C#學習經常使用類---ConfigurationManager類

提供對客戶端應用程序配置文件的訪問。 此類不能被繼承。

命名空間:                   System.Configuration
程序集:         System.Configuration（位於 System.Configuration.dll）

繼承層次結構

System.Object
System.Configuration.ConfigurationManager

public static class ConfigurationManager

屬性

	名稱	說明
	AppSettings	獲取當前應用程序默認配置的 AppSettingsSection 數據。
	ConnectionStrings	獲取當前應用程序默認配置的 ConnectionStringsSection 數據。

方法

	名稱	說明
	GetSection(String)	檢索當前應用程序默認配置的指定配置節。
	OpenExeConfiguration(ConfigurationUserLevel)	將當前應用程序的配置文件做爲 Configuration 對象打開。
	OpenExeConfiguration(String)	將指定的客戶端配置文件做爲 Configuration 對象打開。
	OpenMachineConfiguration()	將當前計算機的配置文件做爲 Configuration 對象打開。
	OpenMappedExeConfiguration(ExeConfigurationFileMap,ConfigurationUserLevel)	將指定客戶端配置文件做爲 Configuration 對象打開，該對象使用指定的文件映射和用戶級別。
	OpenMappedExeConfiguration(ExeConfigurationFileMap,ConfigurationUserLevel,Boolean)	將指定客戶端配置文件做爲 Configuration 對象打開，該對象使用指定的文件映射、用戶級別和預加載選項。
	OpenMappedMachineConfiguration(ConfigurationFileMap)	將計算機配置文件做爲 Configuration 對象打開，該對象使用指定的文件映射。
	RefreshSection(String)	刷新命名節，這樣在下次檢索它時將從磁盤從新讀取它。

備註

The T:System.Configuration.ConfigurationManager class enables you to access machine, application, and user configuration information. This class replaces the T:System.Configuration.ConfigurationSettings class, which is deprecated. For web applications, use the T:System.Web.Configuration.WebConfigurationManager class.

To use the T:System.Configuration.ConfigurationManager class, your project must reference the System.Configuration assembly. By default, some project templates, like Console Application, do not reference this assembly so you must manually reference it.

說明
The name and location of the application configuration file depend on the application's host. For more information, see NIB: Application Configuration Files.

You can use the built-in N:System.Configuration types or derive from them to handle configuration information. By using these types, you can work directly with configuration information and you can extend configuration files to include custom information.

The T:System.Configuration.ConfigurationManager class includes members that enable you to perform the following tasks:

• Read a section from a configuration file. To access configuration information, call the M:System.Configuration.ConfigurationManager.GetSection(System.String) method. For some sections such as appSettings and connectionStrings, use the P:System.Configuration.ConfigurationManager.AppSettings and P:System.Configuration.ConfigurationManager.ConnectionStrings classes. These members perform read-only operations, use a single cached instance of the configuration, and are multithread aware.

• Read and write configuration files as a whole. Your application can read and write configuration settings at any level, for itself or for other applications or computers, locally or remotely. Use one of the methods provided by the T:System.Configuration.ConfigurationManager class to open a configuration file such as SampleApp.exe.config. These methods return a T:System.Configuration.Configuration object that in turn exposes methods and properties you can use to work with the associated configuration files. The methods perform read or write operations and create the configuration data every time that a file is written.

• Support configuration tasks. The following types are used to support various configuration tasks:

  In addition to working with existing configuration information, you can create and work with custom configuration elements by extending the built-in configuration types such as the T:System.Configuration.ConfigurationElement, T:System.Configuration.ConfigurationElementCollection, T:System.Configuration.ConfigurationProperty, and T:System.Configuration.ConfigurationSection classes. For an example of how to extend a built-in configuration type programmatically, see T:System.Configuration.ConfigurationSection. For an example of how to extend a built-in configuration type that uses the attribute-based model, see T:System.Configuration.ConfigurationElement.

  • SectionInformation

  • PropertyInformation

  • PropertyInformationCollection

  • ElementInformation

  • ContextInformation

  • ConfigurationSectionGroup

  • ConfigurationSectionGroupCollection

實現函數說明：

The T:System.Configuration.Configuration class enables programmatic access for editing configuration files. You use one of the Open methods provided by T:System.Configuration.ConfigurationManager. These methods return a T:System.Configuration.Configuration object, which in turn provides the required methods and properties to handle the underlying configuration files. You can access these files for reading or writing.

