实例介绍
【实例简介】C#拖拉控件及拖拽文件上传，拖拉控件改变大小及改变位置不会超出父容器边界
【实例截图】
【核心代码】
【实例截图】
【核心代码】
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace DropForms
{
class DragFrame
{
private const int Box_Size = 8;
private Color Box_Color = Color.White;
private Control control;
private Label[] label = new Label[8];
private int Initial_Left;
private int Initial_Top;
private int Initial_Width;
private int Initial_Height;
private int Initial_X;
private int Initial_Y;
private bool dragging;
private Cursor[] arrArrow = new Cursor[] {Cursors.SizeNWSE, Cursors.SizeNS,
Cursors.SizeNESW, Cursors.SizeWE, Cursors.SizeNWSE, Cursors.SizeNS,
Cursors.SizeNESW, Cursors.SizeWE};
private Cursor oldCursor;
private const int Min_Size = 20;
public DragFrame()
{
for(int i=0; i < 8; i )
{
label[i] = new Label();
label[i].TabIndex = i;
label[i].FlatStyle = 0;
label[i].BorderStyle = BorderStyle.FixedSingle;
label[i].BackColor = Box_Color;
label[i].Cursor = arrArrow[i];
label[i].Text = "";
label[i].BringToFront();
label[i].MouseDown = new MouseEventHandler(label_MouseDown);
label[i].MouseMove = new MouseEventHandler(this.label_MouseMove);
label[i].MouseUp = new MouseEventHandler(this.label_MouseUp);
}
}
public void WireControl(Control ctl)
{
ctl.Click = new EventHandler(this.SelectControl);
}
private void SelectControl(object sender, EventArgs e)
{
if(control is Control)
{
control.Cursor = oldCursor;
//移除任何预先存在的事件处理程序
control.MouseDown -= new MouseEventHandler(this.ctl_MouseDown);
control.MouseMove -= new MouseEventHandler(this.ctl_MouseMove);
control.MouseUp -= new MouseEventHandler(this.ctl_MouseUp);
control = null;
}
control = (Control)sender;
//添加用于移动所选控件的事件处理程序
control.MouseDown = new MouseEventHandler(this.ctl_MouseDown);
control.MouseMove = new MouseEventHandler(this.ctl_MouseMove);
control.MouseUp = new MouseEventHandler(this.ctl_MouseUp);
//将大小调整手柄添加到控件的容器
for (int i = 0; i < 8; i )
{
control.Parent.Controls.Add(label[i]);
label[i].BringToFront();
}
//在控件周围放置大小调整手柄
MoveHandles();
//显示大小调整手柄
ShowHandles();
oldCursor = control.Cursor;
control.Cursor = Cursors.SizeAll;
}
//设置大小调整手柄位置和大小
private void MoveHandles()
{
int sX = control.Left - Box_Size;
int sY = control.Top - Box_Size;
int sW = control.Width Box_Size;
int sH = control.Height Box_Size;
int hB = Box_Size / 2;
int[] arrPosX = new int[] { sX hB, sX sW / 2, sX sW - hB, sX sW - hB, sX sW - hB, sX sW / 2, sX hB, sX hB };
int[] arrPosY = new int[] { sY hB, sY hB, sY hB, sY sH / 2, sY sH - hB, sY sH - hB, sY sH - hB, sY sH / 2 };
for (int i = 0; i < 8; i )
{
label[i].SetBounds(arrPosX[i], arrPosY[i], Box_Size, Box_Size);
}
}
//显示大小调整手柄
private void ShowHandles()
{
if (control != null)
{
for (int i = 0; i < 8; i )
{
label[i].Visible = true;
}
}
}
//隐藏大小调整手柄
private void HideHandles()
{
for (int i = 0; i < 8; i )
{
label[i].Visible = false;
}
}
/// <summary>
/// 鼠标按下事件：记录当前控件位置和大小
/// </summary>
private void label_MouseDown(object sender, MouseEventArgs e)
{
dragging = true;
Initial_Left = control.Left;
Initial_Top = control.Top;
Initial_Height = control.Height;
Initial_Width = control.Width;
HideHandles();
}
/// <summary>
/// 鼠标移动事件：根据拖动的大小调整手柄调整所选控件的大小
/// 0 1 2
/// 7 3
/// 6 5 4
/// </summary>
private void label_MouseMove(object sender, MouseEventArgs e)
{
int left = control.Left;
int top = control.Top;
int width = control.Width;
int height = control.Height;
if (dragging)
{
switch (((Label)sender).TabIndex)
{
case 0: // 拖动左上角的大小调整框
left = Initial_Left e.X < Initial_Left Initial_Width - Min_Size ? Initial_Left e.X : Initial_Left Initial_Width - Min_Size;
