新建一个windows自定义控件的项目
在界面上拖入：一个picturebox1 , 6个label,1个button
picturebox1命名为picBox,左边三个label的text改为：文件名称、文件大小、文件尺寸；右边的三个label的name改为lblName、lblLength、lblSize
button的name属性改为btnOpen.
代码如下：
namespace 自定义控件{public partial class UserControl1: UserControl{public UserControl1(){InitializeComponent();}private void btnOpen_Click(object sender, EventArgs e){OpenFileDialog ofdPic = new OpenFileDialog();ofdPic.Filter = "JPG(*.JPG;*.JPEG);gif文件(*.GIF)|*.jpg;*.jpeg;*.gif";ofdPic.FilterIndex = 1;ofdPic.RestoreDirectory = true;ofdPic.FileName = "";if (ofdPic.ShowDialog() == DialogResult.OK){string sPicPaht = ofdPic.FileName.ToString();System.IO.FileInfo fiPicInfo = new System.IO.FileInfo(sPicPaht);long lPicLong = fiPicInfo.Length / 1024;string sPicName = fiPicInfo.Name;string sPicDirectory = fiPicInfo.Directory.ToString();string sPicDirectoryPath = fiPicInfo.DirectoryName;Bitmap bmPic = new Bitmap(sPicPaht);if (lPicLong > 400){MessageBox.Show("此文件大小為" + lPicLong + "K；已超過最大限制的K范圍！");}else{Point ptLoction = new Point(bmPic.Size);if (ptLoction.X > picBox.Size.Width || ptLoction.Y > picBox.Size.Height){picBox.SizeMode = PictureBoxSizeMode.Zoom;}else{picBox.SizeMode = PictureBoxSizeMode.CenterImage;}}picBox.LoadAsync(sPicPaht);lblName.Text = sPicName;lblLength.Text = lPicLong.ToString() + " KB";lblSize.Text = bmPic.Size.Width.ToString() + "×" + bmPic.Size.Height.ToString();}}}}
3、鼠标右键点击项目名，重新生成下
4、新建一个常规winform界面项目，打开自定义控件的文件，找到控件项目想的Debug里面的dll文件，拖进当前项目的工具箱中
5、在当前的界面中就可以调用这个控件了
参考链接：/xiongxuanwen/article/details/2605109
