每个人都请帮助我。当我运行我的代码时。它给了我以下错误。
"Not allowed to change the connection string property.The connection current state is open."
这是我的代码。非常感谢任何帮助。我会等你的回复。谢谢你们所有人。
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;
using System.Data.SqlClient;
using System.Configuration;
using System.Data;
using RMSLibrary;
namespace RMS
{
public partial class InterfaceCityCountry : Window
{
CreateAgentAccount creatAgentWin = new CreateAgentAccount();
CitiesCountriesDAL citCountr = new CitiesCountriesDAL();
string str = ConfigurationManager.ConnectionStrings\
["RMSDatabaseSqlProvider"].ConnectionString;
public InterfaceCityCountry()
{
InitializeComponent();
CenterWindowOnScreen();
LoadListBoxCitiesCountries();
}
private void CenterWindowOnScreen()
{
double screenWidth = System.Windows.SystemParameters.PrimaryScreenWidth;
double screenHeight = System.Windows.SystemParameters.PrimaryScreenHeight;
double windowWidth = this.Width;
double windowHeight = this.Height;
this.Left = (screenWidth / 2) - (windowWidth / 2);
this.Top = (screenHeight / 2) - (windowHeight / 2);
}
private void LoadListBoxCitiesCountries()
{
try
{
citCountr.OpenConnection(str);
SqlDataAdapter sda = citCountr.GetCities();
DataSet ds = new DataSet();
sda.Fill(ds);
lbCities.ItemsSource = null;
lbCities.ItemsSource = ds.Tables[0].DefaultView;
SqlDataAdapter sda2 = citCountr.GetCountries();
DataSet ds2 = new DataSet();
sda2.Fill(ds2);
lbCountries.ItemsSource = null;
lbCountries.ItemsSource = ds2.Tables[0].DefaultView;
citCountr.CloseConnnection();
}
catch (Exception ex)
{
MyErrorMessage(ex);
}
finally
{
citCountr.CloseConnnection();
}
}
private void btnDeleteCity_Click(object sender, RoutedEventArgs e)
{
}
private void btnDeleteCountry_Click(object sender, RoutedEventArgs e)
{
}
private void MyErrorMessage(Exception ex)
{
string messageBoxText = "Error Occured! Try Again.\n\n" + ex.Message;
string caption = "Error";
MessageBoxButton button = MessageBoxButton.OK;
MessageBoxImage icon = MessageBoxImage.Error;
MessageBox.Show(messageBoxText, caption, button, icon);
}
private void lbCities_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
if (lbCities.SelectedIndex > -1)
{
tbCity.Text = ((DataRowView)lbCities.SelectedItem)
.Row.ItemArray[1].ToString();
btnUpdateCity.IsEnabled = true;
}
}
private void lbCountries_SelectionChanged
(object sender, SelectionChangedEventArgs e)
{
if (lbCountries.SelectedIndex > -1)
{
tbCountry.Text = ((DataRowView)lbCountries.SelectedItem)
.Row.ItemArray[1].ToString();
btnUpdateCountry.IsEnabled = true;
}
}
private void btnUpdateCity_Click(object sender, RoutedEventArgs e)
{
bool created = true;
DataClassesDataContext dc = new DataClassesDataContext();
try
{
string id = lbCities.SelectedValue.ToString();
if ((from c in dc.Cities where c.Name
== tbCity.Text select c).Count() == 1)
{
MessageBox.Show("Name already Exist. Choose a different name");
created = false;
}
else
{
var query = (from c in dc.Cities
where c.CityID == int.Parse(id)
select c).First();
query.Name = tbCity.Text;
dc.SubmitChanges();
}
}
catch(Exception ex)
{
created = false;
MyErrorMessage(ex);
}
if (created)
{
MessageBox.Show("Successfull");
tbCity.Text = string.Empty;
LoadListBoxCitiesCountries();
}
}
private void btnUpdateCountry_Click(object sender, RoutedEventArgs e)
{
