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winforms控件添加到窗体时是否引发事件

custom-controls events winforms c#

8

Dan Is Fiddling By Firelight Leniency · 技术社区 · 14 年前

我正在做一些定制 Control 类,需要对它们进行一些初始化,这取决于它们被添加到表单中。发生这种情况时是否会发生火灾?

我认为这个样本应该足以显示我正在尝试做的事情:

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);
    }
}

事实证明,这比我最初意识到的要困难得多,我想我必须把博卢和迈克·多尔的建议结合起来。问题是当一些 MyControl s直接添加到形式中,在这种情况下,bolu的解决方案工作得很好。其他的则添加到面板中,而不是直接添加到表单中。我想我已经拼凑出了一个涉及Bolu对前一个案例的解决方案,并做了一些修改,以处理由添加的小组引发的事件,而不是 我的控制 在里面,米克负责处理 我的控制 在构造函数完成运行后将添加到面板中。明天早上我得再做一次测试,然后才能确信它能起作用。

当我尝试在设计器中使用他的建议时,Bolu请求的错误消息:

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)
...'

当我得到错误时,构造器就就位了。

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
}

3 回复 | 直到 7 年前

1

10

Mike Dour 14 年前

尝试 ParentChanged 事件。

2

1

Bolu 14 年前

添加新的 MyForm 中的对象 MyControl

MyForm pForm;
通过A 肌样的 参考 我的控制 创建时:

mycontrol newcontrol=新mycontrol(this);
然后注册 ControlAdded 您的活动 肌样的 对象

pForm.ControlAdded+=new ControlEventHandler(pForm_ControlAdded);

根据您的代码,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 ï¼ï¼pForm_ControlAdded
    }
}


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

}

编辑: 对于要添加到面板的mycontrol,只需将面板的引用传递给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);
        }

    }

3

-2

Russ Clarke 14 年前

为什么不在MyControl中实现自定义事件?

本文介绍了这种方法:

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