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Use Expression.Constant to allow Nullable comparison

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Using Expression.Constant for GetClosureOverConstant. Came to this solution from reading:  http://bradwilson.typepad.com/blog/2008/07/creating-nullab.html
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Matt Furden 2018-05-27 18:33:10 -07:00
parent 26d9b09bf7
commit cd561e9f3d
1 changed files with 7 additions and 6 deletions
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13
Sieve/Services/SieveProcessor.cs
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@ -142,7 +142,7 @@ namespace Sieve.Services
? converter.ConvertFrom(filterTerm.Value) ? converter.ConvertFrom(filterTerm.Value)
: Convert.ChangeType(filterTerm.Value, property.PropertyType); : Convert.ChangeType(filterTerm.Value, property.PropertyType);
Expression filterValue = GetClosureOverConstant(constantVal); Expression filterValue = GetClosureOverConstant(constantVal, property.PropertyType);
dynamic propertyValue = Expression.PropertyOrField(parameterExpression, property.Name); dynamic propertyValue = Expression.PropertyOrField(parameterExpression, property.Name);
@ -219,12 +219,13 @@ namespace Sieve.Services
} }
} }
//Workaround to ensure that the filter value gets passed as a parameter in generated SQL from EF Core // Workaround to ensure that the filter value gets passed as a parameter in generated SQL from EF Core
//See https://github.com/aspnet/EntityFrameworkCore/issues/3361 // See https://github.com/aspnet/EntityFrameworkCore/issues/3361
private Expression GetClosureOverConstant<T>(T constant) // Expression.Constant passed the target type to allow Nullable comparison
// See http://bradwilson.typepad.com/blog/2008/07/creating-nullab.html
private Expression GetClosureOverConstant<T>(T constant, Type targetType)
{ {
Expression<Func<T>> closure = () => constant; return Expression.Constant(constant, targetType);
return closure.Body;
} }
private IQueryable<TEntity> ApplySorting<TEntity>( private IQueryable<TEntity> ApplySorting<TEntity>(