ExpressionBuilderCollection Класс

Определение

public ref class ExpressionBuilderCollection sealed : System::Configuration::ConfigurationElementCollection

[System.Configuration.ConfigurationCollection(typeof(System.Web.Configuration.ExpressionBuilder))]
public sealed class ExpressionBuilderCollection : System.Configuration.ConfigurationElementCollection

[<System.Configuration.ConfigurationCollection(typeof(System.Web.Configuration.ExpressionBuilder))>]
type ExpressionBuilderCollection = class
    inherit ConfigurationElementCollection

Public NotInheritable Class ExpressionBuilderCollection
Inherits ConfigurationElementCollection

Наследование

Object

ConfigurationElement

ConfigurationElementCollection

ExpressionBuilderCollection

Атрибуты

ConfigurationCollectionAttribute

Примеры

В этом разделе приведены два примера кода. В первом примере показано, как декларативно указать значения для нескольких ExpressionBuilderCollection свойств класса. Второй демонстрирует, как использовать члены ExpressionBuilderCollection класса.

В следующем примере файла конфигурации показано, как декларативно указать значения для нескольких ExpressionBuilderCollection свойств класса.

<system.web>
  <compilation>
    <expressionBuilders>
      <add
        expressionPrefix="Resources"
        type="System.Web.Compilation.ResourceExpressionBuilder"/>
      <add
        expressionPrefix="ConnectionStrings"
        type="System.Web.Compilation.
        ConnectionStringsExpressionBuilder"/>
      <add expressionPrefix="AppSettings"
        type="System.Web.Compilation.AppSettingsExpressionBuilder" />
    </expressionBuilders>
  </compilation>
</system.web>

В следующем примере кода показано, как использовать члены ExpressionBuilderCollection класса.

#region Using directives

using System;
using System.Configuration;
using System.Web.Configuration;

#endregion

namespace Samples.Aspnet.SystemWebConfiguration
{
  class UsingExpressionBuildCollection
  {
    static void Main(string[] args)
    {
      try
      {
        // Set the path of the config file.
        string configPath = "";

        // Get the Web application configuration object.
        Configuration config =
          WebConfigurationManager.OpenWebConfiguration(configPath);

        // Get the section related object.
        CompilationSection configSection =
          (CompilationSection)config.GetSection("system.web/compilation");

        // Display title and info.
        Console.WriteLine("ASP.NET Configuration Info");
        Console.WriteLine();

        // Display Config details.
        Console.WriteLine("File Path: {0}",
          config.FilePath);
        Console.WriteLine("Section Path: {0}",
          configSection.SectionInformation.Name);

        // Create a new ExpressionBuilder reference.
        ExpressionBuilder myExpressionBuilder =
          new ExpressionBuilder("myCustomExpression", "MyCustomExpressionBuilder");
        // Add an ExpressionBuilder to the configuration.
        configSection.ExpressionBuilders.Add(myExpressionBuilder);

        // Add an ExpressionBuilder to the configuration.
        ExpressionBuilder myExpressionBuilder2 =
          new ExpressionBuilder("myCustomExpression2", "MyCustomExpressionBuilder2");
        configSection.ExpressionBuilders.Add(myExpressionBuilder2);

        // Display the ExpressionBuilder count.
        Console.WriteLine("ExpressionBuilder Count: {0}",
          configSection.ExpressionBuilders.Count);

        // Display the ExpressionBuildersCollection details.
        int i = 1;
        int j = 1;
        foreach (ExpressionBuilder expressionBuilder in configSection.ExpressionBuilders)
        {
          Console.WriteLine();
          Console.WriteLine("ExpressionBuilder {0} Details:", i);
          Console.WriteLine("Type: {0}", expressionBuilder.ElementInformation.Type);
          Console.WriteLine("Source: {0}", expressionBuilder.ElementInformation.Source);
          Console.WriteLine("LineNumber: {0}", expressionBuilder.ElementInformation.LineNumber);
          Console.WriteLine("Properties Count: {0}", expressionBuilder.ElementInformation.Properties.Count);
          j = 1;
          foreach (PropertyInformation propertyItem in expressionBuilder.ElementInformation.Properties)
          {
            Console.WriteLine("Property {0} Name: {1}", j, propertyItem.Name);
            Console.WriteLine("Property {0} Value: {1}", j, propertyItem.Value);
            ++j;
          }
          ++i;
        }

