C# 在 asp.net 中从 Web.config 获取连接字符串

Get Connection String from Web.config in asp.net

提问by Ammar Asjad

I want to know the ways to get connection string from web.config file in asp.net.

我想知道从asp.net 中的web.config 文件获取连接字符串的方法。

I just only know the below way .

我只知道下面的方法。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Configuration;

    namespace Sherserve.DataAccessLayer
    {
        public class DBGateway
        {
            public static string conString;

            public DBGateway()
            {
                conString = ConfigurationManager.ConnectionStrings["test"].ToString();
            }
        }
    }

采纳答案by Shadow Wizard is Ear For You

Using the ConfigurationManager.ConnectionStringsis about the only proper way, to use it properly with sanity check you can have such code:

使用ConfigurationManager.ConnectionStringsis 是唯一正确的方法，要通过健全性检查正确使用它，您可以拥有这样的代码：

public DBGateway()
{
    ConnectionStringSettings mySetting = ConfigurationManager.ConnectionStrings["test"];
    if (mySetting == null || string.IsNullOrEmpty(mySetting.ConnectionString))
        throw new Exception("Fatal error: missing connecting string in web.config file");
    conString = mySetting.ConnectionString;
}

This will throw useful error in case the connection string is missing, instead of cryptic "null object" error.

如果连接字符串丢失，这将抛出有用的错误，而不是神秘的“空对象”错误。

Worth to mention that the ConnectionStringSettingsclass is overriding the ToString()method:

值得一提的是，ConnectionStringSettings该类正在覆盖该ToString()方法：

public override string ToString()
{
    return this.ConnectionString;
}

So it means that using ConfigurationManager.ConnectionStrings["test"].ToString()is the same like ConfigurationManager.ConnectionStrings["test"].ConnectionStringhowever you still better perform sanity check and personally it looks cleaner to use the actual property and not depend on the class to give it.

所以这意味着 usingConfigurationManager.ConnectionStrings["test"].ToString()是一样的，ConfigurationManager.ConnectionStrings["test"].ConnectionString但是你仍然可以更好地执行健全性检查，而且就个人而言，使用实际属性看起来更干净，而不是依赖于提供它的类。

回答by RL89

Here is the whole solution:-

这是整个解决方案：-

string constring = System.Configuration.ConfigurationManager.ConnectionStrings["ConnectionStringName"].ConnectionString;
SqlConnection con = new SqlConnection(constring);
DataSet ds = new DataSet();
try
 {
   SqlDataAdapter dataAdapter = new SqlDataAdapter(query, con);
   SqlCommandBuilder commandBuilder = new SqlCommandBuilder(dataAdapter);
   con.Open();
   dataAdapter.Fill(ds, "table");
   return ds;
 }
 catch (Exception ex)
  {
  }
    finally
    {
        if (con.State == System.Data.ConnectionState.Open)
            con.Close();
    }

This is how you can fetch records from database into datatable.

这就是您如何从数据库中获取记录到数据表中的方法。

Hope this is what you were looking for.

希望这就是你要找的。

回答by mRizvandi

I have a method on my WebAssistant Class. i have a key on appSettings that contain my WebAppName, check the below line:

我的 WebAssistant 类上有一个方法。我在 appSettings 上有一个包含我的 WebAppName 的密钥，请检查以下行：

<add key="DOMAIN_NAME" value="mRizvandi.com"/>

and my connection name alwyas has "DomainName"+"DBConnectionString" template such as:

并且我的连接名称 alwyas 具有“DomainName”+“DBConnectionString”模板，例如：

<add name="mRizvandiDBConnectionString" connectionString=...

Ok, everything are ready to get connectionstring without pass any string.

好的，一切准备就绪，无需传递任何字符串即可获取连接字符串。

    public static string GetDBConnectionString()
    {
        string retValue = "";
        string domainUrl = "";
        string connectionKey = "";
        string dbConnectionString = "";

        domainUrl = GetDomainUrl();
        connectionKey = domainUrl.Substring(0, domainUrl.IndexOf(".")) + "DBConnectionString";
        dbConnectionString = System.Configuration.ConfigurationManager.ConnectionStrings[connectionKey].ToString();
        retValue = dbConnectionString;

        return retValue;
    }

I hope would be helpful.

我希望会有所帮助。

回答by Carlos E

Following code works for me. I've added the exception in case connectionString not founded in web.config

以下代码对我有用。我在 web.config 中没有建立 connectionString 的情况下添加了例外

web.config:

网络配置：

 <configuration>
  <connectionStrings>
    <add name="DBConnection" connectionString="Data Source=myaddress;Initial Catalog=MyCatalog;User ID=myuser;Password=pass;Encrypt=True;TrustServerCertificate=False"
         providerName="System.Data.SqlClient" />
  </connectionStrings>
</configuration>

In my connection class:

在我的连接类中：

static internal string GetSqlConnectionString(){

try {
    ConnectionStringSettings mySetting = ConfigurationManager.ConnectionStrings("DataBaseConnection");
    if (mySetting == null)
        throw new Exception("Database connection settings have not been set in Web.config file");

    return mySetting.ConnectionString;

} catch (Exception ex) {
    throw;
}}

回答by K.M.

Try

尝试

 string ConString = System.Configuration.ConfigurationManager.ConnectionStrings[ConfigurationManager.ConnectionStrings.Count -1].ConnectionString;