I am using Lightspeed 4.0.1600.21511 (nightly 26 sept 2012) on the Northwind database. I try to group on the boolean Products.Discontinued field:
dataGridView1.DataSource = unitOfWork.Products
.GroupBy(p => p.Discontinued)
.Select(g =>
new {
g.Key,
Count = g.Count(),
})
.ToList();
This gives the following exception:
System.NullReferenceException was unhandled
Message=Object reference not set to an instance of an object.
Source=Mindscape.LightSpeed.Linq
StackTrace:
at Mindscape.LightSpeed.Linq.Plan.LinqQueryPlanExpression.<CreateRangeVariable>d__0.MoveNext()
at Mindscape.LightSpeed.Linq.CollectionUtils.AddRange[T](IList`1 list, IEnumerable`1 items)
at Mindscape.LightSpeed.Linq.Plan.LinqQueryPlanExpression.ExtractRangeVariablesFromNewExpression(NewExpression newbie, RangeVariableScope scope, IUnitOfWork unitOfWork)
at Mindscape.LightSpeed.Linq.Plan.LinqQueryPlanExpression.ExtractRangeVariables(Expression expression, RangeVariableScope scope, IUnitOfWork unitOfWork)
at Mindscape.LightSpeed.Linq.Plan.LinqQueryPlanExpression.ExtractRangeVariables(Expression expression, RangeVariableScope scope, IUnitOfWork unitOfWork)
at Mindscape.LightSpeed.Linq.Sqo.Select.Evaluate(ExpressionVisitor visitor, MethodCallExpression expression)
at Mindscape.LightSpeed.Linq.Plan.LinqQueryBuilder.VisitMethodCall(MethodCallExpression exp)
at Mindscape.LightSpeed.Linq.Plan.LinqQueryBuilder.Visit(Expression exp)
at Mindscape.LightSpeed.Linq.Plan.LinqQueryBuilder.Build(Expression translation, LinqQueryProvider provider)
at Mindscape.LightSpeed.Linq.LinqQueryProvider.GetExecutionPlan(Expression expression)
at Mindscape.LightSpeed.Linq.LinqQueryProvider.Execute(Expression expression)
at Mindscape.LightSpeed.Linq.LinqQueryProvider.System.Linq.IQueryProvider.Execute(Expression expression)
at Mindscape.LightSpeed.Linq.LinqQuery`1.GetEnumerator()
at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
at Northwind.Form1.button1_Click(Object sender, EventArgs e) in D:\Projects\Northwind\Northwind\Form1.cs:line 28
at System.Windows.Forms.Control.OnClick(EventArgs e)
at System.Windows.Forms.Button.OnClick(EventArgs e)
at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ButtonBase.WndProc(Message& m)
at System.Windows.Forms.Button.WndProc(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(IntPtr dwComponentID, Int32 reason, Int32 pvLoopData)
at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
at System.Windows.Forms.Application.Run(Form mainForm)
at Northwind.Program.Main() in D:\Projects\Northwind\Northwind\Program.cs:line 18
at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean ignoreSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart()
InnerException:
