Below is an exception I get when calling Count on an NhQueryable object. It
appears to be this line in the ExpressionParameterVisitor.cs class:
_parameters.Add(expression, new NamedParameter("p" + (_parameters.Count +
1), expression.Value, type));
This happens while trying to get the data to populate a Telerik MVC Grid.
The grid allows columns to be filtered by one or two strings. If no filter
is specified on the grid or if a filter is specified with only one string
then the code runs fine. It's when two strings are specified in a filter
(say, a "starts with" string and an "ends with" string), the NH error
occurs. The where part of the query is created by a call to Telerik code:
Expression<Func<T, bool>> where =
ExpressionBuilder.Expression<T>(command.FilterDescriptors);
The command parameter is passed into the AJAX method with the grid filter
stings, and Telerik's ExpressionBuilder parses it into an Expression.
Then essentially the app does this:
IQueryable<T> query = session.Query<T>();
if (where != null) query = query.Where(where);
int rowCount = query.Count();
and it's that Count that gives the error. With my limited understanding of
what is going on with the expression code, it looks correct to me. The left
and right parts of the parsed Boolean expression are:
((IIF((item != null), item.AccountName, null) ??
"").ToLower().StartsWith("abc".ToLower()) == True)
((IIF((item != null), item.AccountName, null) ??
"").ToLower().EndsWith("def".ToLower()) == True)
But somehow, when NH's VisitConstantExpression is called, the
_parametersDictionary already has the
ConstantExpression in it, hence the error message.
Thanks.
-glenn-
System.ArgumentException was unhandled by user code
Message=An item with the same key has already been added.
Source=mscorlib
StackTrace:
at System.ThrowHelper.ThrowArgumentException(ExceptionResource
resource)
at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue
value, Boolean add)
at System.Collections.Generic.Dictionary`2.Add(TKey key, TValue
value)
at
NHibernate.Linq.Visitors.ExpressionParameterVisitor.VisitConstantExpression(ConstantExpression
expression) in
d:\CSharp\NH\NH\nhibernate\src\NHibernate\Linq\Visitors\ExpressionParameterVisitor.cs:line
42
at
Remotion.Data.Linq.Parsing.ExpressionTreeVisitor.VisitExpression(Expression
expression) in :line 0
at
NHibernate.Linq.Visitors.NhExpressionTreeVisitor.VisitExpression(Expression
expression) in
d:\CSharp\NH\NH\nhibernate\src\NHibernate\Linq\Visitors\NhExpressionTreeVisitor.cs:line
32
at
Remotion.Data.Linq.Parsing.ExpressionTreeVisitor.VisitBinaryExpression(BinaryExpression
expression) in :line 0
at
Remotion.Data.Linq.Parsing.ExpressionTreeVisitor.VisitExpression(Expression
expression) in :line 0
at
NHibernate.Linq.Visitors.NhExpressionTreeVisitor.VisitExpression(Expression
expression) in
d:\CSharp\NH\NH\nhibernate\src\NHibernate\Linq\Visitors\NhExpressionTreeVisitor.cs:line
32
at
Remotion.Data.Linq.Parsing.ExpressionTreeVisitor.VisitMethodCallExpression(MethodCallExpression
expression) in :line 0
at
Remotion.Data.Linq.Parsing.ExpressionTreeVisitor.VisitExpression(Expression
expression) in :line 0
at
NHibernate.Linq.Visitors.NhExpressionTreeVisitor.VisitExpression(Expression
expression) in
d:\CSharp\NH\NH\nhibernate\src\NHibernate\Linq\Visitors\NhExpressionTreeVisitor.cs:line
32
at
Remotion.Data.Linq.Parsing.ExpressionTreeVisitor.VisitMethodCallExpression(MethodCallExpression
expression) in :line 0
at
Remotion.Data.Linq.Parsing.ExpressionTreeVisitor.VisitExpression(Expression
expression) in :line 0
at
NHibernate.Linq.Visitors.NhExpressionTreeVisitor.VisitExpression(Expression
expression) in
d:\CSharp\NH\NH\nhibernate\src\NHibernate\Linq\Visitors\NhExpressionTreeVisitor.cs:line
32
at
Remotion.Data.Linq.Parsing.ExpressionTreeVisitor.VisitBinaryExpression(BinaryExpression
expression) in :line 0
at
Remotion.Data.Linq.Parsing.ExpressionTreeVisitor.VisitExpression(Expression
expression) in :line 0
at
NHibernate.Linq.Visitors.NhExpressionTreeVisitor.VisitExpression(Expression
expression) in
d:\CSharp\NH\NH\nhibernate\src\NHibernate\Linq\Visitors\NhExpressionTreeVisitor.cs:line
32
at
Remotion.Data.Linq.Parsing.ExpressionTreeVisitor.VisitBinaryExpression(BinaryExpression
expression) in :line 0
at
Remotion.Data.Linq.Parsing.ExpressionTreeVisitor.VisitExpression(Expression
expression) in :line 0
at
NHibernate.Linq.Visitors.NhExpressionTreeVisitor.VisitExpression(Expression
expression) in
d:\CSharp\NH\NH\nhibernate\src\NHibernate\Linq\Visitors\NhExpressionTreeVisitor.cs:line
32
at
Remotion.Data.Linq.Parsing.ExpressionTreeVisitor.VisitLambdaExpression(LambdaExpression
expression) in :line 0
at
Remotion.Data.Linq.Parsing.ExpressionTreeVisitor.VisitExpression(Expression
expression) in :line 0
at
NHibernate.Linq.Visitors.NhExpressionTreeVisitor.VisitExpression(Expression
expression) in
d:\CSharp\NH\NH\nhibernate\src\NHibernate\Linq\Visitors\NhExpressionTreeVisitor.cs:line
32
at
Remotion.Data.Linq.Parsing.ExpressionTreeVisitor.VisitUnaryExpression(UnaryExpression
expression) in :line 0
at
Remotion.Data.Linq.Parsing.ExpressionTreeVisitor.VisitExpression(Expression
expression) in :line 0
at
NHibernate.Linq.Visitors.NhExpressionTreeVisitor.VisitExpression(Expression
expression) in
d:\CSharp\NH\NH\nhibernate\src\NHibernate\Linq\Visitors\NhExpressionTreeVisitor.cs:line
32
at
Remotion.Data.Linq.Parsing.ExpressionTreeVisitor.VisitAndConvert[T](T
expression, String methodName) in :line 0
at
Remotion.Data.Linq.Parsing.ExpressionTreeVisitor.<>c__DisplayClass6`1.<VisitAndConvert>b__5(T
expression) in :line 0
at
Remotion.Data.Linq.Parsing.ExpressionTreeVisitor.VisitList[T](ReadOnlyCollection`1
list, Func`2 visitMethod) in :line 0
at
Remotion.Data.Linq.Parsing.ExpressionTreeVisitor.VisitAndConvert[T](ReadOnlyCollection`1
expressions, String callerName) in :line 0
at
Remotion.Data.Linq.Parsing.ExpressionTreeVisitor.VisitMethodCallExpression(MethodCallExpression
expression) in :line 0
at
Remotion.Data.Linq.Parsing.ExpressionTreeVisitor.VisitExpression(Expression
expression) in :line 0
at
NHibernate.Linq.Visitors.NhExpressionTreeVisitor.VisitExpression(Expression
expression) in
d:\CSharp\NH\NH\nhibernate\src\NHibernate\Linq\Visitors\NhExpressionTreeVisitor.cs:line
32
at
Remotion.Data.Linq.Parsing.ExpressionTreeVisitor.VisitAndConvert[T](T
expression, String methodName) in :line 0
at
Remotion.Data.Linq.Parsing.ExpressionTreeVisitor.<>c__DisplayClass6`1.<VisitAndConvert>b__5(T
expression) in :line 0
at
Remotion.Data.Linq.Parsing.ExpressionTreeVisitor.VisitList[T](ReadOnlyCollection`1
list, Func`2 visitMethod) in :line 0
at
Remotion.Data.Linq.Parsing.ExpressionTreeVisitor.VisitAndConvert[T](ReadOnlyCollection`1
expressions, String callerName) in :line 0
at
Remotion.Data.Linq.Parsing.ExpressionTreeVisitor.VisitMethodCallExpression(MethodCallExpression
expression) in :line 0
at
Remotion.Data.Linq.Parsing.ExpressionTreeVisitor.VisitExpression(Expression
expression) in :line 0
at
NHibernate.Linq.Visitors.NhExpressionTreeVisitor.VisitExpression(Expression
expression) in
d:\CSharp\NH\NH\nhibernate\src\NHibernate\Linq\Visitors\NhExpressionTreeVisitor.cs:line
32
at
Remotion.Data.Linq.Parsing.ExpressionTreeVisitor.VisitAndConvert[T](T
expression, String methodName) in :line 0
at
Remotion.Data.Linq.Parsing.ExpressionTreeVisitor.<>c__DisplayClass6`1.<VisitAndConvert>b__5(T
expression) in :line 0
at
Remotion.Data.Linq.Parsing.ExpressionTreeVisitor.VisitList[T](ReadOnlyCollection`1
list, Func`2 visitMethod) in :line 0
at
Remotion.Data.Linq.Parsing.ExpressionTreeVisitor.VisitAndConvert[T](ReadOnlyCollection`1
expressions, String callerName) in :line 0
at
Remotion.Data.Linq.Parsing.ExpressionTreeVisitor.VisitMethodCallExpression(MethodCallExpression
expression) in :line 0
at
Remotion.Data.Linq.Parsing.ExpressionTreeVisitor.VisitExpression(Expression
expression) in :line 0
at
NHibernate.Linq.Visitors.NhExpressionTreeVisitor.VisitExpression(Expression
expression) in
d:\CSharp\NH\NH\nhibernate\src\NHibernate\Linq\Visitors\NhExpressionTreeVisitor.cs:line
32
at
NHibernate.Linq.Visitors.ExpressionParameterVisitor.Visit(Expression
expression) in
d:\CSharp\NH\NH\nhibernate\src\NHibernate\Linq\Visitors\ExpressionParameterVisitor.cs:line
20
at NHibernate.Linq.NhLinqExpression..ctor(Expression expression) in
d:\CSharp\NH\NH\nhibernate\src\NHibernate\Linq\NhLinqExpression.cs:line 37
at NHibernate.Linq.NhQueryProvider.PrepareQuery(Expression
expression, IQuery& query, NhLinqExpression& nhQuery) in
d:\CSharp\NH\NH\nhibernate\src\NHibernate\Linq\NhQueryProvider.cs:line 41
at NHibernate.Linq.NhQueryProvider.Execute(Expression expression) in
d:\CSharp\NH\NH\nhibernate\src\NHibernate\Linq\NhQueryProvider.cs:line 26
at NHibernate.Linq.NhQueryProvider.Execute[TResult](Expression
expression) in
d:\CSharp\NH\NH\nhibernate\src\NHibernate\Linq\NhQueryProvider.cs:line 103
at System.Linq.Queryable.Count[TSource](IQueryable`1 source)
at
Website.Services.LookupTableServiceBase`1.GetLookupGrid(GridCommand
command, IUserInfo`1 userInfo, String userNameMember) in
G:\Website\Services\LookupTableServiceBase.cs:line 169
at
Website.Controllers.LookupTablesController.LookupIndex[T](GridCommand
command, ILookupTableService`1 lookupService) in
G:\Website\Controllers\LookupTablesController.cs:line 81
at
Website.Controllers.LookupTablesController._NicknameIndex(GridCommand
command) in G:\Website\Controllers\LookupTablesController.cs:line 475
at lambda_method(Closure , ControllerBase , Object[] )
at System.Web.Mvc.ActionMethodDispatcher.Execute(ControllerBase
controller, Object[] parameters)
at
System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext
controllerContext, IDictionary`2 parameters)
at
System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext
controllerContext, ActionDescriptor actionDescriptor, IDictionary`2
parameters)
at
System.Web.Mvc.ControllerActionInvoker.<>c__DisplayClass15.<InvokeActionMethodWithFilters>b__12()
at
System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodFilter(IActionFilter
filter, ActionExecutingContext preContext, Func`1 continuation)
InnerException:
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