当Winforms控件被添加到表单时，Winforms控件是否引发事件

Question

我正在处理一些自定义的Control类，并且需要对它们进行初始化，而这些初始化依赖于它们被添加到表单中。发生这种情况时会发生事件吗？

我觉得这个样本就足够了，以显示我想要做的事：

public interface IMyForm 
{ 
    ISomeObject SomeObject {get; set; } 
} 

class MyForm : IMyForm 
{ 
    //eg InitializeComponent() as well as several others called at later points 
    private MethodThatAddsAControl() 
    { 
     MyControl newControl = new MyControl(); 
     //other initialization as needed 

     //does this raise an event in MyControl I can use to call 
     //InitializationAfterBeingAddedToForm()? 
     this.Controls.Add(newControl); 
    } 
} 


class MyControl : Control 
{ 
    InitializationAfterBeingAddedToForm() 
    { 
     //can't be done in the constructor because at that point FindForm() will return null 
     (FindForm() as IMyForm).SomeObject.AnEvent += new EventHandler(SomeObject_AnEvent); 
    } 
} 

这是谈到了更加困难比我初步实现了，我想我将不得不结合博卢和麦克杜尔的建议。问题是，虽然有些MyControl被直接添加到表单，在这种情况下Bolu的解决方案完美地工作。其他人被添加到面板，而不是直接添加到表单。我想我已经拼凑了一个包含Bolu解决方案的前一种解决方案，并对其进行了一些修改，以处理事件由正在添加的面板而不是其中的MyControl引发的情况，而Mikes则负责处理MyControl s在构造函数完成运行后被添加到面板中。我必须在明天早上进行更多测试，然后才能确信它已经奏效。通过波鲁请求时，我尝试用他的建议在设计

错误消息：

Failed to create component 'MyControl'. The error message follows: 
'System.MissingMethodException: Constructor on type 'MyNamespace.MyControl' not found. 
    at System.RuntimeType.CreateInstanceImpl(BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes) 
    at System.Activator.CreateInstance(Type type, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes) 
    at System.ComponentModel.Design.DesignSurface.CreateInstance(Type type) 
    at Microsoft.VisualStudio.Design.VSDesignSurface.CreateInstance(Type type) 
    at System.ComponentModel.Design.DesignerHost.System.ComponentModel.Design.IDesignerHost.CreateComponent(Type componentType, String name) 
    at System.ComponentModel.Design.DesignerHost.System.ComponentModel.Design.IDesignerHost.CreateComponent(Type componentType) 
    at System.Drawing.Design.ToolboxItem.CreateComponentsCore(IDesignerHost host) 
    at System.Drawing.Design.ToolboxItem.CreateComponentsCore(IDesignerHost host, IDictionary defaultValues) 
...' 

和到位的构造函数时，我得到了错误。

public MyControl(Form parent) 
{ 
    _parent = parent as IMyForm; 
    parent.ControlAdded += new ControlEventHandler(parent_ControlAdded); 
    Initialize(); //does rest of initialization 
} 

public TimelineControl(Form parent, Panel container) 
{ 
    _parent = parent as IMyForm; 
    container.ControlAdded += new ControlEventHandler(parent_ControlAdded); 
    Initialize(); //does rest of initialization 
} 

Answer 1

尝试ParentChanged事件。

Answer 2

为什么不在MyControl中实现自定义事件？

本文解释的方法：

http://ondotnet.com/pub/a/dotnet/2002/04/15/events.html

Answer 3

1. 在MyControl

   MyForm pForm;

2. 添加新MyForm对象传递一个MyForm参照MyControl时创建它：

   MyControl newControl = new MyControl（this）;

3. 然后注册您的MyForm对象的ControlAdded事件

   pForm.ControlAdded+=new ControlEventHandler(pForm_ControlAdded);

基于您的代码，它应该看起来像：

class MyForm : IMyForm 
{ 
    private MethodThatAddsAControl() //includes includes InitializeComponent as well as several others called at later 
    { 
     MyControl newControl = new MyControl(this); 
     //other initialization as needed 
     this.Controls.Add(newControl); //this will raise MyControl ：：pForm_ControlAdded 
    } 
} 


class MyControl : Control 
{ 
    Myform pForm; 
    public MyControl(MyForm ff) 
    { 
     InitializeComponent(); 
     pForm=ff; 
     pForm.ControlAdded+=new ControlEventHandler(pForm_ControlAdded); 
    } 

} 

编辑： 为MyControl你想添加到平底锅EL，只是通过面板的参考MyControl：

class MyForm : IMyForm 
     { 
      private MethodThatAddsAControl() //includes includes InitializeComponent as well as several others called at later 
      { 
      //create a MyControl object and add it to MyForm 
       MyControl newControl = new MyControl(this); 
      //other initialization as needed 
       this.Controls.Add(newControl); //this will raise MyControl::pForm_ControlAdded 

       //create a MyControl object and add it to MyPanel1 
       MyControl newControl = new MyControl(MyPanel1); //pass panel reference    
       MyPanel1.Controls.Add(newControl); //this will raise MyControl::pPanel_ControlAdded 
      } 
     } 


    class MyControl : Control 
    { 

     //// for control added to Form 
     Myform pForm; 
     public MyControl(MyForm ff) 
     { 
      InitializeComponent(); 
      pForm=ff; 
      pForm.ControlAdded+=new ControlEventHandler(pForm_ControlAdded); 
     } 

    ///now for control added to panel 
     MyPanel pPanel; 
     public MyControl(MyPanel pp) 
     { 
      InitializeComponent(); 
      pPanel=pp; 
      pPanel.ControlAdded+=new ControlEventHandler(pPanel_ControlAdded); 
     } 

    }