嵌套面板：'孩子'不是这个父母的子控件

Question

我有一个继承自Panel的类。它包含嵌套在其中的第二个面板。当控件添加到此控件时，我实际上希望它们添加到内部面板。这里的目标是使用外部面板绘制一个特殊的边框，但是随后能够将内部面板的控件托管，就好像它是任何其他面板一样。

这里是我使用的基本代码：

public class TestPanel2 : Panel 
{ 
    private Panel innerPanel = new Panel(); 

    public TestPanel2() 
    { 
     this.Controls.Add(innerPanel); 
     this.ControlAdded += new ControlEventHandler(TestPanel2_ControlAdded); 
    } 

    void TestPanel2_ControlAdded(object sender, ControlEventArgs e) 
    { 
     if (e.Control != innerPanel) { 
      innerPanel.Controls.Add(e.Control); 
     } 
    } 
} 

当使用在设计这种控制，拖着子控件（如CheckBox）到它导致设计师报告：

'child' is not a child control of this parent 

我的理论是设计师为了自己的目的调用Controls.SetChildIndex（）或Controls.GetChildIndex（），并且这是触发错误。所以，我想加入以下属性添加到该类：

public new ControlCollection Controls 
    { 
     get { return innerPanel.Controls; } 
    } 

当我这样做，我也改变this.Controls的所有内部引用base.Controls。但是，这并没有解决问题。

有没有办法添加一个嵌套的面板，自动接收拖入它的控件？如果我更改代码，以便在运行时将子控件添加到innerControl中，它可以工作，但子控件的位置最终会出错，所以它不是一个很好的解决方案。

UPDATE：

不管出于什么值得注意的是，这里是什么，我试图做一个简单的示意图。我正在创建一个将被其他开发人员使用的工具包。它是一个专门的面板，其中包含一个自定义边框和标题栏。把它看作功能上类似于“GroupBox”控件。我希望他们能够将这个专门的面板拖到他们的表单上，然后在Designer中添加控件。 “innerPanel”需要是自己的面板，这是滚动的唯一区域（当需要滚动时）。

​​3210

Answer 1

你必须先删除该控件，然后将其添加到innerpanel。控制不能在两个通道同时：

void TestPanel2_ControlAdded(object sender, ControlEventArgs e) 
{ 
    if (e.Control != innerPanel) { 
     this.Controls.Remove(e.Control); 
     innerPanel.Controls.Add(e.Control); 
    } 
} 

Answer 2

Hans Passant我指出了正确的方向通过链接到这个讨论：

How do I provide designer support to a TabControl residing in a UserControl, so that I can drag/drop controls onto tab pages?

我还发现了一个示例项目，表明几乎完全控制我想创建：

http://www.codeproject.com/Articles/37830/Designing-Nested-Controls

这里是我的修订的版本控制：

[Designer(typeof(TestUserControlDesigner))] 
public partial class TestPanel3 : UserControl 
{ 
    private Panel innerPanel = new Panel(); 

    public TestPanel3() 
    { 
     InitializeComponent(); 
     this.Controls.Add(innerPanel); 
    } 

    [DesignerSerializationVisibility(DesignerSerializationVisibility.Content)] 
    public Panel ContentPanel 
    { 
     get { return innerPanel; } 
    } 
} 

internal class TestUserControlDesigner : ParentControlDesigner 
{ 
    public override void Initialize(System.ComponentModel.IComponent component) 
    { 
     base.Initialize(component); 
     EnableDesignMode((this.Control as TestPanel3).ContentPanel, "ContentPanel"); 
    } 
} 

这种方法的作品，虽然“innerPanel”可以在设计控制的“拖出来”。但是还有其他解决方案可以解决这个问题，这是一个很好的解决方案。

Answer 3

我知道这已经过去了几个月了，但请参阅此博客条目，了解如何使内部控件成为用户控件的内容控件。它会让你的生活变得容易很多，因为控制只能够放在你的内部面板上。

How can I drop controls within UserControl at Design time? 几件事情要考虑：1。 你想设计了用户控制当你的内板是可移动的和相当大的，但不是当你已经放弃了用户控件上的另一个设计表面

1. 为了实现这一点我创建的继承图a的ContentPanel，然后用于自定义设计，以除去在设计时上浆握把根据需要

A.下面是外板设计者 - 我实现将它嵌入到外部面板中它可以与被施加到所述外类

[Designer(typeof(YourUserControl.Designer))] 
public partial class YourUserControl : UserControl 

#region Designer - Friend class 

    /// <summary> 
    /// Exposes the internal panel as content at design time, 
    /// allowing it to be used as a container for other controls. 
    /// 
    /// Adapted 
    /// From: How can I drop controls within UserControl at Design time? 
    /// Link: http://blogs.msdn.com/b/subhagpo/archive/2005/03/21/399782.aspx 
    /// </summary> 
    internal class Designer : ParentControlDesigner 
    { 
     public override void Initialize(IComponent component) 
     { 
      base.Initialize(component); 

      var parent = (YourUserControl)component; 
      EnableDesignMode(parent.Content, "Content"); 
     } 
    } 

    #endregion 

B.这里是一个需要被添加到外板

#region Content - Used by the designer class 

    /// <summary> 
    /// Defines the control which can act as a container at design time. 
    /// In conjunction with other design time attributes and the designer 
    /// defined below, allows the user control to act as a container at 
    /// design time. This means other controls can be sited on the content 
    /// panel, such as a text boxes or labels, etc. 
    /// </summary> 
    [DesignerSerializationVisibility(DesignerSerializationVisibility.Content)] 
    public ContentPanel Content 
    { 
     get 
     { 
      return this.contentPanel1; 
     } 
    } 

