How do I use the IMvxComposeEmailTask interface in MvvmCross

1. Registering the Email Plugin

First, ensure that the MvvmCross Email plugin is installed in your project. You can add it via NuGet:

bash
Install-Package MvvmCross.Plugins.Email

For some versions of MvvmCross, especially during beta phases, you might need to manually register the plugin or override the `LoadPlugins` method in your platform-specific `Setup.cs` file. However, this is typically not required for stable versions.

2. Resolving the IMvxComposeEmailTask

To use the email functionality, you need to resolve an instance of `IMvxComposeEmailTask` from the MvvmCross IoC container. This can be done in your ViewModel or wherever you need to send an email:

csharp
using MvvmCross.Plugins.Email;

public class MyViewModel : MvxViewModel
{
    private readonly IMvxComposeEmailTask _emailTask;

    public MyViewModel(IMvxComposeEmailTask emailTask)
    {
        _emailTask = emailTask;
    }

    public void SendEmail()
    {
        _emailTask.ComposeEmail(
            to: "
 <script language='JavaScript' type='text/javascript'>
 <!--
 var prefix = 'm&#97;&#105;lt&#111;:';
 var suffix = '';
 var attribs = '';
 var path = 'hr' + 'ef' + '=';
 var addy91945 = 'r&#101;c&#105;p&#105;&#101;nt' + '&#64;';
 addy91945 = addy91945 + '&#101;x&#97;mpl&#101;' + '&#46;' + 'c&#111;m';
 document.write( '<a ' + path + '\'' + prefix + addy91945 + suffix + '\'' + attribs + '>' );
 document.write( addy91945 );
 document.write( '<\/a>' );
 //-->
 </script><script language='JavaScript' type='text/javascript'>
 <!--
 document.write( '<span style=\'display: none;\'>' );
 //-->
 </script>This e-mail address is being protected from spambots. You need JavaScript enabled to view it
 <script language='JavaScript' type='text/javascript'>
 <!--
 document.write( '</' );
 document.write( 'span>' );
 //-->
 </script>",
            cc: string.Empty,
            subject: "Hello from MvvmCross",
            body: "This is a test email.",
            isHtml: false);
    }
}

Alternatively, if you don't inject it via the constructor, you can resolve it directly from the IoC container:

csharp
var emailTask = Mvx.IoCProvider.Resolve();
emailTask.ComposeEmail(
    to: "
 <script language='JavaScript' type='text/javascript'>
 <!--
 var prefix = 'm&#97;&#105;lt&#111;:';
 var suffix = '';
 var attribs = '';
 var path = 'hr' + 'ef' + '=';
 var addy19663 = 'r&#101;c&#105;p&#105;&#101;nt' + '&#64;';
 addy19663 = addy19663 + '&#101;x&#97;mpl&#101;' + '&#46;' + 'c&#111;m';
 document.write( '<a ' + path + '\'' + prefix + addy19663 + suffix + '\'' + attribs + '>' );
 document.write( addy19663 );
 document.write( '<\/a>' );
 //-->
 </script><script language='JavaScript' type='text/javascript'>
 <!--
 document.write( '<span style=\'display: none;\'>' );
 //-->
 </script>This e-mail address is being protected from spambots. You need JavaScript enabled to view it
 <script language='JavaScript' type='text/javascript'>
 <!--
 document.write( '</' );
 document.write( 'span>' );
 //-->
 </script>",
    cc: string.Empty,
    subject: "Hello from MvvmCross",
    body: "This is a test email.",
    isHtml: false);

3. Handling Email Composition

When `ComposeEmail` is called, MvvmCross will attempt to open the default email client on the device with the specified details filled in. The user must then manually send the email.

Platform-Specific Considerations

- Windows UWP and WPF: The implementation is simplistic and uses the `mailto:` protocol to open the default email client. This means it will not work if no email client is installed or configured on the system.
- Xamarin.iOS and Xamarin.Android: These platforms typically handle email composition more robustly, opening the email client with the specified details.

Troubleshooting

If you encounter issues with the plugin not loading correctly, ensure that all MvvmCross libraries are on the same version. For older versions, you might need to manually register the plugin or adjust namespace settings as described in some bug reports[3].