读取和设置系统默认浏览器

系统默认浏览器是保存在注册表中，读取和设置需要操作注册表，但是在xp和win7（Vista及以上系统）下的位置是不同的，需要分别读取和设置；

读取系统默认浏览器：

Win7下：

function GetDefExplorerPathOnWin7(): string;
const
CPath = '%sshellopencommand';

var
oReg: TRegistry;
sKey, sPath: string;
begin
Result := '';
sKey := '';

oReg := TRegistry.Create();
try
oReg.RootKey := HKEY_CURRENT_USER;
if oReg.OpenKeyReadOnly('SoftwareMicrosoftWindowsShellAssociationsUrlAssociationshttpUserChoice') then
begin
sKey := Trim(oReg.ReadString('Progid'));
end;

if not SameText(sKey, '') then
begin
oReg.CloseKey;

oReg.RootKey := HKEY_CLASSES_ROOT;
sPath := Format(CPath, [sKey]);
if oReg.OpenKeyReadOnly(sPath) then
begin
Result := Trim(oReg.ReadString(''));
end;
end;
finally
oReg.CloseKey;
oReg.Free;
end;
end;

XP系统下：

function GetDefExplorerPathOnXP(): string;
var
oReg: TRegistry;
begin
Result := '';

oReg := TRegistry.Create();
try
oReg.RootKey := HKEY_CLASSES_ROOT;
if oReg.OpenKeyReadOnly('HTTPshellopencommand') then
begin
Result := Trim(oReg.ReadString(''));
end;
finally
oReg.CloseKey;
oReg.Free;
end;
end;

设置系统默认浏览器：

这里假设设置系统默认浏览器为IE，先将IE的路径读取到变量ABrowserPath中；

win7系统下：

procedure SetDefaultBrowerOnWin7();
var
oReg: TRegistry;
begin
oReg := TRegistry.Create();
try
oReg.RootKey := HKEY_CURRENT_USER;
if oReg.OpenKey('SoftwareMicrosoftWindowsShellAssociationsUrlAssociationshttpUserChoice', True) then
begin
oReg.WriteString('Progid', 'IE.HTTP');
end;

oReg.CloseKey();
finally
oReg.Free;
end;
end;

XP系统下：

procedure SetDefaultBrowerOnXP(const ABrowserPath: string);
var
oReg: TRegistry;
sValue: string;
begin
oReg := TRegistry.Create();
try
oReg.RootKey := HKEY_CLASSES_ROOT;
if oReg.OpenKey('HTTPshellopencommand', True) then
begin
sValue := Format('"%s" -- "%%1"', [ABrowserPath]);
oReg.WriteString('', sValue);
end;

oReg.CloseKey();
finally
oReg.Free;
end;
end;