StrataFrame Forum » StrataFrame Application Framework - V1 » WebForms (How do I?) » Collection was modified; enumeration operation may not execute.

Collection was modified; enumeration operation may not execute.

ChanKK — Mon, 30 May 2011 22:42:54 GMT

I hit error as subject, and Idea? As we can see from the stack trace, it happen within ParseChildControl recursive call randomly. Please advice. Urgent.

Handled At

		System.Web.UI.Page.HandleError
		System.Web.UI.Page.ProcessRequestMain
		System.Web.UI.Page.ProcessRequest
		System.Web.UI.Page.ProcessRequest
		System.Web.UI.Page.ProcessRequestWithNoAssert
		ASP page : /FlexEA/PayStatement/Forms/PaySlipReport.aspx
		ASP.paystatement_forms_payslipreport_aspx.ProcessRequest
		System.Web.HttpApplication+CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute
		System.Web.HttpApplication.ExecuteStep
		System.Web.HttpApplication+ApplicationStepManager.ResumeSteps
		System.Web.HttpApplication.ResumeSteps
		Request : /FlexEA/PayStatement/Forms/PaySlipReport.aspx
		System.Web.HttpRuntime.ProcessRequestInternal
		System.Web.HttpRuntime.ProcessRequestNoDemand
		System.Web.Hosting.ISAPIRuntime.ProcessRequest

RE: Collection was modified; enumeration operation may not execute.

ChanKK — Mon, 30 May 2011 22:42:54 GMT

My code in case

DataEntryBasePage.cs

protected override void OnPreLoad(EventArgs e)

{

//-- Vault Comments:

//-- SF use property name (BusinessLater derived type) as key

//-- when store BO instance to session. It meant difference page

//-- might use the same BO instance if they are defined with

//-- same property name in page. It has possiblity that BO data/state

//-- defined in page not compatible with others. Since we unable to

//-- override this behavour (private methods), workaround is to

//-- dispose BO instance at session before SF initialize BO.

//-------------------------------------------------

//-- Dispose BO instance in session which used in

//-- this page to avoid "conflict" with other page

//-------------------------------------------------

if (!this.Page.IsPostBack && !this.Page.IsCallback)

{

//this.RemoveUnusedBusinessObjectsFromSession();

this.RemoveBusinessObjectsInstanceFromSession();

}

base.OnPreLoad(e);

}

private void RemoveBusinessObjectsInstanceFromSession()

{

string businessObjectName = string.Empty;

BusinessLayer businessObject;

PropertyInfo[] propertyInfos = GetBusinessObjectInfosEx();

foreach (PropertyInfo propInfo in propertyInfos)

{

businessObjectName = propInfo.Name;

businessObject = SessionManager.Instance.Get<BusinessLayer>(businessObjectName);

if (businessObject != null)

{

businessObject.Dispose();

businessObject = null;

SessionManager.Instance.Set(businessObjectName, null);

}

		System.Web.UI.ControlCollection+ControlCollectionEnumerator.MoveNext
		MicroFour.StrataFrame.UI.Web.BasePage.ParseChildControl
		MicroFour.StrataFrame.UI.Web.BasePage.ParseChildControl
		MicroFour.StrataFrame.UI.Web.BasePage.ParseChildControl
		MicroFour.StrataFrame.UI.Web.BasePage.ParseChildControl
		MicroFour.StrataFrame.UI.Web.BasePage.GetListOfControls
		MicroFour.StrataFrame.UI.Web.BasePage.Page_PreLoad
		System.Web.UI.Page.OnPreLoad
		Vfs.Generic.UI.Web.Strataframe.Forms.DataEntryBasePage.OnPreLoad
		System.Web.UI.Page.ProcessRequestMain