[英]How to write connection string in web.config file and read from it?
我正在嘗試像這樣將連接字符串寫入 Web.config:
<connectionStrings>
<add name="Dbconnection" connectionString="Server=localhost;
Database=OnlineShopping ; Integrated Security=True"/>
</connectionStrings >
並像這樣閱讀它:
string strcon =
ConfigurationManager.ConnectionStrings["Dbconnection"].ConnectionString;
SqlConnection DbConnection = new SqlConnection(strcon);
運行程序時,由於空引用而出現錯誤。 但是當我使用此代碼時:
SqlConnection DbConnection = new SqlConnection();
DbConnection.ConnectionString =
"Server=localhost; Database=OnlineShopping ; Integrated Security=True";
我沒有收到任何錯誤,程序正常運行! 問題是什么?
添加引用以添加System.Configuration
:-
System.Configuration.ConfigurationManager.
ConnectionStrings["connectionStringName"].ConnectionString;
您也可以更改 WebConfig 文件以包含提供程序名稱:-
<connectionStrings>
<add name="Dbconnection"
connectionString="Server=localhost; Database=OnlineShopping;
Integrated Security=True"; providerName="System.Data.SqlClient" />
</connectionStrings>
網頁配置:
<connectionStrings>
<add name="ConnStringDb" connectionString="Data Source=localhost;
Initial Catalog=DatabaseName; Integrated Security=True;"
providerName="System.Data.SqlClient" />
</connectionStrings>
代碼:
using System.Configuration;
using System.Data
SqlConnection _connection = new SqlConnection(
ConfigurationManager.ConnectionStrings["ConnStringDb"].ToString());
try
{
if(_connection.State==ConnectionState.Closed)
_connection.Open();
}
catch { }
您確定您的配置文件 (web.config) 位於正確的位置並且連接字符串確實在(生成的)文件中嗎? 如果您發布文件,則可能會復制 web.release.config 的內容。
配置和對連接字符串的訪問在我看來沒問題。 我總是會添加一個提供者名稱
<connectionStrings>
<add name="Dbconnection"
connectionString="Server=localhost; Database=OnlineShopping;
Integrated Security=True" providerName="System.Data.SqlClient" />
</connectionStrings>
在應用程序中打開 web.config 文件並像這樣在 connectionStrings 部分添加示例數據庫連接后試試這個
<connectionStrings>
<add name="yourconnectinstringName" connectionString="Data Source= DatabaseServerName; Integrated Security=true;Initial Catalog= YourDatabaseName; uid=YourUserName; Password=yourpassword; " providerName="System.Data.SqlClient"/>
</connectionStrings >
試試這個
var configuration = WebConfigurationManager.OpenWebConfiguration("~");
var section = (ConnectionStringsSection)configuration.GetSection("connectionStrings");
section.ConnectionStrings["MyConnectionString"].ConnectionString = "Data Source=...";
configuration.Save();
嘗試使用WebConfigurationManager
而不是ConfigurationManager
在應用程序中打開 web.config 文件后,在 connectionStrings 部分添加示例數據庫連接,如下所示:
<connectionStrings>
<add name="yourconnectinstringName" connectionString="Data Source= DatabaseServerName; Integrated Security=true;Initial Catalog= YourDatabaseName; uid=YourUserName; Password=yourpassword; " providerName="System.Data.SqlClient" />
</connectionStrings>
在 web.config 文件中聲明 connectionStrings:
<add name="dbconnection" connectionString="Data Source=Soumalya;Integrated Security=true;Initial Catalog=MySampleDB" providerName="System.Data.SqlClient" />
無需用戶名和密碼即可訪問數據庫服務器。 現在,編寫代碼以從我們的代碼隱藏文件中的 web.config 文件中獲取連接字符串。 在代碼隱藏文件中添加以下命名空間。
using System.Configuration;
此命名空間用於從 web.config 文件中獲取配置節詳細信息。
using System;
using System.Data.SqlClient;
using System.Configuration;
public partial class _Default: System.Web.UI.Page {
protected void Page_Load(object sender, EventArgs e) {
//Get connection string from web.config file
string strcon = ConfigurationManager.ConnectionStrings["dbconnection"].ConnectionString;
//create new sqlconnection and connection to database by using connection string from web.config file
SqlConnection con = new SqlConnection(strcon);
con.Open();
}
}
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