C# 模拟VisualStudio窗体设计器拖放控件

/// <summary>
/// 控件样式基类定义
/// </summary>
public class DrawStyle
{
   protected bool _Drawing = false;
   
   protected Control _Container = null;
   protected Control _ActivedControl = null;
   
   protected Point _S; //Start Point.
   
   public virtual void BeginDraw(Control container, Point P) { }
   public virtual void EndDraw(Control container, Point P) { }
   public virtual void OnMove(Control container, Point P) { }
}


// 来源:www.CSFramework.com, C/S结构框架学习网

/// <summary>
/// 拖放TextBox控件
/// </summary>
public class DrawTextBox : DrawStyle
{
   private TextBox _CurrentText;
   
   public DrawTextBox() { }
   
   public override void BeginDraw(Control container, Point P)
   {
      _S = P;
      _Drawing = true;
      _Container = container;
      
      _CurrentText = new TextBox();
      _CurrentText.Multiline = true;
      _ActivedControl = _CurrentText;
      
      if (container.Controls.IndexOf(_ActivedControl) < 0)
      container.Controls.Add(_ActivedControl);
      
      _ActivedControl.Left = P.X;
      _ActivedControl.Top = P.Y;
   }
   
   public override void EndDraw(Control container, Point P)
   {
      //向右下方拖動X,Y為正數,當為負數時為反向拖動,需要更改Top,Left屬性
      _ActivedControl.Width = P.X - _S.X;
      _ActivedControl.Height = P.Y - _S.Y;
      _ActivedControl.Visible = true;
      
      _Drawing = false;
   }
   
   public override void OnMove(Control container, Point P)
   {
      if (_Drawing == false) return;
      if (_Container != container) return;
      
      //向右下方拖動X,Y為正數,當為負數時為反向拖動,需要更改Top,Left屬性
      _ActivedControl.Width = P.X - _S.X;
      _ActivedControl.Height = P.Y - _S.Y;
      _ActivedControl.Invalidate();
   }
   
}


// 来源:www.CSFramework.com, C/S结构框架学习网

/// <summary>
/// 自定义IDE设计器，控件容器
/// </summary>
public class MyCanvasDesigner
{
   private Control _Designer;
   
   public MyCanvasDesigner(Control control)
   {
      _Designer = control;
   }
   
   public void Clear()
   {
      _Designer.Controls.Clear();
   }
   
}


// 来源:www.CSFramework.com, C/S结构框架学习网

/// <summary>
/// 应用场景/控制器
/// </summary>
public class DrawController
{
   private static MyCanvasDesigner _Canvas = null;
   
   private static DrawStyle _CurrentDraw = null;
   
   /// <summary>
   /// 当前拖放的控件
   /// </summary>
   public static DrawStyle CurrentDraw
   {
      get
      {
         if (_CurrentDraw == null) _CurrentDraw = new DrawTextBox();
         return _CurrentDraw;
      }
      
      set { _CurrentDraw = value; }
   }
   
   /// <summary>
   ///当前Designer, 支持多个IDE设计器，控件容器
   /// </summary>
   public static MyCanvasDesigner CurrentDesigner
   {
      get { return _Canvas; }
      set { _Canvas = value; }
   }
}

// 来源:www.CSFramework.com, C/S结构框架学习网