C# Winform 相册功能，图片缩放，拖拽，预览图分页
效果
1.图片放大，缩小，拖拽功能
2.添加图片，分页功能
一、前言
在很多项目中也需要用到预览图片的功能，至于为什么加一个添加图片的功能，是因为有些项目，比如视觉相关的工作，会需要摄像机采集图片，然后显示在界面上，所以，图片也是一张一张的添加的，另外，就是分页功能，当预览图位置不够用时就会用到，所以我也加了进来。
当前软件的功能
1.添加图片
如果8个预览图都满了，会自动分页，就可以点击上一页，或者下一页了。
2.点击预览图显示大图
点击预览图，之前的拖拽和放大会自动复位
3.大图可以拖拽，放大，缩小
如果图片比较小，有这个功能就看到图片的更多细节了。
4.图片倒序排列
最后添加的图片，始终显示在最前面，这也就在分页上和常规的有点区别了，如图
如果你用的正序排列，可以看看这个帖子：
C# 分页计算 总页数、当前页数据集合_熊思宇的博客-CSDN博客
二、代码
新建一个winform项目，界面如下：
没有太复杂的界面，大图和预览图都是用的 PictureBox 控件 ，控件的名字，可以看下面的代码，在文章的最下面，我会附上这个Demo源码，有兴趣的可以下载。
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace 相册功能
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
//本地的相册列表
private string AlbumPath = Application.StartupPath + "\\Album";
//相册列表
private List PictureBoxList = new List();
//图片路径列表
private List FilesinfoList = new List();
//相册显示的图片列表
private List BitmapList = new List();
//pictureBox1的初始位置
private Point PicStartPos;
//pictureBox1的初始大小
private Size PicSize;
//测试用
int index = -1;
//当前页数
private int NowPage = 1;
//总页数
private int TotalPage = 1;
//鼠标滚轮缩放图片的增量值
private int ZoomStep = 20;
//鼠标是否在拖拽中
private bool IsMove = false;
//鼠标点击的位置
private Point MouseDownPoint;
private void Form1_Load(object sender, EventArgs e)
{
PicStartPos = pictureBox1.Location;
PicSize = pictureBox1.Size;
this.pictureBox1.MouseWheel += new MouseEventHandler(this.pictureBox1_MouseWheel);
PictureBoxList.Add(PictureBox_ImgList1);
PictureBoxList.Add(PictureBox_ImgList2);
PictureBoxList.Add(PictureBox_ImgList3);
PictureBoxList.Add(PictureBox_ImgList4);
PictureBoxList.Add(PictureBox_ImgList5);
PictureBoxList.Add(PictureBox_ImgList6);
PictureBoxList.Add(PictureBox_ImgList7);
PictureBoxList.Add(PictureBox_ImgList8);
//添加图片的点击事件
for (int i = 0; i < PictureBoxList.Count; i++)
{
PictureBoxList[i].Click += new System.EventHandler(PictureBoxClick);
}
DirectoryInfo directory = new DirectoryInfo(AlbumPath);
FileSystemInfo[] filesArray = directory.GetFileSystemInfos();
foreach (var item in filesArray)
{
if (item.Attributes != FileAttributes.Directory)
{
FilesinfoList.Add(item.FullName);
}
}
}
///
/// 上一页
///
///
///
private void Button_Back_Click(object sender, EventArgs e)
{
if (NowPage <= 1) return;
NowPage--;
for (int i = 0; i < PictureBoxList.Count; i++)
{
PictureBoxList[i].Image = null;
}
List list = GetPagesBitmap(NowPage);
for (int i = 0; i < list.Count; i++)
{
PictureBoxList[i].Image = list[i];
}
pictureBox1.Image = list[0];
//设置坐标
pictureBox1.Location = PicStartPos;
//设置控件宽高
pictureBox1.Size = PicSize;
Label_NumberOfPages.Text = string.Format("{0} / {1}", NowPage, TotalPage);
BackNextButtonType();
}
///
/// 下一页
///
///
///
private void Button_Next_Click(object sender, EventArgs e)
{
if (NowPage >= TotalPage) return;
NowPage++;
for (int i = 0; i < PictureBoxList.Count; i++)
{
PictureBoxList[i].Image = null;
}
List list = GetPagesBitmap(NowPage);
for (int i = 0; i < list.Count; i++)
{
PictureBoxList[i].Image = list[i];
}
pictureBox1.Image = list[0];
//设置坐标
pictureBox1.Location = PicStartPos;
//设置控件宽高
pictureBox1.Size = PicSize;
Label_NumberOfPages.Text = string.Format("{0} / {1}", NowPage, TotalPage);
BackNextButtonType();
}
///
/// 添加图片
///
///
///
private void Button_Add_Click(object sender, EventArgs e)
{
index++;
AddPicture(new Bitmap(FilesinfoList[index]));
if (index >= FilesinfoList.Count - 1)
index = -1;
}
///
/// 添加图片
///
///
private void AddPicture(Bitmap bitmap)
{
if (bitmap == null) return;
//添加到图片列表
BitmapList.Add(bitmap);
//界面预留图中显示
pictureBox1.Image = bitmap;
//设置坐标
pictureBox1.Location = PicStartPos;
//设置控件宽高
pictureBox1.Size = PicSize;
//计算当前总页数
int page = BitmapList.Count / PictureBoxList.Count;
int remainder = BitmapList.Count % PictureBoxList.Count;
TotalPage = remainder > 0 ? page + 1 : page;
Label_NumberOfPages.Text = string.Format("{0} / {1}", NowPage, TotalPage);
