How to assign OnActivityResult values to the Listv

I have a Listview and Click Events in the respective listItems and need to get result back from the click events and populate on the List.

My BaseAdapter class is

 public class RemnantListAdapter : BaseAdapter<InventorySlabs>
 {
    private PartialInventory context;
    private List<InventorySlabs> RemnantList;

    public RemnantListAdapter(PartialInventory partialInventory, List<InventorySlabs> remnantList)
    {
        this.context = partialInventory;
        this.RemnantList = remnantList;
    }

    public override InventorySlabs this[int position]
    {
        get
        {
            return RemnantList[position];
        }
    }

    public override int Count
    {
        get
        {
            return RemnantList.Count;
        }
    }

    public override long GetItemId(int position)
    {
        return position;
    }

    public override int ViewTypeCount
    {
        get
        {
            return Count;
        }
    }

    public override int GetItemViewType(int position)
    {
        return position;
    }

    private class remnantHolder : Object
    {
        public Button EditRemnant1;

        public TextView Remnant1 = null;
        public TextView Rem_StockNMaterial1 = null;
        public TextView Rem_Dimensions1 = null;
        public TextView Rem_Status1 = null;
    }

    public override View GetView(int position, View convertView, ViewGroup parent)
    {
        remnantHolder holder = null;

        if (convertView == null)
        {
            convertView = (convertView ?? context.LayoutInflater.Inflate(Resource.Layout.remnant_list, parent, false));

            holder = new remnantHolder();                
            holder.EditRemnant1 = convertView.FindViewById<Button>(Resource.Id.editRemnant1);              

            holder.Remnant1 = convertView.FindViewById<TextView>(Resource.Id.remnant1);
            holder.Rem_StockNMaterial1 = convertView.FindViewById<TextView>(Resource.Id.remnant_mtrl1);
            holder.Rem_Dimensions1 = convertView.FindViewById<TextView>(Resource.Id.remnant_dimens1);
            holder.Rem_Status1 = convertView.FindViewById<TextView>(Resource.Id.remnant_status1);

            try
            {
                InventorySlabs remnantModel = this.RemnantList[position];
                if (remnantModel != null)
                {
                    holder.Remnant1.Text = "#" + remnantModel.ExtSlabNo;
                    holder.Rem_StockNMaterial1.Text = remnantModel.SellName + "-" + remnantModel.Depth + "-" + remnantModel.Finish;
                    double sqft = (remnantModel.Width * remnantModel.Height) / 144;
                    holder.Rem_Dimensions1.Text = "(" + remnantModel.Width.ToString() + " * " + remnantModel.Height.ToString() + ")" + sqft.ToString("N2");
                    holder.Rem_Status1.Text = remnantModel.Status;

                    holder.EditRemnant1.Click += delegate (object sender, System.EventArgs args)
                    {
                        if (remnantModel != null)
                        {
                            Intent intent = new Intent(context, typeof(EditRemnant));
                            intent.PutExtra("OpenPopType", 2);
                            intent.PutExtra("SlabNo", remnantModel.ExtSlabNo);
                            context.StartActivityForResult(intent, 1);
                        }
                    };                      
                }
            }
            catch (Exception ex)
            {
                var method = System.Reflection.MethodBase.GetCurrentMethod();
                var methodName = method.Name;
                var className = method.ReflectedType.Name;

                MainActivity.SaveLogReport(className, methodName, ex);
            }

            convertView.Tag = holder;
        }
        else
        {
            holder = (remnantHolder)convertView.Tag;
        }
        return convertView;
    }

    public void ActivityResult(int requestCode, Result resultCode, Intent data)
    {
        switch (requestCode)
        {              
            case 1:
                if (data != null)
                {
                    try
                    {
                        string remSlab = data.GetStringExtra("extSlabNo");
                        if (remSlab != null)
                        {
                            remnantData.Width = double.Parse(data.GetStringExtra("remWidth"));
                            remnantData.Height = double.Parse(data.GetStringExtra("remHeight"));
                            double sqft = (remnantData.Width * remnantData.Height) / 144;

