C# 在c中启用多用户管理

在users表中，每个用户的MySql数据库可以用不同的颜色存储，例如：

Users       colors
Foo         green
Pluto       yellow
Foo         red

当用户通过身份验证时，我需要知道与登录的用户关联的颜色

我使用列表方法以这种方式为每个用户添加变量颜色：

List<string> colorList = new List<string>();

....

if (reader.HasRows)
{
    while (reader.Read())
    {
        Colors = reader["Colors"].ToString();
        colorList.Add(Colors.ToString());
    }

        ns = string.Join(", ", colorList.ToArray());
}

下面是我的代码

有人知道我该怎么做吗

你能推荐一下吗

你能帮我吗

先谢谢你

private DataSet RetrieveColors()
    {
        str = null;
        strArr = null;
        count = 0;

        str = ns == null ? "" : ns.ToString();
        char[] splitchar = { ',' };

        if (!string.IsNullOrEmpty(str))
        {
            strArr = str.Split(splitchar);
        }
        else
        {
            strArr = null;
        }

        for (count = 0; count <= strArr.Length - 1; count++)
        {
                sql = @" SELECT * FROM Experience WHERE Colors IN (?); ";
        }


        DataSet dsColors = new DataSet();

        using (OdbcConnection cn =
          new OdbcConnection(ConfigurationManager.ConnectionStrings["ConnMySQL"].ConnectionString))
        {
            cn.Open();

            using (OdbcCommand cmd = new OdbcCommand(sql, cn))
            {
                for (count = 0; count <= strArr.Length - 1; count++)
                {
                    cmd.Parameters.AddWithValue("param1", Server.UrlDecode(strArr[count].Trim()));
                }

                OdbcDataAdapter adapter = new OdbcDataAdapter(cmd);
                adapter.Fill(dsColors);
            }
        }

        return dsColors;
    }

请尝试以下代码：

sql = @" SELECT * FROM Experience WHERE Colors IN (?";

for (count = 1; count <= strArr.Length - 1; count++)
        {
                sql += ",?"; // add more placeholders as needed
        }
sql+=");"

请尝试以下代码：

sql = @" SELECT * FROM Experience WHERE Colors IN (?";

for (count = 1; count <= strArr.Length - 1; count++)
        {
                sql += ",?"; // add more placeholders as needed
        }
sql+=");"

---

请显示经验表列和预期输出的示例。@BlackBaron请参阅我的第一个问题中的编辑1。请显示经验表列和预期输出的示例。@BlackBaron请参阅我的第一个问题中的编辑1

sql = @" SELECT * FROM Experience WHERE Colors IN (?";

for (count = 1; count <= strArr.Length - 1; count++)
        {
                sql += ",?"; // add more placeholders as needed
        }
sql+=");"