvas：
procedure TForm1.StatusBar1DrawPanel(StatusBar: TStatusBar; Panel: TStatusPanel;
const Rect: TRect);
var
RectForText: TRect;
begin
if (Panel = StatusBar.Panels[1]) and (Valid) then
begin
StatusBar.Canvas.Font.Color := clGreen;
RectForText := Rect;
StatusBar.Canvas.FillRect(RectForText);
DrawText(StatusBar.Canvas.Handle,DT_SINGLELINE or DT_VCENTER or DT_LEFT);
end;
end;