Question

我有一个自定义WinForms用户控件，看起来像一个组合框，但是打开一个ToolStripDropDown，它包含另一个名为NumericFilterPanel的自定义用户控件，它有一个复选框，一个组合框和一个文本框。

问题在于，当用户单击选择嵌入在下拉控件中的组合框的选项时，会导致父下拉隐藏。

我设置了ToolStripDropDown.AutoClose = false，它修复了原始问题，但现在我很难检测到下拉列表失去焦点的所有情况，例如当用户点击父窗体或切换程序时。有时下拉列表仍然可见且最顶层。

有没有办法保持AutoClose = true并阻止嵌入式组合框关闭父下拉列表，还是有办法始终检测下拉列表何时失去焦点，以便我可以手动关闭它？

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

  namespace mviWinControls
  {
    public partial class NumericRangeDropDown : UserControl
    {
      private const int ARROW_HEIGHT = 4;
      private Brush arrowBrush = new SolidBrush(Color.FromArgb(77, 97, 133));

      private ToolStripDropDown _dropdown;
      private ToolStripControlHost _host;
      private NumericFilterPanel _filter;

      public NumericRangeDropDown()
      {
        InitializeComponent();

        _filter = new NumericFilterPanel();
        _filter.DropDown = this;

        _host = new ToolStripControlHost(_filter);
        _host.Margin = Padding.Empty;
        _host.Padding = Padding.Empty;

        _dropdown = new ToolStripDropDown();
        _dropdown.Margin = Padding.Empty;
        _dropdown.Padding = Padding.Empty;
        _dropdown.AutoClose = false;  // Use this because panel has a combobox.  https://social.msdn.microsoft.com/Forums/windows/en-US/dd95b982-820e-4807-8a1f-79c74acab3f8/two-problems-toolstripdropdown?forum=winforms
        _dropdown.Items.Add(_host);
        _dropdown.Leave += new System.EventHandler(this.DropDown_Leave);

        this.Leave += new System.EventHandler(this.DropDown_Leave);
      }

      /// <summary> 
      /// Clean up any resources being used.
      /// </summary>
      /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
      protected override void Dispose(bool disposing)
      {
        if (disposing)
        {
          if (components != null) components.Dispose();
          if (_dropdown != null) _dropdown.Dispose();
        }
        base.Dispose(disposing);
      }

      public override string Text
      {
        get
        {
          return base.Text;
        }
        set
        {
          base.Text = value;
          _filter.SetValue(value);
        }
      }

      protected override void OnPaint(PaintEventArgs e)
      {
        //base.OnPaint(e);
        TextBox _txtDraw = new TextBox();

        _txtDraw.Width = this.Width;

        using (Bitmap bmp = new Bitmap(_txtDraw.Width, _txtDraw.Height))
        {
          _txtDraw.DrawToBitmap(bmp, new Rectangle(0, 0, _txtDraw.Width, _txtDraw.Height));
          e.Graphics.DrawImage(bmp, 0, 0);
        }

        StringFormat format = new StringFormat();
        format.Alignment = StringAlignment.Near;
        format.FormatFlags = StringFormatFlags.NoWrap;
        format.LineAlignment = StringAlignment.Center;

        using (Brush b = new SolidBrush(this.ForeColor))
          e.Graphics.DrawString(this.Text, this.Font, b, this.DisplayRectangle, format);

        Point[] arrowPoints = new Point[] { new Point(this.Width - ARROW_HEIGHT * 3 - 2, (this.Height - ARROW_HEIGHT) / 2),
                                            new Point(this.Width - ARROW_HEIGHT + 1 - 2, (this.Height - ARROW_HEIGHT) / 2),
                                            new Point(this.Width - ARROW_HEIGHT * 2 - 2, this.Height - (this.Height - ARROW_HEIGHT) / 2) };

        e.Graphics.FillPolygon(arrowBrush, arrowPoints );

      }

      private void DropDown_Leave(object sender, EventArgs e)
      {
        HideDropDown();
        this.Text = _filter.SummaryText();
      }

      private void NumericRangeDropDown_Click(object sender, EventArgs e)
      {
        if (_dropdown.Visible)
          HideDropDown();
        else
          ShowDropDown();
      }

      public void ShowDropDown()
      {
        _dropdown.Show(this, new Point(0, this.Height), ToolStripDropDownDirection.Default);
        _dropdown.BringToFront();
        //_dropdown.Focus();
        _filter.Select();
        _filter.Focus();
      }

      public void HideDropDown()
      {
        _dropdown.Close();
        this.Invalidate();
      }

    }
  }

Answer 1

这是一个组合框，可以自动为您禁用和启用主机控件上的AutoClose属性。

来源（我在示例中将其修改为组合框，而不是DatePicker）：http://www.queasy.me/programming/questions/13919634/tool+strip+toolstripdropdownbutton+close+and+lose+window+focus

public partial class CComboBox : ComboBox
{
    private bool savedAutoClose;

    public CComboBox()
    {
        InitializeComponent();
    }

    protected override void OnDropDownClosed(EventArgs e)
    {
        if (this.Parent != null)
        {
            var dropDownHost = this.Parent.Parent as ToolStripDropDown; // recursive instead?
            if (dropDownHost != null)
                dropDownHost.AutoClose = savedAutoClose; // restore the parent's AutoClose preference
        }

        base.OnDropDownClosed(e);
    }

    protected override void OnDropDown(EventArgs e)
    {
        if (this.Parent != null)
        {
            var dropDownHost = this.Parent.Parent as ToolStripDropDown; // recursive instead?
            if (dropDownHost != null)
            {
                savedAutoClose = dropDownHost.AutoClose;
                // ensure that our parent doesn't close while the calendar is open
                dropDownHost.AutoClose = false;
            }
        }
        base.OnDropDown(e);
    }
}

WinForms用户控件具有ComboBox，导致ToolStripDropDown自动关闭

1 个答案: