Working with values from component (IDictionary<string, object>) not possible

[heikar]

Hi,

if i try to work with the returned value(s) in a component (IDictionary<string, object>) then an error appears.

Query:

query.SelectList(list => list
.Select(…)
.Select(x => ((int)x.Values["Prop1"])).WithAlias(() => alias.Prop1));

or
query.Where(x => ((int)x.Values["Prop1"]) > 100);

Error-Message:
ArgumentException: The Object with The Type "NHibernate.Util.DynamicComponent" cannot be convertet to the Type "System.Int32".

Many Greetings
heikar

[fredericDelaporte]

May you please provide a minimal but complete example demonstrating the issue? It implies supplying mappings, entity classes and compilable code.
If this does not appears to be a bug or missing feature in NHibernate, please ask for help on user group or StackOverflow instead. See here.

[heikar]

Hi @fredericDelaporte and @hazzik

In https://gist.github.com/heikar/ab992ca28ef92548f6dbd3d3644abb18 i have a test entity and the corresponding mapping.

I can query the table without problems.

But i cannot use the "dynamic fields" in the where clause. It throws an exception:

var items = session.QueryOver<Article>().Where(x => x.Attributes["Prop1"] == "...");

NHibernate.QueryException: "Type mismatch in NHibernate.Criterion.SimpleExpression: Attributes expected type NHibernate.Util.DynamicComponent, actual type System.String"

I hope, the code in the gist is helpful.

[heikar]

Hi @fredericDelaporte and @hazzik

there is news about this?

I think, the behavior is similar to #79 but instead of Linq is it here QueryOver.

[fredericDelaporte]

I had not spotted that.
QueryOver is not Linq as you likely know, and it is also a lot more limited about Lambda expression usages. Lambda in QueryOver are only meant to supply plain .Net class properties from which to extract the name that would be used for the underlying Criteria.

It cannot support a property pointed through Attributes["Prop1"]. It is not meant for this.

[heikar]

Hi @fredericDelaporte thanks for the answer.

This does not sound good for me. I have to use QueryOver and a lot of the entities have this DynamicComponent with dictionary.
The other use (load, save and delete) works perfect.

If i understand it right, then NHibernate try to resolve the property for Attributes["Prop1"] and cannot find it because it is not a property?

Do you think that it is possible to create a workaround for this task?

[fredericDelaporte]

It should be possible to use a criteria restriction, with the property name. But I am not a user of QueryOver and I cannot give you much guidance about using a Criteria restriction with QueryOver.

[heikar]

Hi @fredericDelaporte ,

i have created a solution that works for me, so the DynamicComponent is accessible in the Select/SelectList and Where.

I have made changes to the function FindMemberExpression in ExpressionProcessor.cs.

If an expression with the type ExpressionType.Call is given, i make a case distinction:

• Has the expression a DynamicComponent (IDictionary) and it is in the root entity
• Has the expression a DynamicComponent (IDictionary) and it is not in the root entity (JOIN)
• The expression is a "standard" property

But i am not deep enough in the topic "NHibernate Contributing", so i have created the gist and not a pull request.
I would be happy if someone could do a review :)