GetAssignmentFromBinding(MemberBinding binding,
ParameterExpression paramSourceExisting,
ParameterExpression paramSourceNew,
ParameterExpression paramDestination)
{
var existingAssignment = binding as MemberAssignment
?? throw new ArgumentException("Only binding of type MemberAssignment can be used. " +
$"Received binding of type {binding.BindingType}, {binding.ToString()}");
var targetMember = Expression.MakeMemberAccess(paramDestination, existingAssignment.Member);
var newExpression = new ParameterReplacerVisitor(paramSourceExisting, paramSourceNew)
.Visit(existingAssignment.Expression);
var assignment = Expression.Assign(targetMember, newExpression);
return(assignment);
}
public Expression <Func <TSource, TDestination> > CombineIntoMapperWithConstructor(
Expression <Func <TSource, TDestination> > recipientExpression,
Expression <Func <TSource, TDestination> > donorExpression)
{
var paramReplacer = new ParameterReplacerVisitor(
donorExpression.Parameters[0],
recipientExpression.Parameters[0]);
var donorWithCorrectedParam = (Expression <Func <TSource, TDestination> >)paramReplacer.Visit(donorExpression);
var visitor = new MemberInitBindingsCombinationVisitor <TSource, TDestination>()
{
recipientExpression = recipientExpression,
donorExpression = donorWithCorrectedParam
};
var combinedExpr = (Expression <Func <TSource, TDestination> >)visitor.Visit(recipientExpression);
return(combinedExpr);
}