我已经编写了这段代码,并想知道如何从.config或.ini文件中调用某些数据。我已经研究了AppSettings和ConfigurationManager,但它对大脑来说太多了,无法计算:-)
我已将system.config引用类添加到引用类列表中。基本上,我希望MySQL的变量存储在一个外部文件中,最终用户稍后可以更改该文件。我不能把整个代码放进去,因为它说我已经超过3000行了。
DBServer = RemoteServer
dataBase = myDatabase
user = root
password = [the password here]
我已经用app.config尝试了以下代码,但仍然没有
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<connectionStrings>
<add name="constring" connectionString="server=localhost; database=SchoolDB; user id=root; password=Pa55w0rd;"/>
</connectionStrings>
</configuration>
替换主窗口中的以下内容。cs
string constring = "datasource=localhost;port=3306;username=root;password=Pa55w0rd";
用这个
string constring = ConfigurationManager.ConnectionStrings["dbconnectionstring"].ConnectionString;
然后我得到这个错误
"对象引用未设置为对象实例"
好的,这是主窗口。cs
public partial class Portal : Form
{
public Portal(string UserName)
{
InitializeComponent();
lbl_username.Text = UserName;
timer1.Start();
txt_staff_password1.PasswordChar = '*';
load_loan_laptops();
}
DataTable dbdataset;
void load_loan_laptops()
{
//string constring = "datasource=localhost;port=3306;username=root; password=Pa55w0rd";
string constring = ConfigurationManager.ConnectionStrings["constring"].ConnectionString;
string Query = "Select * from schooldb.loans where Avail = 'yes';";
MySqlConnection conDataBase = new MySqlConnection(constring);
MySqlCommand cmdDataBase = new MySqlCommand(Query, conDataBase);
MySqlDataReader myReader;
try
{
conDataBase.Open();
myReader = cmdDataBase.ExecuteReader();
while (myReader.Read())
{
string devices = myReader.GetString("Device_Name");
cmb_acer_loan.Items.Add(devices);
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
conDataBase.Close();
}
请有人帮忙解决这个问题。
问题:您的app.config
文件具有<connectionString>
标记,而不是<connectionStrings>
标记。
解决方案:在app.config
文件中用<connectionStrings>
替换<connectionString>
,用</connectionStrings>
替换</connectionString>
试试这个:
app.config
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<connectionStrings>
<add name="constring" connectionString="datasource=localhost;port=3306;username=root;password=Pa55w0rd"/>
</connectionStrings>
</configuration>
代码:
string constring = ConfigurationManager.ConnectionStrings["constring"].ConnectionString;