如何重寫userControl屬性

Question

IDE：C＃.net，WINFORMS，.net 4.0

嗨，您已經創建了一個userControl，並且我想創建一個屬性，如果啟用的用戶控件為false，則將背景圖像更改為imgDisabled.jpg其他imgEnabled.jpg

請告訴我如何覆蓋usercontrol的Enabled屬性並將此功能添加到其中。

  private void onPropertyChanged()
    {
        if (this.Enabled)
            this.BackgroundImage = Properties.Resources.imgEnabled;
        else
            this.BackgroundImage = Properties.Resources.imgDisabled;
    }

Answer 1

重寫基本Control類的虛擬OnEnabledChanged方法：

protected override void OnEnabledChanged(EventArgs e)
{
  base.OnEnabledChanged(e);
  if (this.Enabled)
    this.BackgroundImage = Properties.Resources.imgEnabled;
  else
    this.BackgroundImage = Properties.Resources.imgDisabled;
}

Answer 2

請使用這樣的事件提示器

class CustomProperty：屬性{公共事件EventHandler SelectionChanged;

private int _selectionStart;
private int _selectionLength;

protected override void OnMouseDown(MouseEventArgs e)
{
    _selectionStart = SelectionStart;
    _selectionLength = SelectionLength;

    base.OnMouseDown(e);
}

protected override void OnMouseUp(MouseEventArgs e)
{
    if (null != SelectionChanged && (_selectionStart != SelectionStart || _selectionLength != SelectionLength))
        SelectionChanged(this, EventArgs.Empty);

    base.OnMouseUp(e);
}

}