更改列表框顺序反映XML后端文档中的更改

Question

Hey guys I am trying to change the order of items inside a listbox C# in a win form and then reflect the changes in the xml document. I am trying to do it with two buttons, Up and Down and it should move the selected list item up or down. When I try and move up or down I get this exception.

An unhandled exception of type 'System.ArgumentException' occurred in System.Windows.Forms.dll.  Additional information: Items collection cannot be modified when the DataSource property is set.

On this line: lstQuestsSorted.Items.Remove(selected);

    using System;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;
using System.Windows.Forms;
using System.Xml;
using System.Xml.Linq;

namespace WinQuestEditor
{
    public partial class Form1 : Form
    {
        private XDocument xDoc;
        private string path;
        public Form1()
        {
            InitializeComponent();
        }

        private void btnLoadProfile_Click(object sender, EventArgs e)
        {
            OpenFileDialog ofd = new OpenFileDialog();
            ofd.Filter = "XML| * .xml";
            if (ofd.ShowDialog() == DialogResult.OK)
            {
                path = ofd.FileName;
                xDoc = new XDocument();
                //xDoc.Load(path);
                xDoc = XDocument.Load(path);
                var listBoxItems = xDoc.Descendants("EasyQuest").Select(x => x.Element("Name").Value);
                lstQuestBox.DataSource = listBoxItems.ToList();

                var questsSorted = xDoc.Descendants("QuestsSorted").Descendants("QuestsSorted")
                    .Select(x => x.Attribute("Action").Value + " : " + x.Attribute("NameClass").Value);
                lstQuestsSorted.DataSource = questsSorted.ToList();

                var test = "";


            }


        }

        public void MoveUp()
        {
            MoveItem(-1);
        }

        public void MoveDown()
        {
            MoveItem(1);
        }

        public void MoveItem(int direction)
        {
            // Checking selected item
            if (lstQuestsSorted.SelectedItem == null || lstQuestsSorted.SelectedIndex < 0)
                return; // No selected item - nothing to do

            // Calculate new index using move direction
            int newIndex = lstQuestsSorted.SelectedIndex + direction;

            // Checking bounds of the range
            if (newIndex < 0 || newIndex >= lstQuestsSorted.Items.Count)
                return; // Index out of range - nothing to do

            object selected = lstQuestsSorted.SelectedItem;

            // Removing removable element
            lstQuestsSorted.Items.Remove(selected);
            // Insert it in new position
            lstQuestsSorted.Items.Insert(newIndex, selected);
            // Restore selection
            lstQuestsSorted.SetSelected(newIndex, true);
        }

        private void buttonUp_Click(object sender, EventArgs e)
        {
            MoveItem(-1);
        }

        private void buttonDown_Click(object sender, EventArgs e)
        {
            MoveItem(1);
        }

private void btnSave_Click(object sender, EventArgs e)
        {
            xDoc.Save(path);
            var something = "";
        }

    }
}

This is the XML in the background I want to change order with the list.

  <QuestsSorted>
<QuestsSorted Action="PickUp" NameClass="ExampleQuest1" />
<QuestsSorted Action="Pulse" NameClass="ExampleQuest1" />
<QuestsSorted Action="TurnIn" NameClass="ExampleQuest1" />
<QuestsSorted Action="PickUp" NameClass="ExampleQuest2" />
<QuestsSorted Action="Pulse" NameClass="ExampleQuest2" />
<QuestsSorted Action="TurnIn" NameClass="ExampleQuest2" />
<QuestsSorted Action="PickUp" NameClass="ExampleQuest3" />
<QuestsSorted Action="Pulse" NameClass="ExampleQuest3" />
<QuestsSorted Action="TurnIn" NameClass="ExampleQuest3" />
<QuestsSorted Action="PickUp" NameClass="ExampleQuest4" />
<QuestsSorted Action="Pulse" NameClass="ExampleQuest4" />
<QuestsSorted Action="TurnIn" NameClass="ExampleQuest4" />
<QuestsSorted Action="PickUp" NameClass="ExampleQuest5" />
<QuestsSorted Action="Pulse" NameClass="ExampleQuest5" />
<QuestsSorted Action="TurnIn" NameClass="ExampleQuest5" />
<QuestsSorted Action="PickUp" NameClass="ExampleQuest6" />
<QuestsSorted Action="Pulse" NameClass="ExampleQuest6" />
<QuestsSorted Action="TurnIn" NameClass="ExampleQuest6" />
<QuestsSorted Action="PickUp" NameClass="ExampleQuest7" />
<QuestsSorted Action="Pulse" NameClass="ExampleQuest7" />
<QuestsSorted Action="TurnIn" NameClass="ExampleQuest7" />
</QuestsSorted>

Answer 1

The problem is obvious, You can not change your listbox order when it is data bound. But you can instead of data bind the list box, add items one by one:

 var listBoxItems = xDoc.Descendants("EasyQuest").Select(x=>x.Element("Name").Value).ToList();

 foreach(var item in listBoxItems)
 {
     lstQuestsSorted.Items.add((string)item);
 }

Now you can change its order.

To save xml after change order:

private void btnSave_Click(object sender, EventArgs e)
    {
        XElement QuestsSorted = xDoc.Element("QuestsSorted");
        for (int i = 0; i < lstQuestsSorted.Items.Count; i++)
        {
            XElement qt = QuestsSorted.Elements().Skip(i).Take(1).FirstOrDefault();
            qt.Attribute("Action").Value = lstQuestsSorted.Items[i].ToString().Split(':')[0];
            qt.Attribute("NameClass").Value = lstQuestsSorted.Items[i].ToString().Split(':')[1];
        }
        xDoc.Save(path);
    }