Assigning A Stored Procedure Return Value To A Control

Hi, I have an app where I am calling a stored procedure that runs and returns an integer.  I would like to assign this integer to a control on the page.  Here is a sample of code and below I will give the errors:
 Protected Sub NewButton_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles NewButton.Click

        Dim tempconnection As New Data.SqlClient.SqlConnection(ConfigurationManager.ConnectionStrings("TestConnectionString").ConnectionString)
        Dim tempproc As New Data.SqlClient.SqlCommand("SP_FetchProviders", tempconnection)
        Dim tempparam As New Data.SqlClient.SqlParameter

        tempproc.CommandType = Data.CommandType.StoredProcedure

        tempproc.Parameters.Add(New SqlParameter("@Agency_ID", Data.SqlDbType.Int))
        tempproc.Parameters("@Agency_ID").Value = "8" 'Using a number just to test, will be populated by a session variable later
        tempparam = tempproc.CreateParameter()
        tempparam.ParameterName = "@OutValue"
        tempparam.Direction = Data.ParameterDirection.ReturnValue
        tempparam.SqlDbType = Data.SqlDbType.Int
        tempconnection.Open()
        tempproc.ExecuteNonQuery()
        Dim labelfill As String
        labelfill = tempproc.Parameters("@OutValue").Value
        tempconnection.Close()

        CType(Me.DetailsView1.FindControl("OmbudINSDDL"), DropDownList).Items.Add(labelfill) 'This is inside of a detailsview templatefield
    End Sub
 
Here is the stored procedure
 
set ANSI_NULLS ON
set QUOTED_IDENTIFIER ON
go

ALTER  procedure [dbo].[SP_FetchProviders]
    @Agency_ID     int
as

    Select Name, ProviderSubUnit_ID
    From ProviderSubunit a join Ombudsman b on a.contractproviders_id=b.contractproviders_id

    Where b.agency_id = @Agency_ID
       
    Order by Name
 
This takes the @Agency_ID as input variable, and has returns an integer (according to SQL management studio).  When I try to run my code I get the error that an sqlparameter with parametername @OutValue is not contained by this sqlparametercollection.
 This may be a simple question, but does the outvalue have to be declared in the stored procedure?  If so, can you provide the right syntax?  If not, can you offer a suggestion to populate the dropdownlist with the returned value?  Thanks in advance.