public static Expression Create(FilterOperator filterOperator, Expression left, Expression right, Type propertyType)
{
switch (filterOperator)
{
case FilterOperator.IsEqualTo:
return(Expression.Equal(left, right));
case FilterOperator.IsNotEqualTo:
return(Expression.NotEqual(left, right));
case FilterOperator.IsContainedIn:
return(EnumerableExpressionFactory.IsContainedInExpression(left, right, propertyType));
case FilterOperator.IsNotContainedIn:
var isContainedIn = EnumerableExpressionFactory.IsContainedInExpression(left, right, propertyType);
return(Expression.Not(isContainedIn));
//Comparisons can't be applied to boolean
case FilterOperator.Contains:
case FilterOperator.DoesNotContain:
case FilterOperator.IsGreaterThan:
case FilterOperator.IsLessThan:
case FilterOperator.IsGreaterThanOrEqualTo:
case FilterOperator.IsLessThanOrEqualTo:
case FilterOperator.StartsWith:
case FilterOperator.EndsWith:
return(null);
default:
return(null);
}
}
public static Expression Create(FilterOperator filterOperator, Expression left, ConstantExpression right, Type propertyType)
{
var enumType = Enum.GetUnderlyingType(propertyType);
var convertExpression = Expression.Convert(left, enumType);
var convertValue = Expression.Convert(right, enumType);
switch (filterOperator)
{
case FilterOperator.IsEqualTo:
return(Expression.Equal(left, right));
case FilterOperator.IsNotEqualTo:
return(Expression.NotEqual(left, right));
case FilterOperator.IsGreaterThan:
return(Expression.GreaterThan(convertExpression, convertValue));
case FilterOperator.IsLessThan:
return(Expression.LessThan(convertExpression, convertValue));
case FilterOperator.IsGreaterThanOrEqualTo:
return(Expression.GreaterThanOrEqual(convertExpression, convertValue));
case FilterOperator.IsLessThanOrEqualTo:
return(Expression.LessThanOrEqual(convertExpression, convertValue));
case FilterOperator.IsContainedIn:
return(EnumerableExpressionFactory.IsContainedInExpression(left, right, propertyType));
case FilterOperator.IsNotContainedIn:
var isContainedIn = EnumerableExpressionFactory.IsContainedInExpression(left, right, propertyType);
return(Expression.Not(isContainedIn));
//Comparisons can't be applied to Enums
case FilterOperator.Contains:
case FilterOperator.DoesNotContain:
case FilterOperator.StartsWith:
case FilterOperator.EndsWith:
return(null);
default:
return(null);
}
}