protected override Expression GetValueExpression(MapperContext context)
{
return(context.SourceInstance);
}
protected override Expression GetValueExpression(MapperContext context)
{
return(Expression.Convert(Expression.Convert(
context.SourceInstance, typeof(int)), context.TargetInstance.Type));
}
protected override Expression GetValueExpression(MapperContext context)
{
if (context.SourceInstance.Type == context.TargetInstance.Type)
{
return(context.SourceInstance);
}
if (context.SourceInstance.Type.IsNullable() && context.TargetInstance.Type.IsNullable())
{
var sourceUnderlyingType = Nullable.GetUnderlyingType(context.SourceInstance.Type);
var targetUnderlyingType = Nullable.GetUnderlyingType(context.TargetInstance.Type);
//It is forbidden to use nameof with unbound generic types. We use 'int' just to get around that.
var nullableValueAccess = Expression.MakeMemberAccess(context.SourceInstance,
context.SourceInstance.Type.GetProperty(nameof(Nullable <int> .Value)));
var convert = MapperConfiguration[sourceUnderlyingType, targetUnderlyingType].MappingExpression;
var constructor = context.TargetInstance.Type.GetConstructor(new Type[] { targetUnderlyingType });
var newNullable = Expression.New(constructor, Expression.Invoke(convert, nullableValueAccess));
return(Expression.Block
(
new[] { context.TargetInstance },
Expression.IfThenElse
(
Expression.Equal(context.SourceInstance, Expression.Constant(null, context.SourceInstance.Type)),
Expression.Assign(context.TargetInstance, Expression.Default(context.TargetInstance.Type)),
Expression.Assign(context.TargetInstance, newNullable)
),
context.TargetInstance
));
}
if (context.SourceInstance.Type.IsNullable() && !context.TargetInstance.Type.IsNullable())
{
//It is forbidden to use nameof with unbound generic types. We use 'int' just to get around that.
var nullableValueAccess = Expression.MakeMemberAccess(context.SourceInstance,
context.SourceInstance.Type.GetProperty(nameof(Nullable <int> .Value)));
var sourceUnderlyingType = context.SourceInstance.Type.GetUnderlyingTypeIfNullable();
if (sourceUnderlyingType == context.TargetInstance.Type)
{
return(Expression.Block
(
new[] { context.TargetInstance },
Expression.IfThenElse
(
Expression.Equal(context.SourceInstance, Expression.Constant(null, context.SourceInstance.Type)),
Expression.Assign(context.TargetInstance, Expression.Default(context.TargetInstance.Type)),
Expression.Assign(context.TargetInstance, nullableValueAccess)
),
context.TargetInstance
));
}
if (sourceUnderlyingType.IsImplicitlyConvertibleTo(context.TargetInstance.Type) ||
sourceUnderlyingType.IsExplicitlyConvertibleTo(context.TargetInstance.Type))
{
return(Expression.Block
(
new[] { context.TargetInstance },
Expression.IfThenElse
(
Expression.Equal(context.SourceInstance, Expression.Constant(null, context.SourceInstance.Type)),
Expression.Assign(context.TargetInstance, Expression.Default(context.TargetInstance.Type)),
Expression.Assign(context.TargetInstance, Expression.Convert(nullableValueAccess, context.TargetInstance.Type))
),
context.TargetInstance
));
}
var convertMethod = typeof(Convert).GetMethod($"To{context.TargetInstance.Type.Name}", new[] { context.SourceInstance.Type });
return(Expression.Block
(
new[] { context.TargetInstance },
Expression.IfThenElse
(
Expression.Equal(context.SourceInstance, Expression.Constant(null, context.SourceInstance.Type)),
Expression.Assign(context.TargetInstance, Expression.Default(context.TargetInstance.Type)),
Expression.Assign(context.TargetInstance, Expression.Call(convertMethod, nullableValueAccess))
),
context.TargetInstance
));
}
if (!context.SourceInstance.Type.IsNullable() && context.TargetInstance.Type.IsNullable())
{
var targetUnderlyingType = context.TargetInstance.Type.GetUnderlyingTypeIfNullable();
if (context.SourceInstance.Type.IsImplicitlyConvertibleTo(targetUnderlyingType) ||
context.SourceInstance.Type.IsExplicitlyConvertibleTo(targetUnderlyingType))
{
var constructor = context.TargetInstance.Type.GetConstructor(new Type[] { targetUnderlyingType });
return(Expression.New(constructor, Expression.Convert(context.SourceInstance, targetUnderlyingType)));
}
else
{
var constructor = context.TargetInstance.Type.GetConstructor(new Type[] { context.SourceInstance.Type });
return(Expression.New(constructor, context.SourceInstance));
}
}
throw new Exception($"Cannot handle {context.SourceInstance} -> {context.TargetInstance}");
}
protected abstract Expression GetValueExpression(MapperContext context);
protected virtual bool GetIsCreateNewInstance(MapperContext context)
{
return(context.Options.ReferenceBehavior == ReferenceBehaviors.CREATE_NEW_INSTANCE);
}
