PropertyExpression Class

Reference

Definition

Namespace:: System.Web.UI.WebControls.Expressions

Assembly:: System.Web.Extensions.dll

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Provides a way to create a Where clause from parameters in a WhereParameters collection.

public ref class PropertyExpression : System::Web::UI::WebControls::Expressions::ParameterDataSourceExpression

public class PropertyExpression : System.Web.UI.WebControls.Expressions.ParameterDataSourceExpression

type PropertyExpression = class
    inherit ParameterDataSourceExpression

Public Class PropertyExpression
Inherits ParameterDataSourceExpression

Inheritance: Object

DataSourceExpression

ParameterDataSourceExpression
PropertyExpression

Examples

The following example shows how to search the Products table of the AdventureWorks database for products whose MakeFlag property (a Boolean column) is set to true. The Boolean value parameter is set in a check box. The result of the query that is returned from the LinqDataSource control is displayed in a GridView control.

This code example is part of a larger example that is provided in Walkthrough: Filtering Data in a Web Page Using Declarative Syntax.

Remarks

The PropertyExpression class is used with the QueryExtender control to filter data in data fields. The PropertyExpression class compares a property value of a column to a specified value. For example, you can compare a Boolean value to the value in the discontinued column of a Products table in a database.

The PropertyExpression class creates an equals (==) comparison for the value of each parameter and the corresponding property of the IQueryable data object. If you provide more than one parameter, the parameters are combined using the logical AND operator. Parameters that contain an empty value are not added to the Where clause.

Constructors

PropertyExpression()

Initializes a new instance of the PropertyExpression class.

Properties

Context	Gets the HttpContext instance of the owner control. (Inherited from DataSourceExpression)
DataSource	Gets the data source object that is associated with the owner control. (Inherited from DataSourceExpression)
IsTrackingViewState	Gets a value that indicates whether a data source expression object is tracking its view state changes. (Inherited from DataSourceExpression)
Owner	Gets the owner control. (Inherited from DataSourceExpression)
Parameters	Gets the parameters that are associated with this DataSourceExpression object. (Inherited from ParameterDataSourceExpression)
ViewState	Gets an instance of the StateBag class that contains the current view state information. (Inherited from DataSourceExpression)

Methods

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)
GetQueryable(IQueryable)	Applies a PropertyExpression object by using the specified IQueryable data source object.
GetType()	Gets the Type of the current instance. (Inherited from Object)
LoadViewState(Object)	Loads the state of the values in the ParameterDataSourceExpression object that must be persisted. (Inherited from ParameterDataSourceExpression)
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
SaveViewState()	Saves the current view state of the ParameterDataSourceExpression object. (Inherited from ParameterDataSourceExpression)
SetContext(Control, HttpContext, IQueryableDataSource)	Executes the expression by using the specified owner control, context, and data source. (Inherited from ParameterDataSourceExpression)
SetDirty()	Marks the DataSourceExpression object so that its state will be saved in view state. (Inherited from DataSourceExpression)
ToString()	Returns a string that represents the current object. (Inherited from Object)
TrackViewState()	Tracks view-state changes of the ParameterDataSourceExpression object so that the changes can be stored in the StateBag object for the object. (Inherited from ParameterDataSourceExpression)

Explicit Interface Implementations

IStateManager.IsTrackingViewState	When implemented by a class, gets a value that indicates whether a data source expression object is tracking its view state changes. (Inherited from DataSourceExpression)
IStateManager.LoadViewState(Object)	When implemented by a class, loads the previously saved view state of the data source expression object. (Inherited from DataSourceExpression)
IStateManager.SaveViewState()	When implemented by a class, saves the current view state of the DataSourceExpression object. (Inherited from DataSourceExpression)
IStateManager.TrackViewState()	When implemented by a class, tracks view state changes of the DataSourceExpression object so that the changes can be stored in the StateBag object for the data source expression object. (Inherited from DataSourceExpression)

Applies to

共用方式為