帶校驗列表的組合框

Question

如何在C＃中使用checkList的comboBox？

Answer 1

我一直在搞這個自己。這裏有一個Control的小樣本，它裏面有真正的CheckBox，而不僅僅是繪製它們。這樣你就可以真正使用CheckBox類所提供的一切。它用一個繼承ToolStripDropDownMenu的自定義工具取代了ComboBox的常規下拉菜單，該工具允許您將實際控件添加到ToolStripDropDownMenu中，並可以解決每次單擊某個項目時下拉關閉的問題。你顯然想要擴展MyComboBox類來適應你的需求，但它應該是一個很好的開始。

public partial class Form1 : Form 
{ 
    public Form1() 
    { 
     InitializeComponent(); 
     var mcb = new MyComboBox() { Left = 6, Top = 6 }; 
     this.Controls.Add(mcb); 

     for (int i = 0; i < 20; i++) 
     { 
      mcb.AddItem("Item " + i.ToString()); 
     } 
    } 
} 

public class MyComboBox : ComboBox 
{ 
    private MyDropDown _dropDown; 

    public MyComboBox() 
    { 
     _dropDown = new MyDropDown() { Width = 200, Height = 200 }; 
    } 

    public void AddItem(string text) 
    { 
     _dropDown.AddControl(new CheckBox() { Text = text }); 
    } 

    public void ShowDropDown() 
    { 
     if (_dropDown != null) 
     { 
      _dropDown.Show(this); 
     } 
    } 

    protected override void WndProc(ref Message m) 
    { 
     if (m.Msg == WndUI.WM_REFLECT + WndUI.WM_COMMAND) 
     { 
      if (WndUI.HIWORD(m.WParam) == WndUI.CBN_DROPDOWN) 
      { 
       ShowDropDown(); 
       return; 
      } 
     } 
     base.WndProc(ref m); 
    } 
} 

[ToolboxItem(false)] 
public class MyDropDown : ToolStripDropDownMenu 
{ 
    public MyDropDown() 
    { 
     this.ShowImageMargin = this.ShowCheckMargin = false; 
     this.AutoSize = false; 
     this.DoubleBuffered = true; 
     this.Padding = Margin = Padding.Empty; 
    } 

    public int AddControl(Control control) 
    { 
     var host = new ToolStripControlHost(control); 
     host.Padding = host.Margin = Padding.Empty; 
     host.BackColor = Color.Transparent; 
     return this.Items.Add(host); 
    } 

    public void Show(Control control) 
    { 
     Rectangle area = control.ClientRectangle; 
     Point location = control.PointToScreen(new Point(area.Left, area.Top + area.Height)); 
     location = control.PointToClient(location); 
     Show(control, location, ToolStripDropDownDirection.BelowRight); 
     this.Focus(); 
    } 
} 

public static class WndUI 
{ 
    public const int 
     WM_USER = 0x0400, 
     WM_REFLECT = WM_USER + 0x1C00, 
     WM_COMMAND = 0x0111, 
     CBN_DROPDOWN = 7; 

    public static int HIWORD(IntPtr n) 
    { 
     return HIWORD(unchecked((int)(long)n)); 
    } 

    public static int HIWORD(int n) 
    { 
     return (n >> 16) & 0xffff; 
    } 
} 

Answer 2

編輯：這是更適合我認爲：http://www.codeproject.com/KB/combobox/CheckComboBox.aspx

我發現這個鏈接：http://www.codeproject.com/KB/combobox/extending_combobox.aspx希望它能幫助。