    #endregion 

C.这里Content属性像这样一个设计属性来引用是用作内容面板的内部面板。在你的情况下，你需要在下面的代码中切换Dock和Anchor属性。我希望它始终处于停靠状态，而您会希望它始终停留，因为您在帖子中引用的标题和边框。

using System; 
using System.Collections; 
using System.Collections.Generic; 
using System.ComponentModel; 
using System.ComponentModel.Design; 
using System.Linq; 
using System.Windows.Forms; 
using System.Windows.Forms.Design; 
using System.Text; 
using System.Threading.Tasks; 

namespace j2associates.Tools.Winforms.Controls 
{ 
    [Designer(typeof(ContentPanel.Designer))] 
    public class ContentPanel : Panel 
    { 
     private ScrollableControl _parentScrollableControl; 

     public ContentPanel() 
      : base() 
     { 
      // Dock is always fill. 
      this.Dock = DockStyle.Fill; 
     } 

     protected override void OnParentChanged(EventArgs e) 
     { 
      base.OnParentChanged(e); 

      if (this.Parent != null) 
      { 
       Control parent = this.Parent; 
       while (parent != null && this.Parent.GetType() != typeof(ScrollableControl)) 
       { 
        parent = parent.Parent; 
       } 
       if (parent != null && parent.GetType() == typeof(ScrollableControl)) 
       { 
        _parentScrollableControl = (ScrollableControl)parent; 

        // Property value is retrieved from scrollable control panel. 
        this.AutoScroll = _parentScrollableControl.AutoScroll; 
       } 
      } 
     } 

     protected override void OnPaint(PaintEventArgs e) 
     { 
      base.OnPaint(e); 

      if (_parentScrollableControl != null) 
      { 
       this.AutoScroll = _parentScrollableControl.AutoScroll; 
      } 
     } 

     protected override void OnEnter(EventArgs e) 
     { 
      base.OnEnter(e); 

      this.AutoScroll = _parentScrollableControl != null ? _parentScrollableControl.AutoScroll : false; 
     } 

     #region Designer - Friend class 

     /// <summary> 
     /// Allows us to handle special cases at design time. 
     /// </summary> 
     internal class Designer : ParentControlDesigner 
     { 
      private IDesignerHost _designerHost = null; 
      private Control _parent = null; 

      #region Overrides 

      #region Initialize 

      public override void Initialize(IComponent component) 
      { 
       base.Initialize(component); 

       // Used to determine whether the content panel is sited on a form or on a user control. 
       _designerHost = (IDesignerHost)this.GetService(typeof(IDesignerHost)); 
       _parent = ((ContentPanel)component).Parent; 
      } 

      #endregion 

      #region SelectionRules 

      public override SelectionRules SelectionRules 
      { 
       get 
       { 
        SelectionRules selectionRules = base.SelectionRules; 

        // When hosted on a form, remove all resizing and moving grips at design time 
        // because the content panel is part of a composed user control and it cannot 
        // be moved nor can the dock property change. 
        // 
        // When not hosted on a form, then it is part of a user control which is being 
        // composed and it can be moved or the dock property changed. 
        if (!ReferenceEquals(_designerHost.RootComponent, _parent)) 
        { 
         selectionRules = SelectionRules.Visible | SelectionRules.Locked; 
        } 

        return selectionRules; 
       } 
      } 

      #endregion 

      #region PreFilterProperties 

      protected override void PreFilterProperties(System.Collections.IDictionary properties) 
      { 
       base.PreFilterProperties(properties); 

       // The Anchor property is not valid for a ContentPanel so just get rid of it. 
       properties.Remove("Anchor"); 
      } 

      #endregion 

      #region PostFilterProperties 

      protected override void PostFilterProperties(System.Collections.IDictionary properties) 
      { 
       // Hide the Anchor property so it cannot be changed by the developer at design time. 
       PropertyDescriptor dockDescriptor = (PropertyDescriptor)properties["Dock"]; 
       dockDescriptor = TypeDescriptor.CreateProperty(dockDescriptor.ComponentType, dockDescriptor, new Attribute[] { new BrowsableAttribute(false), new EditorBrowsableAttribute(EditorBrowsableState.Never)}); 
       properties[dockDescriptor.Name] = dockDescriptor; 

       // Hide the AutoScroll property so it cannot be changed by the developer at design time 
       // because it is set from the nearest panel of type scrollable control. 
       PropertyDescriptor autoScrollDescriptor = (PropertyDescriptor)properties["AutoScroll"]; 
       autoScrollDescriptor = TypeDescriptor.CreateProperty(autoScrollDescriptor.ComponentType, autoScrollDescriptor, new Attribute[] { new ReadOnlyAttribute(true) }); 
       properties[autoScrollDescriptor.Name] = autoScrollDescriptor; 

       // Make the Name property read only so it cannot be changed by the developer at design time 
       // because it is set from the nearest panel of type scrollable control. 
       PropertyDescriptor nameDescriptor = (PropertyDescriptor)properties["Name"]; 
       nameDescriptor = TypeDescriptor.CreateProperty(nameDescriptor.ComponentType, nameDescriptor, new Attribute[] { new ReadOnlyAttribute(true) }); 
       properties[nameDescriptor.Name] = nameDescriptor; 

       // Always call the base method last. 
       base.PostFilterProperties(properties); 
      } 

      #endregion 

      #endregion 
     } 

     #endregion 
    } 
} 

享受...

开始=>