SessionParameter Class

 

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

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

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

Public Class SessionParameter
	Inherits Parameter

NameDescription
System_CAPS_pubmethodSessionParameter()

Initializes a new unnamed instance of the SessionParameter class.

System_CAPS_protmethodSessionParameter(SessionParameter)

Initializes a new instance of the SessionParameter class with the values of the instance specified by the original parameter.

System_CAPS_pubmethodSessionParameter(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.

System_CAPS_pubmethodSessionParameter(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.

System_CAPS_pubmethodSessionParameter(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.

NameDescription
System_CAPS_pubpropertyConvertEmptyStringToNull

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.)

System_CAPS_pubpropertyDbType

Gets or sets the database type of the parameter.(Inherited from Parameter.)

System_CAPS_pubpropertyDefaultValue

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.)

System_CAPS_pubpropertyDirection

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.)

System_CAPS_protpropertyIsTrackingViewState

Gets a value indicating whether the Parameter object is saving changes to its view state.(Inherited from Parameter.)

System_CAPS_pubpropertyName

Gets or sets the name of the parameter.(Inherited from Parameter.)

System_CAPS_pubpropertySessionField

Gets or sets the name of the session variable that the parameter binds to.

System_CAPS_pubpropertySize

Gets or sets the size of the parameter.(Inherited from Parameter.)

System_CAPS_pubpropertyType

Gets or sets the type of the parameter.(Inherited from Parameter.)

System_CAPS_protpropertyViewState

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.)

NameDescription
System_CAPS_protmethodClone()

Returns a duplicate of the current SessionParameter instance.(Overrides Parameter.Clone().)

System_CAPS_pubmethodEquals(Object)

Determines whether the specified object is equal to the current object.(Inherited from Object.)

System_CAPS_protmethodEvaluate(HttpContext, Control)

Updates and returns the value of the SessionParameter object.(Overrides Parameter.Evaluate(HttpContext, Control).)

System_CAPS_protmethodFinalize()

Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.(Inherited from Object.)

System_CAPS_pubmethodGetDatabaseType()

Gets the DbType value that is equivalent to the CLR type of the current Parameter instance.(Inherited from Parameter.)

System_CAPS_pubmethodGetHashCode()

Serves as the default hash function. (Inherited from Object.)

System_CAPS_pubmethodGetType()

Gets the Type of the current instance.(Inherited from Object.)

System_CAPS_protmethodLoadViewState(Object)

Restores the data source view's previously saved view state.(Inherited from Parameter.)

System_CAPS_protmethodMemberwiseClone()

Creates a shallow copy of the current Object.(Inherited from Object.)

System_CAPS_protmethodOnParameterChanged()

Calls the OnParametersChanged method of the ParameterCollection collection that contains the Parameter object.(Inherited from Parameter.)

System_CAPS_protmethodSaveViewState()

Saves the changes to the Parameter object's view state since the time the page was posted back to the server.(Inherited from Parameter.)

System_CAPS_protmethodSetDirty()

Marks the Parameter object so its state will be recorded in view state.(Inherited from Parameter.)

System_CAPS_pubmethodToString()

Converts the value of this instance to its equivalent string representation.(Inherited from Parameter.)

System_CAPS_protmethodTrackViewState()

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.)

NameDescription
System_CAPS_pubinterfaceSystem_CAPS_privmethodICloneable.Clone()

Returns a duplicate of the current Parameter instance.(Inherited from Parameter.)

System_CAPS_pubinterfaceSystem_CAPS_privmethodIStateManager.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.)

System_CAPS_pubinterfaceSystem_CAPS_privmethodIStateManager.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.)

System_CAPS_pubinterfaceSystem_CAPS_privmethodIStateManager.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.)

System_CAPS_pubinterfaceSystem_CAPS_privpropertyIStateManager.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.

System_CAPS_noteNote

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.

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.

<%@ Page language="VB"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>ASP.NET Example</title>
</head>
<body>
    <form id="Form1" method="post" runat="server">
      <p>Show My Orders:</p>

      <asp:SqlDataSource
          id="OdbcDataSource1"
          runat="server"
          ProviderName="System.Data.Odbc"
          ConnectionString="dsn=MyOdbcDsn;"
          SelectCommand="SELECT OrderId, CustomerId, OrderDate 
                         FROM Orders 
                         WHERE EmployeeID = ? 
                         ORDER BY CustomerId ASC;">
          <SelectParameters>
              <asp:SessionParameter
                Name="empid"
                SessionField="empid"
                DefaultValue="5" />
          </SelectParameters>
      </asp:SqlDataSource>

      <p>
      <asp:GridView
          id="GridView1"
          runat="server"
          DataSourceID="OdbcDataSource1" />
      </p>
    </form>
  </body>
</html>

.NET Framework
Available since 2.0

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

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