BackNextButtonType();
//让图片按逆向顺序显示
List reverseSort = new List();
for (int i = BitmapList.Count - 1; i >= 0; i--)
{
reverseSort.Add(BitmapList[i]);
}
for (int i = 0; i < reverseSort.Count; i++)
{
if (i <= 7)
PictureBoxList[i].Image = reverseSort[i];
}
}
///
/// 8张预览图片的点击事件
///
///
///
private void PictureBoxClick(Object sender, System.EventArgs e)
{
PictureBox pictureBox = (PictureBox)sender;
if (pictureBox != null && pictureBox.Image != null)
{
pictureBox1.Image = pictureBox.Image;
//设置坐标
pictureBox1.Location = PicStartPos;
}
}
///
/// 获取索引对应的图片
///
///
/// GetPagesBitmap(int index)
{
if (BitmapList.Count <= 0) return null;
//页数
int page = BitmapList.Count / PictureBoxList.Count;
//余数
int remainder = BitmapList.Count % PictureBoxList.Count;
//总页数
int allPage = remainder > 0 ? page + 1 : page;
if (index > allPage) return null;
//索引起点
int start = (index * PictureBoxList.Count) - PictureBoxList.Count;
//索引结束点
int end = (index * PictureBoxList.Count) - 1;
if (end > BitmapList.Count) end = BitmapList.Count - 1;
List reverseSort = new List();
for (int i = BitmapList.Count - 1; i >= 0; i--)
{
reverseSort.Add(BitmapList[i]);
}
List list = new List();
for (int i = start; i <= end; i++)
{
list.Add(reverseSort[i]);
}
if (list.Count > 0)
return list;
return null;
}
///
/// 上一页，下一页按钮状态
///
private void BackNextButtonType()
{
Button_Next.Enabled = true;
Button_Back.Enabled = true;
//现在页 = 总页数
if (NowPage == TotalPage)
Button_Next.Enabled = false;
//现在页 小于等于 1
if (NowPage <= 1)
Button_Back.Enabled = false;
}
private void pictureBox1_MouseDown(object sender, MouseEventArgs e)
{
if (pictureBox1.Image == null) return;
if (e.Button == MouseButtons.Left)
{
MouseDownPoint.X = Cursor.Position.X; //记录鼠标左键按下时位置
MouseDownPoint.Y = Cursor.Position.Y;
IsMove = true;
pictureBox1.Focus(); //鼠标滚轮事件(缩放时)需要picturebox有焦点
}
}
private void pictureBox1_MouseUp(object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Left)
{
IsMove = false;
}
}
private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
{
if (pictureBox1.Image == null) return;
pictureBox1.Focus(); //鼠标在picturebox上时才有焦点，此时可以缩放
if (IsMove)
{
int x, y; //新的pictureBox1.Location(x,y)
int moveX, moveY; //X方向，Y方向移动大小。
moveX = Cursor.Position.X - MouseDownPoint.X;
moveY = Cursor.Position.Y - MouseDownPoint.Y;
x = pictureBox1.Location.X + moveX;
y = pictureBox1.Location.Y + moveY;
pictureBox1.Location = new Point(x, y);
MouseDownPoint.X = Cursor.Position.X;
MouseDownPoint.Y = Cursor.Position.Y;
}
}
private void pictureBox1_MouseWheel(object sender, MouseEventArgs e)
{
if (pictureBox1.Image == null) return;
PictureBox pbox = pictureBox1;
int x = e.Location.X;
int y = e.Location.Y;
int ow = pbox.Width;
int oh = pbox.Height;
int VX, VY; //因缩放产生的位移矢量
if (e.Delta > 0) //放大
{
//第1步
pbox.Width += ZoomStep;
pbox.Height += ZoomStep;
//第2步
PropertyInfo pInfo = pbox.GetType().GetProperty("ImageRectangle", BindingFlags.Instance | BindingFlags.NonPublic);
Rectangle rect = (Rectangle)pInfo.GetValue(pbox, null);
//第3步
pbox.Width = rect.Width;
pbox.Height = rect.Height;
//Console.WriteLine(string.Format("宽：{0}，高：{1}",pbox.Width,pbox.Height));
}
if (e.Delta < 0) //缩小
{
//防止一直缩成负值
if (pbox.Width < 300)
return;
pbox.Width -= ZoomStep;
pbox.Height -= ZoomStep;
PropertyInfo pInfo = pbox.GetType().GetProperty("ImageRectangle", BindingFlags.Instance |
BindingFlags.NonPublic);
Rectangle rect = (Rectangle)pInfo.GetValue(pbox, null);
pbox.Width = rect.Width;
pbox.Height = rect.Height;
}
//第4步，求因缩放产生的位移，进行补偿，实现锚点缩放的效果
VX = (int)((double)x * (ow - pbox.Width) / ow);
VY = (int)((double)y * (oh - pbox.Height) / oh);
pbox.Location = new Point(pbox.Location.X + VX, pbox.Location.Y + VY);
}
}
}
代码中，鼠标缩放，拖拽功能，需要在控件里添加对应的事件，否则就没有效果了
运行后，效果就如文章开头所示，这个位置还是先不加图片了
源码：点击下载
结束
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