Usercontrol运行时宽度和高度

Question

我试图在VS2008中创建一个简单的用户控件(不是WPF),它实际上是SplitContainer一个按钮Panel1,当按下时,切换Panel2Collapsed属性并将控件的大小调整为大小Panel1.

以下是控件的基本内容:

private int _openHeight;
private int _closedHeight;

public MyUserControl(bool open)
{
  InitializeComponent();

  _openHeight = this.Height;
  _closedHeight = splitContainer1.SplitterDistance;
  Open = open;  
}    

private bool _open;
private bool Open
{
  get { return _open; }
  set 
  { 
    _open = value;
    splitContainer1.Panel2Collapsed = !_open;
    this.Height = _open ? _openHeight : _closedHeight;
  }
}

private void button1_Click(object sender, EventArgs e)
{
  Open = !Open;
}

问题是,this.HeightRuntime是控件在用户控件设计器中的值,而不是主窗体设计器中设计时设置的值.

任何帮助将不胜感激.

UPDATE

继Lucas的解决方案之后,这种方式意味着_openHeight只设置一次,从而产生了预期的效果:

private int? _openHeight;
private int _closedHeight;

public MyUserControl(bool open)
{
  InitializeComponent();

  //the _closedHeight doesn't change so can be defined in the constructor
  _closedHeight = splitContainer1.SplitterDistance;

  //set value
  Open = open;  

  this.SizeChanged += new EventHandler(MyUserControl_SizeChanged);
  this.Load += new EventHandler(MyUserControl_Load);
}    

void MyUserControl_SizeChanged(object sender, EventArgs e)
{
  //this event is called BEFORE the _Load event so gets the height set in the designer
  //  and not any changes at run time (e.g. when you collapse the control)

  if (_openHeight == null)
    _openHeight = this.Height;
}

private bool _open;
private bool Open
{
  get { return _open; }
  set 
  { 
    _open = value;

    if (_open)
    {
      //sets height only if it has been initialized
      if (_openHeight != null)
        this.Height = (int)_openHeight;
    }
    else
    {
      this.Height = (int)_closedHeight;
    }
  }
}

void MyUserControl_Load(object sender, EventArgs e)
{
  //now that control is loaded, set height
  Open = Open;
}

private void button1_Click(object sender, EventArgs e)
{
  Open = !Open;
}

Answer 1

你正在它的构造函数中读取控件的Height属性,这意味着它可能在表单中显示之前.问题是,当需要在窗体中显示控件时,大小似乎会被调整.在此之前,它是控件设计器中设置的值,您现在正在获得该值.

解决问题的最简单方法是Height在确定控件已经在窗体中绘制时读取值,即可以从open控件的构造函数中获取参数,添加一个初始化的新方法,Open并_closedHeight在Load事件中调用它.表格.

像这样的东西:

public MyUserControl()
{
    InitializeComponent(); 
}

public AdjustControlSize(bool open)
{
    _openHeight = this.Height;
    _closedHeight = splitContainer1.SplitterDistance;
    Open = open; 
}

//the rest of the control's code is unchanged
...

然后AdjustControlSize从form的Load事件中调用方法.

具有事件机制的解决方案

您还可以使用控件自己的事件来Height适当地读取.这样您就不必更改Form代码中的任何内容.

所以,在这种情况下,代码看起来像这样(虽然我没有测试过):

public MyUserControl(bool open)
{
    InitializeComponent();

    _openHeight = this.Height;
    _closedHeight = splitContainer1.SplitterDistance;
    Open = open;
    this.SizeChanged += new EventHandler(MyUserControl_SizeChanged);
}

void CustomPictureBox_SizeChanged(object sender, EventArgs e)
{
    _openHeight = this.Height;
    _closedHeight = splitContainer1.SplitterDistance;
}

这样,控件可以在每次改变尺寸时自行调整.