To read the configuration files, use M:System.Configuration.Configuration.GetSection(System.String) or M:System.Configuration.Configuration.GetSectionGroup(System.String) to read configuration information. The user or process that reads must have the following permissions:

• Read permission on the configuration file at the current configuration hierarchy level.

• Read permissions on all the parent configuration files.

If your application needs read-only access to its own configuration, we recommend that you use the M:System.Configuration.ConfigurationManager.GetSection(System.String) method. This method provides access to the cached configuration values for the current application, which has better performance than the T:System.Configuration.Configuration class.

To write to the configuration files, use one of the Overload:System.Configuration.Configuration.Save methods. The user or process that writes must have the following permissions:

• Write permission on the configuration file and directory at the current configuration hierarchy level.

• Read permissions on all the configuration files.

示例

The first example shows a simple console application that reads application settings, adds a new setting, and updates an existing setting.

using System;
using System.Configuration;
namespace ConsoleApplication1
{    class Program
    {       
     static void Main(string[] args)
        {
            ReadAllSettings();
            ReadSetting("Setting1");
            ReadSetting("NotValid");
            AddUpdateAppSettings("NewSetting", "May 7, 2014");
            AddUpdateAppSettings("Setting1", "May 8, 2014");
            ReadAllSettings();
                    }        
        static void ReadAllSettings()
                {            
                try
            {                
            var appSettings = ConfigurationManager.AppSettings;     
            if (appSettings.Count == 0)
                {
                    Console.WriteLine("AppSettings is empty.");
                    } 
                else
                {                    
                foreach (var key in appSettings.AllKeys){
                        Console.WriteLine("Key: {0} Value: {1}",
                                          }
                }
            }           
             catch (ConfigurationErrorsException)
            {
                Console.WriteLine("Error reading app settings");
            }
        }        
        static void ReadSetting(string key)
        {            
        try
         {                
            var appSettings = ConfigurationManager.AppSettings;
            string result = appSettings[key] ?? "Not Found";
           Console.WriteLine(result);
            }            
            catch (ConfigurationErrorsException)
            {
                  Console.WriteLine("Error reading app settings");
            }
        }        
        static void AddUpdateAppSettings(string key, string value)
        {            
        try
        {                
 
 var configFile = ConfigurationManager.
 OpenExeConfiguration(ConfigurationUserLevel.None);
 var settings = configFile.AppSettings.Settings;                
         if (settings[key] == null)
               {
   settings.Add(key, value);
                
                }                
                else
                {
                    settings[key].Value = value;
                }
  configFile.Save(ConfigurationSaveMode.Modified);
  ConfigurationManager.RefreshSection(configFile.AppSettings.SectionInformation.Name);
            }            
            catch (ConfigurationErrorsException)
            {
                Console.WriteLine("Error writing app settings");
            }
        }
    }
}

The previous example assumes your project has an App.config file as shown below.

<?xml version="1.0" encoding="utf-8" ?><configuration>
    <startup> 
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
    </startup>
  <appSettings>
    <add key="Setting1" value="May 5, 2014"/>
    <add key="Setting2" value="May 6, 2014"/>
  </appSettings></configuration>

The following example shows how to use a connection string to read data from a database.

using System;using System.Configuration;
using System.Data.SqlClient;
namespace ConsoleApplication1
{    class Program
    {        
    static void Main(string[] args)
        {
            ReadProducts();
        }        
        static void ReadProducts()
        {           
var connectionString = ConfigurationManager.ConnectionStrings["WingtipToys"].
ConnectionString;      
      string queryString = "SELECT Id, ProductName FROM dbo.Products;";
            using (var connection = new SqlConnection(connectionString))
            {                
            var command = new SqlCommand(queryString, connection); 
         connection.Open();                
         using (var reader = command.ExecuteReader())
                {                    
                while (reader.Read())
              {
                        
    Console.WriteLine(String.Format("{0}, {1}", reader[0], reader[1]));
                    }
                }
            }
        }
    }
}

The previous example assumes your project has an App.config as shown below.

<?xml version="1.0" encoding="utf-8" ?><configuration>
    <startup> 
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
    </startup>
    <connectionStrings>
<add name="WingtipToys" connectionString="
Data Source=(LocalDB)\v11.0;Initial Catalog=WingtipToys;Integrated Security=True;
Pooling=False" />
    </connectionStrings></configuration>

備註：轉自https://msdn.microsoft.com/zh-cn/library/system.configuration.configurationmanager(v=vs.110).aspx