top = Initial_Top e.Y < Initial_Top Initial_Height - Min_Size ? Initial_Top e.Y : Initial_Top Initial_Height - Min_Size;
width = Initial_Left Initial_Width - control.Left;
height = Initial_Top Initial_Height - control.Top;
break;
case 1: // 拖动上中点大小调整框
top = Initial_Top e.Y < Initial_Top Initial_Height - Min_Size ? Initial_Top e.Y : Initial_Top Initial_Height - Min_Size;
height = Initial_Top Initial_Height - control.Top;
break;
case 2: // 拖动右上角的大小调整框
top = Initial_Top e.Y < Initial_Top Initial_Height - Min_Size ? Initial_Top e.Y : Initial_Top Initial_Height - Min_Size;
width = (Min_Size > Initial_Width e.X ? Min_Size : (Initial_Width e.X left > control.Parent.ClientRectangle.Width ? control.Parent.ClientRectangle.Width - left : Initial_Width e.X));
height = Initial_Top Initial_Height - control.Top;
break;
case 3: // 拖动右中大小调整框
width = (Min_Size > Initial_Width e.X ? Min_Size : (Initial_Width e.X left > control.Parent.ClientRectangle.Width ? control.Parent.ClientRectangle.Width - left : Initial_Width e.X));
break;
case 4: // 拖动右下角的大小调整框
width = (Min_Size > Initial_Width e.X ? Min_Size : (Initial_Width e.X left > control.Parent.ClientRectangle.Width ? control.Parent.ClientRectangle.Width - left : Initial_Width e.X));
height = Initial_Height e.Y > Min_Size ? (Initial_Height e.Y top > control.Parent.ClientRectangle.Height ? control.Parent.ClientRectangle.Height - top : Initial_Height e.Y) : Min_Size;
break;
case 5: // 拖动底部中心大小调整框
height = Initial_Height e.Y > Min_Size ? (Initial_Height e.Y top > control.Parent.ClientRectangle.Height ? control.Parent.ClientRectangle.Height - top : Initial_Height e.Y) : Min_Size;
break;
case 6: // 拖动左下调整框
left = Initial_Left e.X < Initial_Left Initial_Width - Min_Size ? Initial_Left e.X : Initial_Left Initial_Width - Min_Size;
width = Initial_Left Initial_Width - control.Left;
height = Initial_Height e.Y > Min_Size ? (Initial_Height e.Y top > control.Parent.ClientRectangle.Height ? control.Parent.ClientRectangle.Height - top : Initial_Height e.Y) : Min_Size;
break;
case 7: // 拖动左中大小调整框
left = Initial_Left e.X < Initial_Left Initial_Width - Min_Size ? Initial_Left e.X : Initial_Left Initial_Width - Min_Size;
width = Initial_Left Initial_Width - control.Left;
break;
}
left = (left < 0) ? 0 : left;
top = (top < 0) ? 0 : top;
control.SetBounds(left, top, width, height);
}
}
/// <summary>
/// 鼠标释放事件：显示大小调整完后所选控件周围的大小调整手柄
/// </summary>
private void label_MouseUp(object sender, MouseEventArgs e)
{
dragging = false;
MoveHandles();
ShowHandles();
}
/// <summary>
/// 将鼠标指针置于鼠标下方的起始位置并隐藏大小调整手柄
/// </summary>
private void ctl_MouseDown(object sender, MouseEventArgs e)
{
dragging = true;
Initial_X = e.X;
Initial_Y = e.Y;
HideHandles();
}
/// <summary>
/// 重新定位拖动的控件
/// </summary>
private void ctl_MouseMove(object sender, MouseEventArgs e)
{
if (dragging)
{
int left = control.Left e.X - Initial_X;
int top = control.Top e.Y - Initial_Y;
int width = control.Width;
int height = control.Height;
left = (left < 0) ? 0 : ((left width > control.Parent.ClientRectangle.Width) ? control.Parent.ClientRectangle.Width - width : left);
top = (top < 0) ? 0 : ((top height > control.Parent.ClientRectangle.Height) ? control.Parent.ClientRectangle.Height - height : top);
control.Left = left;
control.Top = top;
}
}
/// <summary>
///
/// </summary>
private void ctl_MouseUp(object sender, MouseEventArgs e)
{
dragging = false;
}
}
}
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