bool created = true;
DataClassesDataContext dc = new DataClassesDataContext();
try
{
string id = lbCountries.SelectedValue.ToString();
if((from c in dc.Countries where
c.Name == tbCountry.Text select c).Count() == 1)
{
MessageBox.Show("Name already Exist. Choose a different name");
created = false;
}
else
{
var query = (from c in dc.Countries
where c.CountryID == int.Parse(id)
select c).First();
query.Name = tbCountry.Text;
dc.SubmitChanges();
}
}
catch (Exception ex)
{
created = false;
MyErrorMessage(ex);
}
if (created)
{
MessageBox.Show("Successfull");
tbCountry.Text = string.Empty;
LoadListBoxCitiesCountries();
}
}
private void City_CanExecute(object sender, CanExecuteRoutedEventArgs e)
{
bool hasError = Validation.GetHasError(tbCity);
e.CanExecute = !hasError;
}
private void City_Executed(object sender, ExecutedRoutedEventArgs e)
{
try
{
citCountr.OpenConnection(str);
if (!(citCountr.CheckAlreadyExistCity(tbCity.Text.Trim())))
{
citCountr.InsertCity(tbCity.Text.ToString().Trim());
LoadListBoxCitiesCountries();
citCountr.CloseConnnection();
MessageBox.Show("Added Successfully!");
creatAgentWin.LoadCitiesAndCountries();
tbCity.Text = "";
tbCountry.Text = "";
}
else
{
citCountr.CloseConnnection();
string msgtext = "City with same name
already exist. You can't add same city twice. Try with Different name!";
string caption = "Error";
MessageBoxButton button = MessageBoxButton.OK;
MessageBoxImage image = MessageBoxImage.Error;
MessageBox.Show(msgtext, caption, button, image).ToString();
}
}
catch (Exception ex)
{
string messageBoxText = "Error occured! Transection Failed. Try again";
string caption = "Error";
MessageBoxButton button = MessageBoxButton.OK;
MessageBoxImage icon = MessageBoxImage.Error;
MessageBox.Show(messageBoxText, caption, button, icon);
}
finally
{
citCountr.CloseConnnection();
}
}
private void Country_CanExecute(object sender, CanExecuteRoutedEventArgs e)
{
bool hasError = Validation.GetHasError(tbCountry);
e.CanExecute = !hasError;
}
private void Country_Executed(object sender, ExecutedRoutedEventArgs e)
{
try
{
citCountr.OpenConnection(str);
if (!(citCountr.CheckAlreadyExistCountry(tbCountry.Text.Trim())))
{
citCountr.InsertCountry(tbCountry.Text.ToString().Trim());
LoadListBoxCitiesCountries();
citCountr.CloseConnnection();
MessageBox.Show("Added Successfully!");
creatAgentWin.LoadCitiesAndCountries();
tbCity.Text = "";
tbCountry.Text = "";
}
else
{
citCountr.CloseConnnection();
string msgtext = "Country with
with same name already exist. You can't add
same country twice. Try with Different name!";
string caption = "Error";
MessageBoxButton button = MessageBoxButton.OK;
MessageBoxImage image = MessageBoxImage.Error;
MessageBox.Show(msgtext, caption, button, image).ToString();
}
}
catch (Exception ex)
{
this.MyErrorMessage(ex);
}
finally
{
citCountr.CloseConnnection();
}
}
}
}
答案 0 :(得分：1)
我已经修复了我的问题因为连接已经打开了。我已经用if else语句检查了我的连接，以找到连接打开的位置。 用于检查连接是否打开或关闭连接。使用以下代码
if (cn.State == ConnectionState.Open)
{
MessageBox.Show("open");
}
else {
MessageBox.Show("closed");
}
............................................... ............................................ 因此我把以下代码行
citCountr.CloseConnnection();
Before
citCountr.CloseConnnection();
我的问题消失了.................. 谢谢.........和快乐..................