在欢迎页面显示长运行操作的进度

Question

我想在安装过程中检查我的应用程序更新，同时在 Inno Setup 的表单上显示该过程。

所以基本上是这样的：

WizardForm.WelcomeLabel2.Caption := 'Checking for update ...';
DownloadFile(VersionURL, LatestVersion)
WizardForm.WelcomeLabel2.Caption := 'New version available.';

下面是一个工作代码，除了当调用 CurPageChanged 时，表单还没有准备好。在完成新版本的检查之前，它不会正确显示。请参阅屏幕截图。使用调试器单步执行代码时工作正常。

我错过了什么？任何解决方法？
主要目的是避免在没有任何反馈的情况下等待版本检查过程，因为这感觉是不负责任的。

两张图片。

我得到的：
想要什么

#if defined UNICODE
  ; signed 64bit integer, but using only positive numbers, 0 .. 9223372036854775807
  ; examples of version string:
  ; 0..255 . 0..255 . 0..255 . 0..255 . 0..255 . 0..255 . 0..255 . 0..127
  ; 0..65535 . 0..65535 . 0..65535 . 0..32767
  #define Int64_OR_LongWord "Int64"
#else
  ; LongWord, 0 .. 4294967295
  ; 0..255 . 0..255 . 0..255 . 0..255
  ; 0..65535 . 0..65535
  #define Int64_OR_LongWord "LongWord"
#endif

[Setup]
AppName=Check Version
AppVersion=1.2.3
DefaultDirName={pf}\My Program

[Code]
const
  SetupURL = 'http://hu.hu/huhu.exe';
  VersionURL = 'http://hu.hu/version.txt';
  sizeNumOfSubsets=4;
  sizeSubset=256;

function VerStrToNum(const strVersion: String): {#Int64_OR_LongWord};
var strVersionRemaining: String;
    tmpIntSubset: Integer;
    i: Byte;
begin
  // add period at the end, so that any valid number should end with a period
  // empty strVersionRemaining means all numbers are read and the rest are zeroes
  // v1.2.3 = v1.2.3.0.0
  strVersionRemaining := AddPeriod(strVersion);
  for i := 1 to sizeNumOfSubsets do begin
    if strVersionRemaining <> '' then begin
      tmpIntSubset := StrToIntDef(Copy(strVersionRemaining,1, Pos('.',strVersionRemaining)-1), -1);
      strVersionRemaining := Copy(strVersionRemaining,Pos('.',strVersionRemaining)+1,Length(strVersionRemaining));
    end
    else tmpIntSubset := 0;   
    if tmpIntSubset <> -1 then begin
      Result := Result * sizeSubset + tmpIntSubset;
    end                                                
    else begin
      // if version string format invalid, just return 0,
      // error would just confuse user. RaiseException('Invalid format of version string');
      Result := 0;
      Exit;
    end;
  end;
end;

function DownloadFile(const URL: string; var Response: string): Boolean;
var
  WinHttpRequest: Variant;
begin
  Result := True;
  try
    WinHttpRequest := CreateOleObject('WinHttp.WinHttpRequest.5.1');
    WinHttpRequest.Open('GET', URL, False);
    WinHttpRequest.Send;
    Response := WinHttpRequest.ResponseText;
  except
    Result := False;
    Response := GetExceptionMessage;
  end;
end;


// --- to show correct text when comming back to Welcome Page by pressing PREV button
var oldWelcomeCaption: String;

function NextButtonClick(CurPageID: Integer): Boolean;
begin
  if CurPageID = wpWelcome then begin
    WizardForm.WelcomeLabel2.Caption := oldWelcomeCaption;
  end;
  Result := true
end;

var PanelDownloadButton: TPanel;

procedure CurPageChanged(CurPageID: Integer);
var LatestVersion: string;
begin
  case CurPageID of
    wpWelcome: begin
      // the Welcome Page was still hidden at this point
      WizardForm.Visible := True;
      // THIS IS WHAT I WAS MISSING:
      WizardForm.Repaint;
      oldWelcomeCaption := WizardForm.WelcomeLabel2.Caption;
      WizardForm.WelcomeLabel2.Caption := oldWelcomeCaption + #13 + #10 + #13 + #10 + #13 + #10 + #13 + #10 + #13 + #10 + #13 + #10 + 'Checking for update ...';
      if DownloadFile(VersionURL, LatestVersion) then begin
        if VerStrToNum(LatestVersion) > VerStrToNum('{#SetupSetting('AppVersion')}') then begin
          WizardForm.WelcomeLabel2.Caption := oldWelcomeCaption + #13 + #10 + #13 + #10 + #13 + #10 + #13 + #10 + #13 + #10 + #13 + #10 + 'New version available.';
          // PanelDownloadButton.Visible := True;
          // xxx Run downloaded setup, exit this one
        end
        else WizardForm.WelcomeLabel2.Caption := oldWelcomeCaption + #13 + #10 + #13 + #10 + #13 + #10 + #13 + #10 + #13 + #10 + #13 + #10 + 'No new versions.';
      end
      else WizardForm.WelcomeLabel2.Caption := WizardForm.WelcomeLabel2.Caption + #13 + #10 + Copy(LatestVersion,Pos(':',LatestVersion)+2,Length(LatestVersion));
    end;
  end;
end;

编辑： 上面的代码现已修复，以防有人想使用版本检查。
我将在带有按钮的最终代码中添加一个 link 并稍后下载功能。

Answer 1

调用WizardForm.Repaint强制表格完全绘制：

WizardForm.Visible := True;
WizardForm.Repaint;

见https://docwiki.embarcadero.com/Libraries/en/Vcl.Controls.TControl.Repaint

Forces the control to repaint its image on the screen.

Call Repaint to force the control to repaint its image immediately.

在欢迎页面显示长运行操作的进度

Display progress of long running operation on Welcome page

inno-setup

在欢迎页面显示长 运行 操作的进度

Display progress of long running operation on Welcome page

inno-setup

在欢迎页面显示长运行操作的进度