ConfigurationManager读取配置文件

App.config文件有如下内容： 

<?xml version="1.0" encoding="utf-8" ?>

<configuration>

    <appSettings>

        <add key="userName" value="Gaby"/>

        <add key="password" value="12345"/>

    </appSettings>

    <connectionStrings>

        <add name="constr" connectionString="server=.;database=testDB;uid=sa;pwd=123"/>

    </connectionStrings>

</configuration>

AppSettingsSection 对象包含配置文件的 appSettings 节的内容

var userName = ConfigurationManager.AppSettings["username"];

var pwd = ConfigurationManager.AppSettings["password"];

注： 必须引入using System.Configuration的DLL。

 

读取数据库连接字符串connectionStrings 节的内容

 ConnectionStringSettingsCollection connections = ConfigurationManager.ConnectionStrings;

 var conStr = connections["constr"];

以下是返回集合：

// Show how to use ConnectionStrings.
static void DisplayConnectionStrings()
{
// Get the ConnectionStrings collection.
ConnectionStringSettingsCollection connections =
ConfigurationManager.ConnectionStrings;
Console.WriteLine();
Console.WriteLine("Connection strings:");
// Loop to get the collection elements.
IEnumerator conEnum =
connections.GetEnumerator();
int i = 0;
while (conEnum.MoveNext())
{
string name = connections[i].Name;
string connectionString = connections[name].ConnectionString;
string provider = connections[name].ProviderName;
Console.WriteLine("Name:               {0}", name);
Console.WriteLine("Connection string:  {0}", connectionString);
Console.WriteLine("Provider:           {0}", provider);
}
}