Validate Empty using C# expressions

ValidateEmpty.cs

// Usage ValidateEmpty(x => x.Id),

public static ValidationResult ValidateEmpty<T, TProp>(this T o, Expression<Func<T,TProp>> propertySelector)
{
    MemberExpression body = (MemberExpression)propertySelector.Body;
    var propInfo = body.Member as PropertyInfo;
    var value = propInfo?.GetValue(o, null);
        
    return value switch
    {
        null => new ValidationResult($"{body.Member.Name} is required", new[] {body.Member.Name}),
        string s => string.IsNullOrWhiteSpace(s)
            ? new ValidationResult($"{body.Member.Name} is required", new[] {body.Member.Name})
            : ValidationResult.Success,
        ICollection c => c.Count == 0
            ? new ValidationResult($"{body.Member.Name} is required", new[] {body.Member.Name})
            : ValidationResult.Success,
        _ => ValidationResult.Success
    };