Parameter.Direction Parameter.Direction Parameter.Direction Parameter.Direction Property

定義

表示此 Parameter 物件是否用來將值繫結至控制項,或是這個控制項是否可用來變更該值。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

屬性值

其中一個 ParameterDirection 值。One of the ParameterDirection values. 根據預設,Direction 是設為 InputDirection is set to Input by default.

範例

下列程式碼範例示範如何在使用預DefaultValue存程式做為輸出Parameter參數和傳回值參數時,設定物件的、 TypeDirection屬性。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. 這個程式碼範例是針對SqlDataSourceStatusEventArgs類別總覽提供之較大範例的一部分。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>

備註

屬性目前不會Parameter由類別使用,而且會保留供日後使用。 DirectionThe Direction property is currently not used by the Parameter class and is reserved for future use.

屬性會描述實例所Parameter系結之值與物件本身之間的資料流程方向。 Parameter DirectionThe 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. 屬性的預設ParameterParameter會描述最常見的情況,也就是資料的流程一律為單一方向:從物件系結至物件的值。 Input DirectionThe 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. 對基礎值所做的任何變更都會由Parameter物件反映,但對Parameter物件所做的任何變更都不會反映在基礎資料。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. 您可以在使用Direction輸出參數InputOutputOutput ,或ReturnValue在使用預存程式的傳回值時,將屬性設定為或。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.

如果參數的OnParameterChanged屬性已變更,則會呼叫方法。 DirectionIf the Direction property of the parameter is changed, the OnParameterChanged method is called.

適用於