让自定义控件成为容器
我希望自定义的控件打开后,可以将工具栏上的控件拖到该自定义控件上。观察了Pannel控件,似乎简单得很。
继承自ScrollableControl,而ScrollableControl继承自Control。两个类都没有重写绘制,只是增加一些属性和重写某些属性值。而Control有一个Controls的集合属性。似乎已做了大部分的事。
我尝试直接往Control.Controls添加一个Button
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
public class TrackPannel:Control
{
//...
private void drawTrack(Graphics gc,Rectangle rect)
{
int iBottonY = rect.Y + rect.Height;
int iCur = 0;
//int iIndex = 0;
while (iCur < rect.Width)
{
//iIndex++;
iCur = iCur + this.TackSpacing;
gc.DrawLine(Pens.Black, iCur, 2, iCur, iBottonY);
}
Button btn = new Button();
btn.Click += new EventHandler(btn_Click);
this.Controls.Add(btn);
}
//
{
//...
private void drawTrack(Graphics gc,Rectangle rect)
{
int iBottonY = rect.Y + rect.Height;
int iCur = 0;
//int iIndex = 0;
while (iCur < rect.Width)
{
//iIndex++;
iCur = iCur + this.TackSpacing;
gc.DrawLine(Pens.Black, iCur, 2, iCur, iBottonY);
}
Button btn = new Button();
btn.Click += new EventHandler(btn_Click);
this.Controls.Add(btn);
}
//
Button能正常显示,并接收到点击事件。证明我的想法是对的。再细看ScrollableControl,原来需要两步
1.设置ControlStyles.ContainerControl
2.设置Designer
以下是修改后的代码。
![](https://images.cnblogs.com/OutliningIndicators/ExpandedBlockStart.gif)
[Designer("System.Windows.Forms.Design.ParentControlDesigner,System.Design",
typeof(System.ComponentModel.Design.IDesigner))]
public class TrackPannel:Control
{
/// <summary>
/// 构造函数
/// </summary>
public TrackPannel()
{
base.SetStyle(ControlStyles.UserPaint, true);
base.SetStyle(ControlStyles.ContainerControl, true);
}
//...
typeof(System.ComponentModel.Design.IDesigner))]
public class TrackPannel:Control
{
/// <summary>
/// 构造函数
/// </summary>
public TrackPannel()
{
base.SetStyle(ControlStyles.UserPaint, true);
base.SetStyle(ControlStyles.ContainerControl, true);
}
//...
“base.SetStyle(ControlStyles.UserPaint, true);”是告诉程序用控件自己重写的OnPaint。重写了还不行,还要非得设置这个!一时半会,真让人摸不着边。