已重写CreateParams的ListBox不会引发项事件

当我尝试此代码时,它工作得很好:

  public partial class Form1 : Form {
    MyListBox mList;
    public Form1() {
      InitializeComponent();
    }

    protected override void OnLoad(EventArgs e) {
      mList = new MyListBox(this);
      mList.Location = new Point(5, 10);
      mList.Size = new Size(50, this.ClientSize.Height + 50);
      for (int ix = 0; ix < 100; ++ix) mList.Items.Add(ix);
      mList.SelectedIndexChanged += new EventHandler(mList_SelectedIndexChanged);
    }

    void mList_SelectedIndexChanged(object sender, EventArgs e) {
      MessageBox.Show(mList.SelectedIndex.ToString());
    }

    protected override void Dispose(bool disposing) {
      // Moved from Designer.cs file
      if (disposing) mList.Dispose();
      if (disposing && (components != null)) {
        components.Dispose();
      }
      base.Dispose(disposing);
    }

  }