SiteMapProvider.Initialize(String, NameValueCollection) 方法

定义

命名空间:

System.Web

程序集:

System.Web.dll

初始化 SiteMapProvider 实现（包括从持久性存储区加载站点地图数据所需的任何资源）。

public:
 override void Initialize(System::String ^ name, System::Collections::Specialized::NameValueCollection ^ attributes);

public override void Initialize (string name, System.Collections.Specialized.NameValueCollection attributes);

override this.Initialize : string * System.Collections.Specialized.NameValueCollection -> unit

Public Overrides Sub Initialize (name As String, attributes As NameValueCollection)

参数

name

String

要初始化的提供程序的 Name。

attributes

NameValueCollection

NameValueCollection，其中可以包含附加特性以帮助初始化提供程序。 从 Web.config 文件中的站点地图提供程序配置读取这些特性。

示例

下面的代码示例演示如何重写 Initialize 方法以准备 Microsoft Access 数据库连接。

对象的OleDbConnection连接字符串在方法的参数Initialize中NameValueCollection传递。 在这种情况下，连接字符串由Web.config文件中特定于提供程序的部分提供。 此处， accessSiteMapConnectionString 包含托管站点映射数据的 Microsoft Access 数据库的连接字符串。

<siteMap defaultProvider="AccessSiteMapProvider">  
  <providers>  
     <add  
       name="AccessSiteMapProvider"  
       type="Samples.AspNet.AccessSiteMapProvider,Samples.AspNet"  
       accessSiteMapConnectionString="PROVIDER=MICROSOFT.JET.OLEDB.4.0;DATA SOURCE=\\SomeUNCShare\\sitemap.mdb"/>  
  </providers>   
 </siteMap>  

此代码示例是为类提供的大型示例的 SiteMapProvider 一部分。

   // Initialize is used to initialize the properties and any state that the
   // AccessProvider holds, but is not used to build the site map.
   // The site map is built when the BuildSiteMap method is called.
   virtual void Initialize( String^ name, NameValueCollection^ attributes ) override
   {
      if ( IsInitialized )
            return;

      StaticSiteMapProvider::Initialize( name, attributes );
      
      // Create and test the connection to the Microsoft Access database.
      // Retrieve the Value of the Access connection string from the
      // attributes NameValueCollection.
      String^ connectionString = attributes[ AccessConnectionStringName ];
      if ( nullptr == connectionString || connectionString->Length == 0 )
            throw gcnew Exception( "The connection string was not found." );
      else
            accessConnection = gcnew OleDbConnection( connectionString );

      initialized = true;
   }


protected:

// Initialize is used to initialize the properties and any state that the
// AccessProvider holds, but is not used to build the site map.
// The site map is built when the BuildSiteMap method is called.
public override void Initialize(string name, NameValueCollection attributes) {
    if (IsInitialized)
        return;

    base.Initialize(name, attributes);

    // Create and test the connection to the Microsoft Access database.

    // Retrieve the Value of the Access connection string from the
    // attributes NameValueCollection.
    string connectionString = attributes[AccessConnectionStringName];

    if (null == connectionString || connectionString.Length == 0)
        throw new Exception ("The connection string was not found.");
    else
        accessConnection = new OleDbConnection(connectionString);

    initialized = true;
}

' Initialize is used to initialize the properties and any state that the
' AccessProvider holds, but is not used to build the site map.
' The site map is built when the BuildSiteMap method is called.
Public Overrides Sub Initialize(ByVal name As String, ByVal attributes As NameValueCollection)
    If IsInitialized Then
        Return
    End If
    MyBase.Initialize(name, attributes)

    ' Create and test the connection to the Microsoft Access database.
    ' Retrieve the Value of the Access connection string from the
    ' attributes NameValueCollection.
    Dim connectionString As String = attributes(AccessConnectionStringName)

    If Nothing = connectionString OrElse connectionString.Length = 0 Then
        Throw New Exception("The connection string was not found.")
    Else
        accessConnection = New OleDbConnection(connectionString)
    End If
    initialized = True
End Sub

注解

该方法 Initialize 实际上不会生成网站地图，它只准备对象的状态 SiteMapProvider 以执行此操作。 默认实现从站点导航配置初始化 SecurityTrimmingEnabled 站点地图提供程序的属性。

派生自的 SiteMapProvider 类可以重写 Initialize 该方法，以初始化从永久性存储加载站点地图数据所需的任何状态和资源。 例如，如果派生类使用文件来存储站点地图数据，则可以在 Initialize 方法中执行任何文件初始化。 如果派生类使用某种其他类型的数据存储，例如关系数据库，则可能会执行初始化数据库连接。

ASP.NET 配置系统读取其他属性（如文件名或连接字符串），并使用其NameValueCollection参数传递给Initialize该方法。

继承者说明

在 Initialize(String, NameValueCollection) 派生类中重写方法时，在执行自己的初始化之前，请务必先调用 Initialize(String, NameValueCollection) 基类的方法。

另请参阅

• ProviderBase
• BuildSiteMap()
• Clear()