ContextStack Class

Definition

Namespace:

System.ComponentModel.Design.Serialization

Assembly:

System.ComponentModel.TypeConverter.dll

Source:

ContextStack.cs

Provides a stack object that can be used by a serializer to make information available to nested serializers.

public ref class ContextStack sealed

public sealed class ContextStack

type ContextStack = class

Public NotInheritable Class ContextStack

Inheritance

Object

ContextStack

Examples

The following code example demonstrates using a ContextStack to push and then remove 10 values.

#using <System.Windows.Forms.dll>
#using <System.dll>

using namespace System;
using namespace System::ComponentModel;
using namespace System::ComponentModel::Design;
using namespace System::ComponentModel::Design::Serialization;
using namespace System::Windows::Forms;

int main()
{
   // Create a ContextStack.
   ContextStack^ stack = gcnew ContextStack;
   
   // Push ten items on to the stack and output the value of each.
   for ( int number = 0; number < 10; number++ )
   {
      Console::WriteLine( "Value pushed to stack: {0}", number );
      stack->Push( number );
   }
   
   // Pop each item off the stack.
   Object^ item = nullptr;
   while ( (item = stack->Pop()) != 0 )
      Console::WriteLine( "Value popped from stack: {0}", item );
}

using System;
using System.ComponentModel;
using System.ComponentModel.Design;
using System.ComponentModel.Design.Serialization;
using System.Windows.Forms;

namespace ContextStackExample
{
    class ContextStackExample
    {
        [STAThread]
        static void Main(string[] args)
        {            
            // Create a ContextStack.
            ContextStack stack = new ContextStack();
            
            // Push ten items on to the stack and output the value of each.
            for( int number = 0; number < 10; number ++ )
            {
                Console.WriteLine( "Value pushed to stack: "+number.ToString() );
                stack.Push( number );
            }

            // Pop each item off the stack.
            object item = null;
            while( (item = stack.Pop()) != null )
                Console.WriteLine( "Value popped from stack: "+item.ToString() );
        }
    }
}

Imports System.ComponentModel
Imports System.ComponentModel.Design
Imports System.ComponentModel.Design.Serialization

Module ContextStackExample

    Sub Main()
        ' Create a ContextStack.
        Dim stack As New ContextStack

        ' Push ten items on to the stack and output the value of each.
        Dim number As Integer
        For number = 0 To 9
            Console.WriteLine(("Value pushed to stack: " + number.ToString()))
            stack.Push(number)
        Next number

        ' Pop each item off the stack.        
        Dim item As Object = stack.Pop()
        While item IsNot Nothing
            Console.WriteLine(("Value popped from stack: " + item.ToString()))
            item = stack.Pop()
        End While
    End Sub

End Module

Remarks

Some serializers require information about the context of an object to correctly persist their state. The ContextStack class enables a serializer to set data about the context of an object that is being serialized to a stack where another serializer can access it. The value of the Context property is provided by an IDesignerSerializationManager to share information of use to some serializers.

A context stack is useful because the process of serializing a design document can be deeply nested, and objects at each level of nesting may require context information to correctly persist the state of the object. A serializer can set a context object to the stack before invoking a nested serializer. Each object set to the stack should be removed by the serializer that set it after a call to a nested serializer returns.

Typically, the objects on the stack contain information about the context of the current object that is being serialized. A parent serializer adds context information to the stack about the next object to be serialized, calls an appropriate serializer and, when the serializer finishes executing on the object, removes the context information from the stack. It is up to the implementation of each serializer to determine what objects get pushed on this stack.

As an example, an object with a property named Enabled has a data type of Boolean. If a serializer writes this value to a data stream, it might need to include the context or type of property it is writing. The serializer does not have this information, however, because it is only instructed to write the Boolean value. To provide this information to the serializer, the parent serializer can push a PropertyDescriptor that points to the Enabled property on the context stack.

Constructors

ContextStack()

Initializes a new instance of the ContextStack class.

Properties

Current	Gets the current object on the stack.
Item[Int32]	Gets the object on the stack at the specified level.
Item[Type]	Gets the first object on the stack that inherits from or implements the specified type.

Methods

Append(Object)	Appends an object to the end of the stack, rather than pushing it onto the top of the stack.
Equals(Object)	Determines whether the specified object is equal to the current object. (Inherited from Object)
GetHashCode()	Serves as the default hash function. (Inherited from Object)
GetType()	Gets the Type of the current instance. (Inherited from Object)
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
Pop()	Removes the current object off of the stack, returning its value.
Push(Object)	Pushes, or places, the specified object onto the stack.
ToString()	Returns a string that represents the current object. (Inherited from Object)

See also

• IDesignerSerializationManager