How to Remove Specific Item from each Object in Generic List

Question

Background

I have a list of generic objects. Each generic object has a specific field I need to remove.

I create the list like this.

list = new List<Object>();
list = JsonConvert.DeserializeObject<List<T>>(OutJson, new BooleanJsonConverter());

However i need to then remove a item from every object in that list. However i don't know how many or what objects are in the list. I do know that there will always be a field that i need to remove however.

Pseudocode

I think I need to do something like this, but in a generic way.

    //Loop through list objects, and for each object, loop through its 
    //properties. If any of the properties match a string, remove 
    //that property from the object.  

                foreach (var object in list)
                {
                    foreach (var item in object)
                    {
                        if(item.ToUpper() == "SpecificKey")
                        {
                            list.Remove(item);

                        }
                    }

                }

Question

How do I loop through the generic object in a list and remove a specific item if it is present?

Your code makes no sense. What is `var object in list` and what is `var item in item`? — DavidG, Jun 23 '16 at 15:11
@DavidG, I've added a comment in the code to explain a little better what i'm trying to do. — Dan Cundy, Jun 23 '16 at 15:16
No it was pseudo code, iIve now marked it as such. Apologies. — Dan Cundy, Jun 23 '16 at 15:21
Loop through properties of generic object, removing specific item ftom list, all these questions been asked before... It is possible with reflection. Search in google or stackoverflow — M.kazem Akhgary, Jun 23 '16 at 15:23
Do you know about [`List.RemoveAll()`](https://msdn.microsoft.com/en-us/library/wdka673a.aspx)? — Hans Keﬆing, Jun 23 '16 at 15:24

score 1 · Accepted Answer · answered Jun 23 '16 at 15:26

1

I think to complete this, it's better to mark the objects as dynamic.

Then this would work.

List<dynamic> list = JsonConvert.DeserializeObject<List<T>>(OutJson, new BooleanJsonConverter());

list.RemoveAll(x=>x["SpecificKey"]!=null);

answered Jun 23 '16 at 15:26

MoustafaS

1,991
11
20

Not sure i can make them Dynamic. Can you explain what the Lambda is doing please? – Dan Cundy Jun 24 '16 at 07:35
If its dynamic, checking if object["Prop"] will return null if it doesnt have it, otherwise it will leave it as it is – MoustafaS Jun 24 '16 at 16:03

score 0 · Answer 2 · edited May 23 '17 at 12:22

I have a list of generic objects. Each generic object has a specific field I need to remove.

If you're trying to access a specific property on an objection, you can use reflection. See the answer here:

Get property value from string using reflection in C#

i need to then remove a item from every object in that list. However i don't know how many or what objects are in the list. I do know that there will always be a field that i need to remove however.

Your pseudocode is code is confusing, but it seems like you're just trying to remove a child from a parent object. If that is the case, and the child is a complex object, then set it equal to null.

If you mean to say that you need to any object from the list that contains a property that has the specified property name, then you should know that you cannot remove items from a list while iterating through it using foreach. See the answer here:

C# List - Removing items while looping / iterating

How to Remove Specific Item from each Object in Generic List

Background

Pseudocode

Question

2 Answers2