列表項目位置沒有在滾動更新

Question

我似乎無法找到匹配的響應，但我試圖測試我的界面，它迄今爲止工作完美無瑕，除了當我實現滾輪。可拖動標籤自動附加到列表項目的位置，當它被選中時。當滾輪移動時，附帶的標籤隨之移動。但是，選定的項目座標更新會延遲所使用的附加標籤。我嘗試了其他可能觸發即時位置的事件，就像按鈕一樣，但無濟於事。可能任何人有一個想法作爲解決方法嗎？

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

這就是我發現什麼工作。此代碼將創建一個標籤，顯示每個列表框項目的索引。這個標籤是可拖動的。選擇列表框項目時，標籤將附加到列表框項目的位置。滾動滾動時或當鼠標選擇新的列表框項目時，該標籤將跟隨列表框項目的位置。實現一個可點擊控制的滾動可能必須是自定義的？

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)); 
     } 
    } 
}