                            Rem_Dimensions.Text = "(" + remnantData.Width.ToString() + " * " + remnantData.Height.ToString() + ")" + sqft.ToString("N2");
                        }
                    }
                    catch (Exception ex)
                    {
                        var method = System.Reflection.MethodBase.GetCurrentMethod();
                        var methodName = method.Name;
                        var className = method.ReflectedType.Name;

                        MainActivity.SaveLogReport(className, methodName, ex);
                    }
                }
                break;
        }
    }
}

In my Main Activity

I am calling the Result as

protected override void OnActivityResult(int requestCode, Result resultCode, Intent data)
{
    remnantListAdapter.ActivityResult(requestCode, resultCode, data);            
}

After editing the details in Edit view of the ListItem and close the Popup, I am not knowing how to Pass the Values to the Holder to Update in Listview.

You could pass the positon to the new activity in the click event and pass it back with the result intent.

For example:

    holder.EditRemnant1.Click += delegate (object sender, System.EventArgs args)
    {
        if (remnantModel != null)
        {
            Intent intent = new Intent(context, typeof(EditRemnant));
            intent.PutExtra("OpenPopType", 2);
            intent.PutExtra("SlabNo", remnantModel.ExtSlabNo);
            intent.PutExtra("Position", position );
            context.StartActivityForResult(intent, 1);
        }
    };

And in the new activity:

    protected override void OnCreate(Bundle savedInstanceState)
    {
        Intent intent = Intent;
        var position =intent.GetIntExtra("Position", -1);
        base.OnCreate(savedInstanceState);
        Intent data = new Intent();
        String text = "extSlabNo";
        data.PutExtra("extSlabNo", text);
        data.PutExtra("remWidth", 10);
        data.PutExtra("remHeight", 20);
        data.PutExtra("Position", position);
        SetResult(Result.Ok, data);
    }

Then you could modify the data in the adapter according to the positon value:

    public void ActivityResult(int requestCode, Result resultCode, Intent data)
    {
        switch (requestCode)
        {
            case 1:
                if (data != null)
                {
                    try
                    {
                        string remSlab = data.GetStringExtra("extSlabNo");
                        int position = data.GetIntExtra("Position", -1);
                        if (remSlab != null && position >= 0)
                        {
                            RemnantList[position].Width = data.GetIntExtra("remWidth", -1);
                            RemnantList[position].Height = data.GetIntExtra("remHeight", -1);
                            NotifyDataSetChanged();
                        }
                    }
                    catch (Exception ex)
                    {
                        var method = System.Reflection.MethodBase.GetCurrentMethod();
                        var methodName = method.Name;
                        var className = method.ReflectedType.Name;
                        MainActivity.SaveLogReport(className, methodName, ex);
                    }
                }
                break;
        }

And reset the adapter in MainActivity OnActivityResult() method :

public class MainActivity : AppCompatActivity
{
    RemnantListAdapter remnantListAdapter;
    ListView listView;
    protected override void OnCreate(Bundle savedInstanceState)
    {
        base.OnCreate(savedInstanceState);
        SetContentView(Resource.Layout.activity_main);
        List<InventorySlabs> remnantList = new List<InventorySlabs>();
        for(var i = 0; i < 10; i++)
        {
            InventorySlabs inventorySlabs = new InventorySlabs();
            inventorySlabs.Depth = i.ToString();
            inventorySlabs.ExtSlabNo = i.ToString();
            inventorySlabs.Finish = "Finish" + i.ToString();
            inventorySlabs.Height = 200;
            inventorySlabs.SellName = "SellName" + i.ToString();
            inventorySlabs.Status = "Status" + i.ToString();
            inventorySlabs.Width = 400;
            remnantList.Add(inventorySlabs);
        }
        listView = FindViewById<ListView>(Resource.Id.listView1);
        remnantListAdapter = new RemnantListAdapter(this, remnantList);
        listView.Adapter = remnantListAdapter;
    }

    protected override void OnActivityResult(int requestCode, [GeneratedEnum] Result resultCode, Intent data)
    {
        remnantListAdapter.ActivityResult(requestCode, resultCode, data);
        listView.Adapter = remnantListAdapter;
    }      
}