C# 在 MySQL 查询上设置变量

Question

我现在正在编写 C# 函数，它必须返回我的用户密码。一切都很好，但是当我尝试编译这个项目时，VS 告诉我未分配的变量。

string sqlLoginCheck (string userId)
    {
        string database, host, user, pass, sqlParams, sqlQuery;
        string resultPassword;

        database = "db";
        host = "localhost";
        user = "root";
        pass = "....";

        sqlParams = "Database=" + database + ";Data Source=" + host + ";User Id=" + user + ";Password=" + pass;
        sqlQuery = "SELECT `id`, `name`, `pass` FROM `users` WHERE name = '" + userId + "' LIMIT 1";

        MySqlConnection sqlConnection = new MySqlConnection(sqlParams);
        MySqlCommand sqlCommand = new MySqlCommand(sqlQuery, sqlConnection);

        // Выполняем
        try
        {
            sqlConnection.Open();

            MySqlDataReader sqlReader = sqlCommand.ExecuteReader();

            if (sqlReader.HasRows)
            {
                while (sqlReader.Read())
                {
                    resultPassword = sqlReader[2].ToString();
                }
            }
            else
            {
                resultPassword = "";
            }
        }

        catch (MySqlException sqlError)
        {
            errorMessage.Text = "Ошибка: " + sqlError.Message;

            FileInfo errorLog = new FileInfo("errorLog.txt");

            if (errorLog.Exists == false)
            {
                FileStream errorFs = errorLog.Create();
                errorFs.Close();
            }

            StreamWriter errorSw = errorLog.AppendText();

            errorSw.WriteLine(DateTime.Now + " | " + sqlError.Message);
            errorSw.Close();
        }

        finally
        {
            sqlConnection.Close();
        }

        return resultPassword;

    }   

这里我不能返回resultPassword，因为变量未赋值:|

Answer 1

声明这个变量为

string resultPassword = null;

或者你可以声明为

string resultPassword = String.Empty;

在那种情况下你真的不需要

else
{
            resultPassword = "";
}

因为密码的默认值已经在声明时设置。