system.invalidoperationException：＆＃x27;连接属性不得为null＆＃x27;在MySQL连接中
在测试项目时，我遇到了错误 “ system.invalidoperationException：'连接属性必须是非零件 。 尝试解决错误，我编辑了数据库值并重新定义Enter_email和电子邮件条目。在网上寻找问题的原因，我找到了此错误的页面，但是，没有提到我的消息或发现它的原因。我将服务器信息放入一个单独的变量中。我不确定造成此错误的原因。有人可以向我解释吗？
给出错误的代码在这里：
async void LoginClick(object sender, EventArgs args)
{
var Server = "server=myip;user=app;database=travel_logger;port=3306;password=app; default command timeout=20;";
string enter_email = Email.Text;
using (var connection = new MySqlConnection(Server))
{
connection.Open();
var cmd = new MySqlCommand("SELECT _Password FROM * WHERE email=" + enter_email);
var reader = await cmd.ExecuteReaderAsync();
string data_password = reader.GetString(0);
if (data_password == Password.Text)
{
await Navigation.PushAsync(new AboutPage());
}
else
{
await DisplayAlert("Login Error", "Incorrect email or password","Okay");
}
connection.Close();
};
}
谢谢！
While Testing the project I came across the error "System.InvalidOperationException:'Connection property must be non-null.
Attempting to fix the error, I edited database values and re-defined enter_email and the Email Entry. Looking online to find the cause of the problem, I found the page for this error, however, no reference to my message or the cause of it was found. I placed the server info into a separate variable. I'm unsure of the cause of this error. Could anyone explain it to me?
The code giving the error is here:
async void LoginClick(object sender, EventArgs args)
{
var Server = "server=myip;user=app;database=travel_logger;port=3306;password=app; default command timeout=20;";
string enter_email = Email.Text;
using (var connection = new MySqlConnection(Server))
{
connection.Open();
var cmd = new MySqlCommand("SELECT _Password FROM * WHERE email=" + enter_email);
var reader = await cmd.ExecuteReaderAsync();
string data_password = reader.GetString(0);
if (data_password == Password.Text)
{
await Navigation.PushAsync(new AboutPage());
}
else
{
await DisplayAlert("Login Error", "Incorrect email or password","Okay");
}
connection.Close();
};
}
Thanks!
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这是投掷错误，因为您的命令不知道您的命令使用哪种连接。初始化时，您需要将连接传递到
mySqlCommand。It's throw error because your command doesn't know which connection your command use. You need to pass your connection to your
MySqlCommandwhen initialize.