SessionParameter Class

.NET Framework (current version)

Other Versions

Binds the value of a session variable to a parameter object.

Namespace: System.Web.UI.WebControls
Assembly: System.Web (in System.Web.dll)

Inheritance Hierarchy

System.Object
System.Web.UI.WebControls.Parameter
System.Web.UI.WebControls.SessionParameter

Syntax

C++

type SessionParameter = 
    class
        inherit Parameter
    end

Constructors

	Name	Description
	SessionParameter()	Initializes a new unnamed instance of the SessionParameter class.
	SessionParameter(SessionParameter)	Initializes a new instance of the SessionParameter class with the values of the instance specified by the original parameter.
	SessionParameter(String, DbType, String)	Initializes a new instance of the SessionParameter class, by using the specified name and type, and binding the parameter to the specified session state name/value pair. This constructor is for database types.
	SessionParameter(String, String)	Initializes a new named instance of the SessionParameter class, using the specified string to identify which session state name/value pair to bind to.
	SessionParameter(String, TypeCode, String)	Initializes a new named and strongly typed instance of the SessionParameter class, using the specified string to identify which session state name/value pair to bind to.

Properties

	Name	Description
	ConvertEmptyStringToNull	Gets or sets a value indicating whether the value that the Parameter object is bound to should be converted to null if it is String.Empty.(Inherited from Parameter.)
	DbType	Gets or sets the database type of the parameter.(Inherited from Parameter.)
	DefaultValue	Specifies a default value for the parameter, should the value that the parameter is bound to be uninitialized when the Evaluate method is called.(Inherited from Parameter.)
	Direction	Indicates whether the Parameter object is used to bind a value to a control, or the control can be used to change the value.(Inherited from Parameter.)
	IsTrackingViewState	Gets a value indicating whether the Parameter object is saving changes to its view state.(Inherited from Parameter.)
	Name	Gets or sets the name of the parameter.(Inherited from Parameter.)
	SessionField	Gets or sets the name of the session variable that the parameter binds to.
	Size	Gets or sets the size of the parameter.(Inherited from Parameter.)
	Type	Gets or sets the type of the parameter.(Inherited from Parameter.)
	ViewState	Gets a dictionary of state information that allows you to save and restore the view state of a Parameter object across multiple requests for the same page.(Inherited from Parameter.)

Methods

	Name	Description
	Clone()	Returns a duplicate of the current SessionParameter instance.(Overrides Parameter.Clone().)
	Equals(Object)	Determines whether the specified object is equal to the current object.(Inherited from Object.)
	Evaluate(HttpContext, Control)	Updates and returns the value of the SessionParameter object.(Overrides Parameter.Evaluate(HttpContext, Control).)
	Finalize()	Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.(Inherited from Object.)
	GetDatabaseType()	Gets the DbType value that is equivalent to the CLR type of the current Parameter instance.(Inherited from Parameter.)
	GetHashCode()	Serves as the default hash function. (Inherited from Object.)
	GetType()	Gets the Type of the current instance.(Inherited from Object.)
	LoadViewState(Object)	Restores the data source view's previously saved view state.(Inherited from Parameter.)
	MemberwiseClone()	Creates a shallow copy of the current Object.(Inherited from Object.)
	OnParameterChanged()	Calls the OnParametersChanged method of the ParameterCollection collection that contains the Parameter object.(Inherited from Parameter.)
	SaveViewState()	Saves the changes to the Parameter object's view state since the time the page was posted back to the server.(Inherited from Parameter.)
	SetDirty()	Marks the Parameter object so its state will be recorded in view state.(Inherited from Parameter.)
	ToString()	Converts the value of this instance to its equivalent string representation.(Inherited from Parameter.)
	TrackViewState()	Causes the Parameter object to track changes to its view state so they can be stored in the control's ViewState object and persisted across requests for the same page.(Inherited from Parameter.)

Explicit Interface Implementations

	Name	Description
	ICloneable.Clone()	Returns a duplicate of the current Parameter instance.(Inherited from Parameter.)
	IStateManager.LoadViewState(Object)	This API supports the product infrastructure and is not intended to be used directly from your code. Restores the data source view's previously saved view state.(Inherited from Parameter.)
	IStateManager.SaveViewState()	This API supports the product infrastructure and is not intended to be used directly from your code. Saves the changes to the Parameter object's view state since the time the page was posted back to the server.(Inherited from Parameter.)
	IStateManager.TrackViewState()	This API supports the product infrastructure and is not intended to be used directly from your code. Causes the Parameter object to track changes to its view state so they can be stored in the control's ViewState object and persisted across requests for the same page.(Inherited from Parameter.)
	IStateManager.IsTrackingViewState	This API supports the product infrastructure and is not intended to be used directly from your code. Gets a value indicating whether the Parameter object is saving changes to its view state.(Inherited from Parameter.)

A SessionParameter object is typically used in order to include the value of an HttpSessionState variable in the Where clause of a database query. The SessionField property identifies the session variable from which the SessionParameter retrieves a value.

Note
Controls that bind data to a parameter by using a SessionParameter object might throw an exception if the specified session variable is not set. To avoid this error (where appropriate), set the DefaultValue property.

Examples

The following example shows how to use a SessionParameter object. The example assumes that another page has stored an employee ID value in a session variable named empid. The example page uses the empid session variable in the Where clause of a query and displays the result of the query in a GridView control. Because the DefaultValue property of the SessionParameter object is set to 5, data for the record that has the employeeID value of 5 will still be displayed if no session variable named empid is set before you run the example.

No code example is currently available or this language may not be supported.

Version Information

.NET Framework
Available since 2.0

Thread Safety

Any public static ( Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.