列表项目位置未在滚动时更新

Question

我似乎无法找到匹配的响应，但我正在尝试测试我的界面，除了当我实现滚轮时，它仍然完美无缺。选择时，可拖动标签会自动将其自身附加到列表项的位置。滚轮移动时，附带的标签随之移动。但是，要使用的附加标签的所选项目坐标更新存在延迟。我尝试了其他可以像按钮一样触发即时位置的事件，但无济于事。可能有人有想法作为一种解决方法吗？

using System;
using System.Drawing;
using System.Windows.Forms;

namespace matchMoving
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            label1.MouseDown += new MouseEventHandler(Label_Mouse_Down);
            label1.MouseMove += new MouseEventHandler(Label_Mouse_Move);
            listBox1.MouseWheel += new MouseEventHandler(List_Mouse_Scroll);
            listBox1.MouseMove += new MouseEventHandler(List_Mouse_Move);
            listBox1.MouseDown += new MouseEventHandler(List_Mouse_Down);
        }

        Rectangle IndexLocation;
        private Point MouseDownLocation;

        public void List_Function()
            {
                label1.Text = listBox1.SelectedIndex.ToString();
                IndexLocation = listBox1.GetItemRectangle(listBox1.SelectedIndex);
                int nx = Convert.ToInt32(IndexLocation.X);
                int ny = Convert.ToInt32(IndexLocation.Y);
                label1.Location = new Point(nx, ny);
                textBox1.Text = listBox1.GetItemRectangle(listBox1.SelectedIndex).ToString();
            }

        public void List_Mouse_Move(object sender, MouseEventArgs e)
        {
            if (MouseButtons == MouseButtons.Left)
            {
                List_Function();
            }
        }

        public void List_Mouse_Scroll(object sender, MouseEventArgs e)
        {
                List_Function();
        }

        private void List_Mouse_Down(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                List_Function();
            }
        }

        private void Label_Mouse_Down(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                MouseDownLocation = e.Location;
            }
        }

        private void Label_Mouse_Move(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                Point start = Point.Empty;
                int nx = Math.Min(Math.Max(label1.Left - MouseDownLocation.X + (e.X - start.X), 0), label1.Parent.Width - label1.Width);
                int ny = Math.Min(Math.Max(label1.Top - MouseDownLocation.Y + (e.Y - start.Y), 0), label1.Parent.Height - label1.Height);
                label1.Location = new Point(nx, ny);
            }
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            for (int x = 0; x < 40; x++)
            {
                listBox1.Items.Add("This is new text");
            }

        }
    }
}

Answer 1

这是我发现了什么可行的。此代码将创建一个标签，显示每个列表框项的索引。这个标签是可拖动的。选择列表框项目后，标签将附加到列表框项目的位置。滚动滚轮或鼠标选择新的列表框项目时，标签将跟随列表框项目的位置。要实现点击可控滚动，可能必须自定义？

using System;
using System.Drawing;
using System.Windows.Forms;
using System.Threading;
using System.ComponentModel;

namespace MouseMatchMoving
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            // These are the event handling functions
            label1.MouseDown += new MouseEventHandler(Label_Mouse_Down);
            label1.MouseMove += new MouseEventHandler(Label_Mouse_Move);
            label1.MouseUp += new MouseEventHandler(Label_Mouse_Up);
            listBox1.MouseWheel += new MouseEventHandler(List_Mouse_Scroll);
            listBox1.MouseMove += new MouseEventHandler(List_Mouse_Move);
            listBox1.MouseDown += new MouseEventHandler(List_Mouse_Down);
            backgroundWorker1.ProgressChanged += new ProgressChangedEventHandler(BProgress);
            backgroundWorker1.DoWork += new DoWorkEventHandler(BDowork);
            backgroundWorker1.RunWorkerCompleted += new RunWorkerCompletedEventHandler(BWCompleted);
            backgroundWorker1.WorkerReportsProgress = true;
            // Start the backgroundworker
            backgroundWorker1.RunWorkerAsync();
            label1.BringToFront();
        }

        Rectangle IndexLocation;
        private Point MouseDownLocation;

        // Form loading
        private void Form1_Load(object sender, EventArgs e)
        {
            for (int x = 0; x < 40; x++)
            {
                listBox1.Items.Add("This is new text");
            }
            listBox1.SelectedIndex = 0;
        }

        // This backgroundworker invokes the GUI thread
        private void BDowork(object sender, DoWorkEventArgs e)
        {
            if (InvokeRequired)
            {
                this.Invoke(new Action(() => List_Function()));
                return;
            }
        }

        private void BProgress(object sender, ProgressChangedEventArgs e)
        {
            label1.Text = e.ProgressPercentage.ToString();
            Console.WriteLine(e.ProgressPercentage.ToString());
            Console.WriteLine(e.UserState);
        }

        private void BWCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            Console.WriteLine(e.Cancelled);
        }

        // This begins the mouse ListBox Focus functions
        private void List_Mouse_Down(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                List_Function();
            }
        }

        public void List_Mouse_Move(object sender, MouseEventArgs e)
        {
            if (MouseButtons == MouseButtons.Left)
            {
                List_Function();
            }
        }

        // This is the mouse scrolling function which calls the backgroundworker
        public void List_Mouse_Scroll(object sender, MouseEventArgs e)
        {
            listBox1.SetSelected(listBox1.SelectedIndex, true);
            listBox1.GetSelected(listBox1.SelectedIndex);
            backgroundWorker1.RunWorkerAsync();
        }

        // This is invokes the draggable label mouse functions
        private void Label_Mouse_Down(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                MouseDownLocation = e.Location;
            }
        }

        private void Label_Mouse_Move(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                Point start = Point.Empty;
                int nx = Math.Min(Math.Max(label1.Left - MouseDownLocation.X + (e.X - start.X), 0), label1.Parent.Width - label1.Width);
                int ny = Math.Min(Math.Max(label1.Top - MouseDownLocation.Y + (e.Y - start.Y), 0), label1.Parent.Height - label1.Height);
                label1.Location = new Point(nx, ny);
            }
        }

        private void Label_Mouse_Up(object sender, MouseEventArgs e)
        {
            MouseDownLocation = e.Location;
        }

        // This is the mouse list tracking function
        public void List_Function()
        {
            label1.Text = listBox1.SelectedIndex.ToString();
            IndexLocation = listBox1.GetItemRectangle(listBox1.SelectedIndex);
            int nx = Convert.ToInt32(IndexLocation.X);
            int ny = Convert.ToInt32(IndexLocation.Y);
            label1.Location = new Point(nx, ny);
            textBox1.Text = listBox1.GetItemRectangle(listBox1.SelectedIndex).ToString();
            Console.WriteLine(listBox1.GetItemRectangle(listBox1.SelectedIndex));
        }
    }
}