Parameter.Direction Property

Reference

Definition

Namespace:: System.Web.UI.WebControls

Assembly:: System.Web.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.

Indicates whether the Parameter object is used to bind a value to a control, or the control can be used to change the value.

public:
 property System::Data::ParameterDirection Direction { System::Data::ParameterDirection get(); void set(System::Data::ParameterDirection value); };

public System.Data.ParameterDirection Direction { get; set; }

member this.Direction : System.Data.ParameterDirection with get, set

Public Property Direction As ParameterDirection

Property Value

ParameterDirection

One of the ParameterDirection values. Direction is set to Input by default.

Examples

The following code example demonstrates how to set the DefaultValue, Type, and Direction properties of Parameter objects when using them as output parameters and return value parameters with a stored procedure. This code example is part of a larger example provided for the SqlDataSourceStatusEventArgs class overview.

<asp:sqldatasource
    id="SqlDataSource1"
    runat="server"
    datasourcemode="DataSet"
    connectionstring="<%$ ConnectionStrings:MyNorthwind%>"
    selectcommand="getordertotal"
    onselected="OnSelectedHandler">
    <selectparameters>
      <asp:querystringparameter name="empId" querystringfield="empId" />
      <asp:parameter name="total" type="Int32" direction="Output" defaultvalue="0" />
      <asp:parameter name="_ret" type="Int32" direction="ReturnValue" defaultvalue="0" />
    </selectparameters>
</asp:sqldatasource>

<asp:sqldatasource
    id="SqlDataSource1"
    runat="server"
    datasourcemode="DataSet"
    connectionstring="<%$ ConnectionStrings:MyNorthwind%>"
    selectcommand="getordertotal"
    onselected="OnSelectedHandler">
    <selectparameters>
      <asp:querystringparameter name="empId" querystringfield="empId" />
      <asp:parameter name="total" type="Int32" direction="Output" defaultvalue="0" />
      <asp:parameter name="_ret" type="Int32" direction="ReturnValue" defaultvalue="0" />
    </selectparameters>
</asp:sqldatasource>

Remarks

The Direction property is currently not used by the Parameter class and is reserved for future use.

The Direction property describes the direction of the flow of data between the value that a Parameter instance is bound to and the Parameter object itself. The default value for the Direction property, Input, describes the most common scenario where the flow of data is always in one direction: from the value to which the Parameter object is bound to the Parameter object. Any changes made to the underlying value are reflected by the Parameter object, but any changes to the Parameter object are not reflected by the underlying data. You can set the Direction property to InputOutput or Output when working with output parameters, or ReturnValue when working with a return value from a stored procedure.

If the Direction property of the parameter is changed, the OnParameterChanged method is called.

Applies to

Поділитися через