如何：使用采用参数的存储过程
LINQ to SQL 会将输出参数映射到引用参数，并且对于值类型，会将参数声明为可为空。
有关如何在返回行集的查询中使用输入参数的示例，请参阅如何返回行集。
示例 1
下面的示例带有单个输入参数（客户 ID）并返回一个输出参数（该客户的总销售额）。
CREATE PROCEDURE [dbo].[CustOrderTotal]
@CustomerID nchar(5),
@TotalSales money OUTPUT
AS
SELECT @TotalSales = SUM(OD.UNITPRICE*(1-OD.DISCOUNT) * OD.QUANTITY)
FROM ORDERS O, "ORDER DETAILS" OD
where O.CUSTOMERID = @CustomerID AND O.ORDERID = OD.ORDERID
[Function(Name="dbo.CustOrderTotal")]
[return: Parameter(DbType="Int")]
public int CustOrderTotal([Parameter(Name="CustomerID", DbType="NChar(5)")] string customerID, [Parameter(Name="TotalSales", DbType="Money")] ref System.Nullable<decimal> totalSales)
{
IExecuteResult result = this.ExecuteMethodCall(this, ((MethodInfo)(MethodInfo.GetCurrentMethod())), customerID, totalSales);
totalSales = ((System.Nullable<decimal>)(result.GetParameterValue(1)));
return ((int)(result.ReturnValue));
}
<FunctionAttribute(Name:="dbo.CustOrderTotal")> _
Public Function CustOrderTotal(<Parameter(Name:="CustomerID", DbType:="NChar(5)")> ByVal customerID As String, <Parameter(Name:="TotalSales", DbType:="Money")> ByRef totalSales As System.Nullable(Of Decimal)) As <Parameter(DbType:="Int")> Integer
Dim result As IExecuteResult = Me.ExecuteMethodCall(Me, CType(MethodInfo.GetCurrentMethod, MethodInfo), customerID, totalSales)
totalSales = CType(result.GetParameterValue(1), System.Nullable(Of Decimal))
Return CType(result.ReturnValue, Integer)
End Function
示例 2
您将按如下方式调用此存储过程：
Northwnd db = new Northwnd(@"c:\northwnd.mdf");
decimal? totalSales = 0;
db.CustOrderTotal("alfki", ref totalSales);
Console.WriteLine(totalSales);
Dim db As New Northwnd("C:\...\northwnd.mdf")
Dim totalSales As Decimal? = 0
db.CustOrderTotal("alfki", totalSales)
Console.WriteLine(totalSales)