Am I Doin This Right? SELECT / ExecuteNonQuery Statement

I am working on a web service method that will return weather or not a page url is stored in the database but the  ExecuteNonQuery keeps returning -1. I was just wondering if i was doing anything wrong or why the ExecuteNonQuery method does not return a value of 1 or more indicating that the pageurl exists in the database? I have tried using the SQLDataReader as well to no effect and I have verified that SELECT statement refers to valid table and field names. Any help or pointers would be appreciated. I'm still kind of a newb when it comes to db programming.

 1 <WebMethod()> _
2 Public Function IsPageStored(ByVal pageurl As String) As Boolean
3 If String.IsNullOrEmpty(pageurl) Then Return False
4
5 Dim conn As New SqlConnection()
6 conn.ConnectionString = ConfigurationManager.ConnectionStrings("dbStoredList").ConnectionString
7
8 Dim cmd As String
9 cmd = "SELECT [" & Constants.SourceFieldName & "] "
10 cmd &= "FROM [" & Constants.StoredCopyTableName & "] "
11 cmd &= "WHERE ([" & Constants.SourceFieldName & "] = '@Source')"
12 Dim C As New SqlCommand(cmd, conn)
13 C.Parameters.AddWithValue("@Source", New SqlTypes.SqlString(pageurl))
14 C.Parameters.Item("@Source").CompareInfo = SqlTypes.SqlCompareOptions.IgnoreCase
15
16 conn.Open()
17
18 Dim exists As Boolean = False
19 exists = (C.ExecuteNonQuery > 0)
20
21 conn.Close()
22 C.Dispose()
23 C = Nothing
24 conn.Dispose()
25 conn = Nothing
26
27 Return exists
28 End Function
29