Question

嘿伙计们我试图以win形式更改列表框C＃中项目的顺序，然后反映xml文档中的更改。我试图用两个按钮，向上和向下，它应该向上或向下移动选定的列表项。当我尝试向上或向下移动时，我得到了这个例外。

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.

在这一行：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 = "";
        }

    }
}

这是后台的XML，我想用列表更改顺序。

  <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

问题很明显，当数据绑定时，您无法更改列表框顺序。但是你可以代替数据绑定列表框，逐个添加项目：

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

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

现在你可以改变它的顺序。

在变更单后保存xml：

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);
    }

更改列表框顺序反映XML后端文档中的更改

1 个答案: