Make the ctor static and you will not need the lock.
The CLR guarantees it will call the static ctor only once.
static ReportProviderSql()
{
_reportFunctions = new
Dictionary<Type,Func<ReportCriteria,IList<ReportType>>>();
_reportFunctions.Add(typeof(DetailByDateReportType), GetDetailByDate);
}
// Ryan
On Dec 14, 2007 8:02 PM, Ron Young <[EMAIL PROTECTED]> wrote:
> Yes it does. I'll have to consider that.
>
> Here is what I'm essentially going for.
>
> // client side:
> List<Report> detailByDateReports =
> provider.GetReports<DetailByDateReport>(criteria);
> foreach (DetailByDateReport rpt in detailByDateReports)
> // do something
>
> // the provider class, data layer
> public class ReportProviderSql : IReportProvider
> {
> private static Dictionary<Type, Func<ReportCriteria,
> IList<ReportType>>> _reportFunctions = null;
> private static object _syncLock = new object();
> public ReportProviderSql()
> {
> if (_reportFunctions == null)
> {
> lock(_syncLock)
> {
> if (_reportFunctions == null)
> {
> _reportFunctions = new
> Dictionary<Type,Func<ReportCriteria,IList<ReportType>>>();
> _reportFunctions.Add(typeof(DetailByDateReportType),
> GetDetailByDate);
> }
> }
> }
> }
> #region IReportProvider Members
> public IList<T> GetReport<T>(ReportCriteria criteria) where T :
> ReportType
> {
> Type t = typeof(T);
> if (_reportFunctions.ContainsKey(t))
> {
> return _reportFunctions[t].Invoke(criteria) as IList<T>;
> }
> return null;
> }
> #endregion
> private static IList<ReportType> GetDetailByDate(ReportCriteria
> criteria)
> {
> List<ReportType> resultset = new List<ReportType>();
>
> ReportsDataContext db = new ReportsDataContext();
>
> var query = db.proc_RptDetailByDate(criteria.StartDate,
> criteria.EndDate, criteria.EmployeeID, criteria.ProjectID);
>
> foreach (var item in query)
> {
> DetailByDateReportType rpt = new DetailByDateReportType();
> rpt.Employee = item.Employee;
> rpt.Project = item.Project;
> rpt.Date = item.Date;
> rpt.Comments = item.Comments;
> rpt.Time = item.Time;
> rpt.Duration = item.Duration ?? 0.0M;
> resultset.Add(rpt);
> }
>
> db.Dispose();
>
> return resultset;
> }
> }
>
> ________________________________________
> From: Discussion of advanced .NET topics. [EMAIL PROTECTED] On Behalf Of Bob
> Provencher [EMAIL PROTECTED]
> Sent: Friday, December 14, 2007 12:58 PM
>
> To: [email protected]
> Subject: Re: [ADVANCED-DOTNET] Method that returns List<BaseClass>
>
> I think if someone puts a Report in your list, which it's type implies is
> allowed, your foreach will throw an invalid cast exception.
>
> -----Original Message-----
> From: Discussion of advanced .NET topics.
> [mailto:[EMAIL PROTECTED] On Behalf Of Ron Young
> Sent: Friday, December 14, 2007 1:46 PM
> To: [email protected]
> Subject: Re: [ADVANCED-DOTNET] Method that returns List<BaseClass>
>
> Indeed it does. Thank you.
>
> I was under the impression that if the method that returned derived reports
> ultimately returned a list of the base report, then the client would get the
> properties defined in the base report.
>
> But it's up to the client to determine what types of reports are in the
> list, so this works:
>
> // client-side
> List<Report> reports = provider.GetReports();
> foreach (ReportA item in reports)
> WL(item.MyName);
>
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