# Basic Operations Questions ## How should I safely check a type? > [!WARNING] > Direct casting (e.g. `(Type)type`) is **the least recommended** > way of casting, as it *can* throw an [InvalidCastException] > when the object isn't the desired type. > > Please refer to [this post] for more details. In Discord.NET, the idea of polymorphism is used throughout. You may need to cast the object as a certain type before you can perform any action. A good and safe casting example: [!code-csharp[Casting](samples/basics/cast.cs)] [InvalidCastException]: https://docs.microsoft.com/en-us/dotnet/api/system.invalidcastexception [this post]: https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/types/how-to-safely-cast-by-using-as-and-is-operators ## How do I send a message? > [!TIP] > The [GetChannel] method by default returns an [IChannel]. > This means channels such as [IVoiceChannel], [ICategoryChannel] > can be returned. This is why that you cannot send message > to channels like those. Any implementation of [IMessageChannel] has a [SendMessageAsync] method. You can get the channel via [GetChannel] under the client. Remember, when using Discord.NET, polymorphism is a common recurring theme. This means an object may take in many shapes or form, which means casting is your friend. You should attempt to cast the channel as an [IMessageChannel] or any other entity that implements it to be able to message. [SendMessageAsync]: xref:Discord.IMessageChannel.SendMessageAsync* [GetChannel]: xref:Discord.WebSocket.DiscordSocketClient.GetChannel* ## How can I tell if a message is from X, Y, Z channel? You may check the message channel type. Visit [Glossary] to see the various types of channels. [Glossary]: Glossary.md#message-channels ## How can I get the guild from a message? There are 2 ways to do this. You can do either of the following, 1. Cast the user as an [IGuildUser] and use its [IGuild] property. 2. Cast the channel as an [IGuildChannel] and use its [IGuild] property. ## How do I add hyperlink text to an embed? Embeds can use standard [markdown] in the description field as well as in field values. With that in mind, links can be added with `[text](link)`. [markdown]: https://support.discordapp.com/hc/en-us/articles/210298617-Markdown-Text-101-Chat-Formatting-Bold-Italic-Underline- ## How do I add reactions to a message? Any entities that implement [IUserMessage] has an [AddReactionAsync] method. This method expects an [IEmote] as a parameter. In Discord.Net, an Emote represents a server custom emote, while an Emoji is a Unicode emoji (standard emoji). Both [Emoji] and [Emote] implement [IEmote] and are valid options. [!code-csharp[Emoji](samples/basics/emoji.cs)] [AddReactionAsync]: xref:Discord.IUserMessage.AddReactionAsync* ## Why am I getting so many preemptive rate limits when I try to add more than one reactions? This is due to how HTML header works, mistreating 0.25sec/action to 1sec. This casues the lib to throw preemptive rate limit more frequently than it should for methods such as adding reactions. ## Can I opt-out of preemptive rate limits? Unfortunately, not at the moment. See [#401](https://github.com/RogueException/Discord.Net/issues/401). [IChannel]: xref:Discord.IChannel [ICategoryChannel]: xref:Discord.ICategoryChannel [IGuildChannel]: xref:Discord.IGuildChannel [ITextChannel]: xref:Discord.ITextChannel [IGuild]: xref:Discord.IGuild [IVoiceChannel]: xref:Discord.IVoiceChannel [IGuildUser]: xref:Discord.IGuildUser [IMessageChannel]: xref:Discord.IMessageChannel [IUserMessage]: xref:Discord.IUserMessage [IEmote]: xref:Discord.IEmote [Emote]: xref:Discord.Emote [Emoji]: xref:Discord.Emoji