Unlike in Windows Phone apps, there is not a dedicated task
for composing email, instead, a general purpose launcher is used for launching
URIs. To launch an email client, a mailto: type URI can be used. The launching
itself is pretty much identical in C#, VB.Net, C++ and JavaScript; however the
text needs escaping to cope with spaces, carriage returns etc and this is where
the languages differ:
C#
In .Net for C# and VB.Net, the Uri class has a static method
‘EscapeUriString’ which takes care of escaping URI strings:
var email = string.Format(“mailto:{0}?subject={1}&body={2}”,
“email@somedomain.com",
"A Subject",
“The email body”);
var cleaned = Uri.EscapeUriString(email);
// Email
task
await Launcher.LaunchUriAsync(new Uri(cleaned, UriKind.Absolute));
VB.Net
Dim email = String.Format(SUPPORT_MAIL,
“email@somedomain.com",
"A Subject",
“The email body”)
Dim cleaned = Uri.EscapeUriString(email)
' Email task
Await Launcher.LaunchUriAsync(New Uri(cleaned, UriKind.Absolute))
JavaScript
WinRT JavaScript Uri object doesn’t have the ‘EscapeUriString’
method, however it supports the standard JavaScript encodeURI method which does
the same thing:
var email = "mailto:";
email += "email@somedomain.com";
email += "?subject=";
email += "A Subject";
email += "&body=";
email += "The email body";
var cleaned =
encodeURI(email);
// Email
task
var uri = new
Windows.Foundation.Uri(cleaned);
return Windows.System.Launcher.launchUriAsync(uri);
C++
WinRT JavaScript Uri object doesn’t have the ‘EscapeUriString’
method either and doesn’t have anything build in, so we need to write one
ourselves.
String^
email = L"mailto:";
email += "email@somedomain.com";
email += L"?subject=";
email += "A Subject";
email += L"&body=";
email += "The email body";
auto cleaned =
encodeURI(email);
auto uri = ref new Uri(cleaned);
Launcher::LaunchUriAsync(uri);
I found the main bit of this enclode function on Stack
Overflow (can’t find where now) and modified it to work with WinRT:
String^
encodeURI(String^ c)
{
const std::string unreserved = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_.~!*()\\,/?:@=+$&";
std::wstring escaped=L"";
for(size_t i=0; i<c->Length(); i++)
{
auto data = c->Data();
if (unreserved.find_first_of(data[i]) !=
std::string::npos)
{
escaped.push_back(data[i]);
}
else
{
escaped.append(L"%");
char buf[3];
sprintf_s(buf, "%.2X", data[i]);
auto s = std::string(buf);
auto w =
std::wstring(s.begin(), s.end());
escaped.append(w);
}
}
return ref new Platform::String(escaped.c_str());
}
