客户端升级的时候,我们往往需要比较版本信息,如果当前版本已经是最新版本,则不需要再重新安装,并给用户做出提示信息。主要代码如下:
//此函数用于截取版本号数字
procedure DecodeVersion (verstr: String; var verint: array of Longint);
var
i,p: Longint; s: string;
begin
verint := [0,0,0,0];
i := 0;
while ((Length(verstr) > 0) and (i < 4)) do
begin
p := pos ('.', verstr);//分隔符“.”,eg:1.0.1.1
if p > 0 then
begin
if p = 1 then s:= '0' else s:= Copy (verstr, 1, p - 1);
verint[i] := StrToIntDef(s,-1);
i := i + 1;
verstr := Copy (verstr, p+1, Length(verstr));
end
else
begin
verint[i] := StrToIntDef(verstr,-1);
verstr := '';
end;
end;
end;
// 此函数用于比较版本字符串
// 若 ver1 > ver2 返回值??1
// 若 ver1 = ver2 返回值??0
// 若 ver1 < ver2 返回值 -1
function CompareVersion (ver1, ver2: String) : Integer;
var
verint1, verint2: array of Longint;
i: integer;
begin
SetArrayLength (verint1, 4);
DecodeVersion (ver1, verint1);
SetArrayLength (verint2, 4);
DecodeVersion (ver2, verint2);
Result := 0; i := 0;
while ((Result = 0) and (i < 4)) do
begin
if verint1[i] > verint2[i] then
Result := 1
else
if verint1[i] < verint2[i] then
Result := -1
else
Result := 0;
i := i + 1;
end;
end;
function InitializeSetup(): boolean;
var
regVersion: String;
begin
if RegQueryStringValue(HKLM, ExpandConstant('SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{#emit SetupSetting("AppId")}_is1'),
'DisplayVersion', regVersion) then
begin
// Successfully read the value
if CompareVersion(regVersion,ExpandConstant('{#ProductVerion}')) >= 0 then
begin
if WizardSilent() = false then //静默安装不弹窗
begin
MsgBox('当前已经是最新的版本', mbInformation, MB_OK);
end;
exit;
end;
end;
end;