pre-processing on the code before opening the intellisence

/// <summary>
/// Performs an auto-complete if the <see cref="SyntaxLanguage"/> supports an IntelliPrompt member list at the current offset.
/// </summary>
public class CustomIntelliPromptCompleteWordCommand : EditCommand {

    /// <summary>
    /// Executes the edit command.
    /// </summary>
    /// <param name="context">An <see cref="EditCommandContext"/> that holds context-related information.</param>
    public override void Execute(EditCommandContext context) {
        context.Document.ReplaceText([proper parameters here], ConvertCode([your text]));
        context.SyntaxEditor.Caret.Offset = [proper offset];
        SyntaxLanguage language = context.View.GetCurrentLanguageForContext();
        if ((language.IntelliPromptMemberListSupported) && (!context.Selection.IsReadOnly))
            language.IntelliPromptCompleteWord(context.SyntaxEditor);
    }

}

private string Header = "namespace MicroSaintSharp{\nclass Simulation{\npublic void Function()\n{";
private string Footer = "}\n}\n";

public override string Text
{
    get
    {
        int headerLength = Header.Length;
        int footerLength = Footer.Length;
        string baseText = base.Text;
        return baseText.Substring(Header, baseText.Length - headerLength - footerLength);
    }
    set
    {
        base.Text = Header + value + Footer;
    }
}