6

我正在尝试在 VS2008 中创建一个简单的用户控件（不是 WPF），它实际上是一个SplitContainer带有按钮的Panel1，当按下时，它会切换Panel2Collapsed属性并将控件的大小调整为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.Height在运行时是控件在用户控件设计器中的值，而不是在主窗体设计器的设计时设置的值。

任何帮助将不胜感激。

更新

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;
}
4

1 回答 1

5

您正在它的构造函数中读取控件的 Height 属性，这意味着它可能在它显示在表单中之前。问题是，当需要在表单中显示控件时，似乎调整了大小。在此之前，它是在控件设计器中设置的值，您现在可以得到它。

解决该问题的最简单方法是Height在您确定控件已在表单中绘制时读取该值，即您可以从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并在发生以下情况时_closedHeight调用它Load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
...

AdjustControlSize然后从表单的Load事件中调用方法。

事件机制的解决方案

您还可以Height在适当的时候使用控件自己的事件来读取。这样您就不必更改Form's 代码中的任何内容。

所以，在这种情况下，代码看起来像这样（虽然我还没有测试过）：

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，控件可以在每次更改其大小时自行调整。

于 2012-04-25T17:14:56.083 回答