Share View Controller of Share Extension Xamarin Version.

ShareviewController.cs

public override bool IsContentValid ()
{
     // Do validation of contentText and/or NSExtensionContext attachments here
     return true;
}
 
 public override void DidSelectPost ()
 {
      // This is called after the user selects Post. Do the upload of contentText and/or NSExtensionContext attachments.
      // Inform the host that we’re done, so it un-blocks its UI.      
      //Note: Alternatively you could call super’s -didSelectPost, which will similarly complete the extension context.
     ExtensionContext.CompleteRequest (new NSExtensionItem [0], null);
}
 
public override SLComposeSheetConfigurationItem [] GetConfigurationItems ()
{
     // To add configuration options via table cells at the bottom of the sheet, return an array of SLComposeSheetConfigurationItem here.
     return new SLComposeSheetConfigurationItem [0];
}