Error message when you view an activity form in Microsoft Dynamics CRM 4.0: “Exception of type ‘System.Web.HttpUnhandledException’ was thrown”
Symptoms
When you view an activity form in Microsoft Dynamics CRM 4.0, you receive the following error message:
Error: Exception of type ‘System.Web.HttpUnhandledException’ was thrown.Error Message: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.Error Details: Exception of type ‘System.Web.HttpUnhandledException’ was thrown.Source File: Not availableLine Number: Not availableRequest URL: http://URL
Stack Trace Info: [ArgumentNullException: Key cannot be null.Parameter name: key]at System.Collections.Hashtable.ContainsKey(Object key)at System.Collections.Hashtable.Contains(Object key)at Microsoft.Crm.Metadata.PreloadedMetadataCacheDataProvider.TryGetEntity(String entityName, NameMappingType mapping)at Microsoft.Crm.Metadata.DynamicMetadataCache.GetEntity(String entityName, NameMappingType mapping)at Microsoft.Crm.Security.User.HasPrivilege(IUser user, String entityName, PrivilegeType privilegeType, PrivilegeDepth privilegeDepth)at Microsoft.Crm.Security.User.HasPrivilege(IUser user, String entityName, AccessRights accessRights, PrivilegeDepth privilegeDepth)at Microsoft.Crm.Security.User.HasPrivilege(IUser user, String entityName, AccessRights accessRights)at Microsoft.Crm.Application.Components.Sdk.FormControls.Web.LookupControl.set_LookupTypes(Int32[] value)at Microsoft.Crm.Application.Components.Sdk.FormControls.Web.LookupControl.set_Metadata(AttributeMetadata value)at Microsoft.Crm.Application.ControlActivator.CreateControl(ControlDescriptor controlDescriptor, String clientId)at Microsoft.Crm.Application.Forms.CrudForm.BuildFormModel(FormDescriptor formDescriptor)at Microsoft.Crm.Application.Forms.CustomizableForm.Execute(Entity entity, String formType)at Microsoft.Crm.Application.Forms.CustomizableForm.Execute(Entity entity)at Microsoft.Crm.Web.Activities.BasicActivityPage.ConfigureForm()at Microsoft.Crm.Web.Activities.PhoneCallDetailPage.ConfigureForm()at Microsoft.Crm.Application.Controls.AppUIPage.OnPreRender(EventArgs e)at System.Web.UI.Control.PreRenderRecursiveInternal()at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
Resolution
This problem occurs because the FormDescriptor object caches some entity metadata. Therefore,an ArgumentNullException exception occurs.