public static Expression <Func <T, bool> > CombineBinary <T, R>(this Expression <Func <T, R> > self, Expression <Func <T, R> > expression, Func <Expression, Expression, BinaryExpression> combinator, ParameterExpression[] parameters = null)
where T : class
{
if (self == null)
{
throw new ArgumentNullException(nameof(self));
}
if (expression == null)
{
throw new ArgumentNullException(nameof(expression));
}
if (combinator == null)
{
throw new ArgumentNullException(nameof(combinator));
}
if (parameters == null)
{
// parameters can be on different levels of hierarchy so we should choose higher level parameter as a target for cloning
parameters = self.Parameters.First().Type.IsAssignableFrom(expression.Parameters.First().Type) ? expression.CloneParameters() : self.CloneParameters();
}
self = self.Update(self.RebindBodyParametersWith(parameters), parameters);
expression = expression.Update(expression.RebindBodyParametersWith(parameters), parameters);
var combined = combinator(self.Body, expression.Body);
return(Expression.Lambda <Func <T, bool> >(combined, parameters));
}
public static Expression <T> ApplyUnary <T>(this Expression <T> self, Func <Expression, Expression> unaryExpr)
where T : class
{
if (self == null)
{
return(null);
}
if (unaryExpr == null)
{
throw new ArgumentNullException(nameof(unaryExpr));
}
var parameters = self.CloneParameters();
self = self.Update(self.RebindBodyParametersWith(parameters), parameters);
return(Expression.Lambda <T>(unaryExpr(self.Body), parameters));
}