提示这样的错误 求解决

[xiaowangbadandan]

bool mybool = false;
string mypassword;
do
{
Console.WriteLine("请输入你的姓名代号：");
Console.WriteLine("（1）张三，（2）李四，（3）王五");
//int myid = Convert.ToInt32(Console.ReadLine().Trim());
int myid = -1;
try
{
Convert.ToInt32(Console.ReadLine());
}
catch
{
}
if (myid = -1)
{
Console.WriteLine("你输入的有误");
}
else
{
switch (myid)
{
case 1: Console.WriteLine("请输入你的密码：");
mypassword = Console.ReadLine().Trim();
if (mypassword == "zhang")
{
Console.WriteLine("密码正确：");
mybool = true;
}
else
{
Console.WriteLine("密码错误！");
}
break;
case 2:
Console.WriteLine("请输入你的密码：");
mypassword = Console.ReadLine().Trim();
if (mypassword == "li")
{
Console.WriteLine("密码正确：");
mybool = true;
}
else
{
Console.WriteLine("密码错误!");
}
break;
case 3:
Console.WriteLine("请输入你的密码：");
mypassword = Console.ReadLine().Trim();
if (mypassword == "wang")
{
Console.WriteLine("密码正确：");
mybool = true;
}
else
{
Console.WriteLine("密码错误！");
}
break;
default:
Console.WriteLine("查无此人！");
break;
}
}
} while (!mybool);
Console.WriteLine("谢谢使用，系统退出.......\n按回车键退出！");
Console.ReadLine();


提示错误 无法将类型“int”隐士转换为“bool”

[sprc_lcl]

if (myid == -1)

[贫僧又回来了]

JF

[wsq279024988]

看看啊