Validate a SQL Connection String

SqlConnectionStringValidator.cs

public static class SqlConnectionStringValidator
{
    public enum ErrorReason { None, ServerNetwork, Database, UserPassword, Other }

    public static bool TryValidateConnectionString(string server, string database, string user, string password, out string connectionString, out ErrorReason reason, out string message)
    {
        connectionString = default;

        if (!TryValidateValues(server, database, user, password, out reason, out message))
        {
            return false;
        }

        if (!TryBuildConnectionString(server, database, user, password, out connectionString, out reason, out message))
        {
            return false;
        }

        if (!TryValidateConnectionString(connectionString, out reason, out message))
        {
            return false;
        }

        return reason == ErrorReason.None;
    }

    private static bool TryValidateConnectionString(string connectionString, out ErrorReason reason, out string message)
    {
        reason = ErrorReason.None;
        message = default;

        try
        {
            using var connection = new SqlConnection(connectionString);
            connection.Open();
        }
        catch (SqlException ex) when (new[] { 53, 10060, 11001 }.Contains(ex.Number))
        {
            reason = ErrorReason.ServerNetwork;
            message = ex.Message;
        }
        catch (SqlException ex) when (ex.Number == 4060)
        {
            reason = ErrorReason.Database;
            message = ex.Message;
        }
        catch (SqlException ex) when (ex.Number == 18456)
        {
            reason = ErrorReason.UserPassword;
            message = ex.Message;
        }
        catch (Exception ex)
        {
            reason = ErrorReason.Other;
            message = ex.Message;
        }

        return reason == ErrorReason.None;
    }

    private static bool TryBuildConnectionString(string server, string database, string user, string password, out string connectionString, out ErrorReason reason, out string message)
    {
        connectionString = default;
        reason = ErrorReason.None;
        message = default;

        try
        {
            connectionString = new SqlConnectionStringBuilder
            {
                DataSource = server,
                InitialCatalog = database,
                UserID = user,
                Password = password
            }.ConnectionString;
        }
        catch (Exception ex)
        {
            reason = ErrorReason.Other;
            message = ex.Message;
        }

        return reason == ErrorReason.None;
    }

    private static bool TryValidateValues(string server, string database, string user, string password, out ErrorReason reason, out string message)
    {
        reason = ErrorReason.None;
        message = default;

        if (string.IsNullOrWhiteSpace(server))
        {
            reason = ErrorReason.ServerNetwork;
            message = "Server name is required";
        }
        else if (string.IsNullOrWhiteSpace(database))
        {
            reason = ErrorReason.Database;
            message = "Database name is required";
        }
        else if (string.IsNullOrWhiteSpace(user))
        {
            reason = ErrorReason.UserPassword;
            message = "User name is required";
        }
        else if (string.IsNullOrWhiteSpace(password))
        {
            reason = ErrorReason.UserPassword;
            message = "Password is required";
        }

        return reason == ErrorReason.None;
    }
}