telegram-bot/Core/DbResolverParameter.cs

using System;
using BotFramework;
using Microsoft.EntityFrameworkCore;

namespace Kruzya.TelegramBot.Core;

/// <summary>
/// Resolves the GUIDs from database to entities.
/// </summary>
/// <typeparam name="TResolvedEntity">Entity type</typeparam>
/// <typeparam name="TAppContext">Database context where entity should be finded</typeparam>
public class DbResolverParameter<TResolvedEntity, TAppContext> : IParameterParser<TResolvedEntity>
    where TAppContext : DbContext
    where TResolvedEntity : class
{
    private TAppContext _dbContext;

    public DbResolverParameter(TAppContext dbContext)
    {
        _dbContext = dbContext;
    }
        
    public TResolvedEntity DefaultInstance()
    {
        return default(TResolvedEntity);
    }

    public bool TryGetValue(string text, out TResolvedEntity result)
    {
        result = null;
        Guid id;
        if (Guid.TryParse(text, out id))
        {
            result = _dbContext.Find<TResolvedEntity>(id);
            return (result != null);
        }

        return false;
    }
}