InvalidCastException when trying to use FreeText with a local variable as the language argument #13315
Comments
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In the original expression, the argument is a |
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Workaround: fixup the expression to replace references to a local variable with the value of that variable. static class Extensions
{
public static IQueryable<TSource> ReplaceLocalWithItsValue<TSource, TValue>(this IQueryable<TSource> source, Expression<Func<TValue>> localExpression, TValue value)
{
if (localExpression.Body is MemberExpression memberExpr && memberExpr.Expression is ConstantExpression constant)
{
var visitor = new MemberReplacementVisitor<TValue>(constant.Value, memberExpr.Member, value);
var newExpression = visitor.Visit(source.Expression);
return source.Provider.CreateQuery<TSource>(newExpression);
}
throw new ArgumentException("Invalid local expression");
}
private class MemberReplacementVisitor<TValue> : ExpressionVisitor
{
private readonly object _instance;
private readonly MemberInfo _member;
private readonly TValue _replacementValue;
public MemberReplacementVisitor(object instance, MemberInfo member, TValue replacementValue)
{
_instance = instance;
_member = member;
_replacementValue = replacementValue;
}
protected override Expression VisitMember(MemberExpression node)
{
if (node.Expression is ConstantExpression constant && Equals(constant.Value, _instance) && Equals(node.Member, _member))
return Expression.Constant(_replacementValue, typeof(TValue));
return base.VisitMember(node);
}
}
}Usage: int lcid = CultureInfo.CurrentCulture.LCID;
var results = await _dbContext.Items
.Where(i => EF.Functions.FreeText(m.Text, searchTerm, lcid))
.ReplaceLocalWithItsValue(() => lcid, lcid)
.ToListAsync(); |
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Triage: moving this to the backlog to look into a general way of allowing values like this to not be parameterized. @smitpatel to link related issue. |
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We need to decorate FreeText method's argument as NotParameterizedAttribute to avoid having a parameter there. |
To support non-literal value for the argument Fixes dotnet#13315
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@smitpatel I just sent a PR for this (#20308) |
smitpatel
added
the
closed-fixed
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@smitpatel @ajcvickers August 2022 - I'm getting this error, using this code, .net 3.0: My azure instances are in 3.1 - The workaround listed here wouldn't work for my scenario, as I'm converting a SQL stored procedure using this method.
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@shahzadq77 this issue was about the use of the FreeText function with a parameter, but the code above doesn't seem to use FreeText. Please open a new issue with a runnable code sample and the full exception details. |
When I try to use a local variable for the
languageargument of theFreeTextmethod, I get the following exception:Steps to reproduce
Using a literal instead of the
lcidvariable works fine.The problem seems to be on this line:
https://github.com/aspnet/EntityFrameworkCore/blob/7b11733e091e937ea6f616ecf56ebc6fcb11955f/src/EFCore.SqlServer/Query/ExpressionTranslators/Internal/SqlServerFreeTextMethodCallTranslator.cs#L66
The translator assumes the expression to be a
ConstantExpression, which means it can only work with a hard-coded literal value.Further technical details
EF Core version: 2.1.1
Database Provider: Microsoft.EntityFrameworkCore.SqlServer (2.1.1)
Operating system: Windows 10 v1803
IDE: VS2017 v15.8.1
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