Question

imagine I got an entity:

MyEntity
{
...
Nullable<Int64> MyProperty
...
}

I would like to do something like this:

Ctx.MyEntity.Where(x=>x.MyProperty/16 == 10) 

with Linq.Expression

So I create a parameter:

var param = Expression.parameter(typeOf(MyEntity));

Then the property:

var prop = Expression.PropertyOrField(param,"MyProperty");

If I would like to compare to 10 I would have done something like this:

var cmp = Expression.equal(prop,Expression.constant(10,prop.Type));

But first I need to divide prop by 16.

So I try:

var div = Expression.Divide(prop,Expression.constant(16, prop.type);

And this throw an exception of unmatching type.

Can someone help ?

Thx,

Answer 1

You need to create division expression like this:

Expression.Divide(prop, Expression.Constant((Nullable<Int64>)16, prop.Type))

It is necessary to explicitly convert 16 to type of the property, since when used as a literal, it is of type Int32, which is obviously not same as Nullable<Int64>.