Clever Geek Handbook

C # reflection lists: object does not match target type

Trying to add a class object to a list using reflection, but when calling the Add method with my class object as a parameter, I get "Object does not match target type"

Here's a code snippet (you can guess classString = "Processor"

)

PC fetched = new PC();

// Get the appropriate computer field to write to
FieldInfo field = fetched.GetType().GetField(classString);

// Prepare a container by making a new instance of the reffered class
// "CoreView" is the namespace of the program.
object classContainer = Activator.CreateInstance(Type.GetType("CoreView." + classString));

/*
    classContainer population code
*/

// This is where I get the error. I know that classContainer is definitely
// the correct type for the list it being added to at this point.
field.FieldType.GetMethod("Add").Invoke(fetched, new[] {classContainer});

Then this is part of the class, the above code adds classContainers to:

public class PC
{
    public List<Processor> Processor = new List<Processor>();
    public List<Motherboard> Motherboard = new List<Motherboard>();
    // Etc...
}
+3


source to share


2 answers


You are trying to call List.Add(Processor)

on PC

- you want to call it on the field value:

field.FieldType.GetMethod("Add").Invoke(field.GetValue(fetched),
                                        new[] {classContainer});


However, I would advise you not to post fields like this. Consider using properties instead.

+4


source


This method will add a new item to the whole list // just instead of using insert Add



        IList list = (IList)value;// this what you need to do convert ur parameter value to ilist

        if (value == null)
        {
            return;//or throw an excpetion
        }

        Type magicType = value.GetType().GetGenericArguments()[0];//Get class type of list
        ConstructorInfo magicConstructor = magicType.GetConstructor(Type.EmptyTypes);//Get constructor reference

        if (magicConstructor == null)
        {
            throw new InvalidOperationException(string.Format("Object {0} does not have a default constructor defined", magicType.Name.ToString()));
        }

        object magicClassObject = magicConstructor.Invoke(new object[] { });//Create new instance
        if (magicClassObject == null)
        {
            throw new ArgumentNullException(string.Format("Class {0} cannot be null.", magicType.Name.ToString()));
        }
        list.Insert(0, magicClassObject);
        list.Add(magicClassObject);
0


source






More articles:


All Articles