Assembly: System.Web (in System.Web.dll)
The property identifies the public property of the Control object identified by the ControlID property that the ControlParameter object binds to at run time. can be set to a simple string, such as "SelectedValue", or an expression using Eval syntax to identify complex control properties.
While the property is optional, typically both ControlID and properties are set for the Evaluate method to correctly bind to a control. If you set the ControlID property but not the property, the Evaluate method attempts to use the ControlValuePropertyAttribute attribute to identify a default property. (It is the responsibility of control authors to specify this attribute.) If this fails, Evaluate throws an ArgumentException exception.
The following table identifies which ASP.NET controls decorate properties with the ControlValuePropertyAttribute attribute.
The following code example demonstrates how to use a ControlParameter object to bind data displayed in a ListBox control to the selected value of a DropDownList control in a declarative scenario. The DropDownList control derives from the ListControl control. The ControlParameter object is added to the SelectParameters collection of the SqlDataSource control on the form, and corresponds to the "@Title" placeholder text in the SelectCommand property.
The following code example demonstrates how to set the ControlID and properties to identify the control that a ControlParameter object is bound to. The example populates a ListBox control with values. The SelectedValue property of the ListBox control is used to filter data retrieved by a SqlDataSource control and displayed by a GridView control.