EntityDataSource.WhereParameters Property

Reference

Definition

Namespace:: System.Web.UI.WebControls

Assembly:: System.Web.Entity.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.

Gets the collection of parameters that are used to create the WHERE clause.

public:
 property System::Web::UI::WebControls::ParameterCollection ^ WhereParameters { System::Web::UI::WebControls::ParameterCollection ^ get(); };

[System.ComponentModel.Browsable(false)]
[System.Web.UI.PersistenceMode(System.Web.UI.PersistenceMode.InnerProperty)]
public System.Web.UI.WebControls.ParameterCollection WhereParameters { get; }

[<System.ComponentModel.Browsable(false)>]
[<System.Web.UI.PersistenceMode(System.Web.UI.PersistenceMode.InnerProperty)>]
member this.WhereParameters : System.Web.UI.WebControls.ParameterCollection

Public ReadOnly Property WhereParameters As ParameterCollection

Property Value

ParameterCollection

The parameters that are used for creating the WHERE clause.

Implements

WhereParameters

Attributes: BrowsableAttribute PersistenceModeAttribute

Examples

The XML markup in the following example, in an .aspx file, retrieves a value from a control and passes it as a parameter to the Where property.

<asp:EntityDataSource ID="SalesOrderHeader" runat="server"
  ConnectionString="name=AdventureWorksEntities"
  DefaultContainerName="AdventureWorksEntities" EnableDelete="True"
  EnableInsert="True" EnableUpdate="True" EntitySetName="SalesOrderHeader"
  EntityTypeFilter="" OrderBy="it.TotalDue DESC" Select=""
   Where="it.OnlineOrderFlag = TRUE AND it.TotalDue > @ordercost">
  <WhereParameters>
    <asp:ControlParameter ControlID="costLimit" DbType="Int32"
      DefaultValue="2500" Name="ordercost" PropertyName="Text" />
  </WhereParameters>
</asp:EntityDataSource>

The previous XML example is the same as the following ObjectQuery<T> named onlineOrders:

ObjectQuery<SalesOrderHeader> onlineOrders =
      context.SalesOrderHeader
       .Where("it.OnlineOrderFlag = TRUE AND it.TotalDue > @ordercost",
         new ObjectParameter("ordercost", orderCost))
        .OrderBy("it.TotalDue DESC");

Remarks

Like the Where method of the ObjectQuery<T> class, parameters can be passed to the predicate assigned to the Where property. The WhereParameters property of the EntityDataSource control specifies a ParameterCollection that contains the parameters to supply to the WHERE clause of the query. The WhereParameters property uses named arguments to refer to the parameters that are specified in the string that is supplied to the Where property.

If the WhereParameters property is not set, no parameter substitution is made. All the parameter names in the WHERE clause preceded by the symbol "@" must have a matching name in the ParameterCollection. Null values are not allowed for parameters in a ParameterCollection.

Applies to

Zdieľať cez