        // Remove an ExpressionBuilder.
        configSection.ExpressionBuilders.RemoveAt
          (configSection.ExpressionBuilders.Count-1);

        // Remove an ExpressionBuilder.
        configSection.ExpressionBuilders.Remove("myCustomExpression");

        // Update if not locked.
        if (!configSection.SectionInformation.IsLocked)
        {
          config.Save();
          Console.WriteLine("** Configuration updated.");
        }
        else
        {
          Console.WriteLine("** Could not update, section is locked.");
        }
      }

      catch (Exception e)
      {
        // Unknown error.
        Console.WriteLine(e.ToString());
      }

      // Display and wait.
      Console.ReadLine();
    }
  }
}

Imports System.Configuration
Imports System.Web.Configuration

Namespace Samples.Aspnet.SystemWebConfiguration
  Class UsingExpressionBuildCollection
    Public Shared Sub Main()
      Try
        ' Set the path of the config file.
        Dim configPath As String = ""

        ' Get the Web application configuration object.
        Dim config As System.Configuration.Configuration = _
         WebConfigurationManager.OpenWebConfiguration(configPath)

        ' Get the section related object.
        Dim configSection As System.Web.Configuration.CompilationSection = _
         CType(config.GetSection("system.web/compilation"), _
         System.Web.Configuration.CompilationSection)

        ' Display title and info.
        Console.WriteLine("ASP.NET Configuration Info")
        Console.WriteLine()

        ' Display Config details.
        Console.WriteLine("File Path: {0}", _
         config.FilePath)
        Console.WriteLine("Section Path: {0}", _
         configSection.SectionInformation.Name)

        ' Create a new ExpressionBuilder reference.
        Dim myExpressionBuilder As ExpressionBuilder = _
          New ExpressionBuilder("myCustomExpression", "MyCustomExpressionBuilder")
        ' Add an ExpressionBuilder to the configuration.
        configSection.ExpressionBuilders.Add(myExpressionBuilder)

        ' Add an ExpressionBuilder to the configuration.
        Dim myExpressionBuilder2 As ExpressionBuilder = _
         New ExpressionBuilder("myCustomExpression2", "MyCustomExpressionBuilder2")
        configSection.ExpressionBuilders.Add(myExpressionBuilder2)

        ' Display the ExpressionBuilder count.
        Console.WriteLine("ExpressionBuilder Count: {0}", _
          configSection.ExpressionBuilders.Count)

        ' Display the ExpressionBuildersCollection details.
        Dim i = 1
        Dim j = 1
        For Each expressionBuilder As ExpressionBuilder In configSection.ExpressionBuilders()
          Console.WriteLine()
          Console.WriteLine("ExpressionBuilder {0} Details:", i)
          Console.WriteLine("Type: {0}", expressionBuilder.ElementInformation.Type)
          Console.WriteLine("Source: {0}", expressionBuilder.ElementInformation.Source)
          Console.WriteLine("LineNumber: {0}", expressionBuilder.ElementInformation.LineNumber)
          Console.WriteLine("Properties Count: {0}", expressionBuilder.ElementInformation.Properties.Count)
          j = 1
          For Each propertyItem As PropertyInformation In expressionBuilder.ElementInformation.Properties
            Console.WriteLine("Property {0} Name: {1}", j, propertyItem.Name)
            Console.WriteLine("Property {0} Value: {1}", j, propertyItem.Value)
            j = j + 1
          Next
          i = i + 1
        Next

        ' Remove an ExpressionBuilder.
        configSection.ExpressionBuilders.RemoveAt _
         (configSection.ExpressionBuilders.Count - 1)

        ' Remove an ExpressionBuilder.
        configSection.ExpressionBuilders.Remove("myCustomExpression")

        ' Update if not locked.
        If Not configSection.SectionInformation.IsLocked Then
          config.Save()
          Console.WriteLine("** Configuration updated.")
        Else
          Console.WriteLine("** Could not update, section is locked.")
        End If

      Catch e As Exception
        ' Unknown error.
        Console.WriteLine(e.ToString())
      End Try

      ' Display and wait
      Console.ReadLine()
    End Sub
  End Class
End Namespace

Комментарии

Класс ExpressionBuilderCollection не ссылается на фактический элемент в базовом файле конфигурации. Это конструкция, которая позволяет легко получить доступ к содержащимся в ней сведениям о компиляции.

См. также раздел

• ExpressionBuilder
• ConfigurationElement