[转]C#Windows窗体打开图像与保存

转载自：http://blog.csdn.net/gufengcangying

                         

其中各个控件相应的属性设置等等，在Form1.Desigener .cs中有相应的代码，如下：

            // 
            // open
            // 
            this.open.Location = new System.Drawing.Point(37, 46);
            this.open.Name = "open";
            this.open.Size = new System.Drawing.Size(75, 23);
            this.open.TabIndex = 0;
            this.open.Text = "打开图像";
            this.open.UseVisualStyleBackColor = true;
            this.open.Click += new System.EventHandler(this.open_Click);
            // 
            // save
            // 
            this.save.Location = new System.Drawing.Point(37, 92);
            this.save.Name = "save";
            this.save.Size = new System.Drawing.Size(75, 23);
            this.save.TabIndex = 1;
            this.save.Text = "保存图像";
            this.save.UseVisualStyleBackColor = true;
            this.save.Click += new System.EventHandler(this.save_Click);
            // 
            // close
            // 
            this.close.Location = new System.Drawing.Point(37, 138);
            this.close.Name = "close";
            this.close.Size = new System.Drawing.Size(75, 23);
            this.close.TabIndex = 2;
            this.close.Text = "关闭";
            this.close.UseVisualStyleBackColor = true;
            this.close.Click += new System.EventHandler(this.close_Click);  

            // 
            // Form1
            // 
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 12F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(784, 562);
            this.Controls.Add(this.close);
            this.Controls.Add(this.save);
            this.Controls.Add(this.open);
            this.Name = "Form1";
            this.Text = "图像处理";
            this.Load += new System.EventHandler(this.Form1_Load);
            this.Paint += new System.Windows.Forms.PaintEventHandler(this.Form1_Paint);
            this.ResumeLayout(false);
            this.PerformLayout();

//

在Form1.cs中首先声明如下：

      其中需要导入的命名空间有：using System.Drawing;

        //文件名
        private string curFileName;
        //图像对象
        private System.Drawing.Bitmap curBitmap;

其余的代码如下：

打开文件——

        /// <summary>
        /// 打开图像文件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void open_Click(object sender, EventArgs e)
        {
            //创建OpenFileDialog
            OpenFileDialog opnDlg = new OpenFileDialog();
            //为图像选择一个筛选器
            opnDlg.Filter = "所有图像文件|*.bmp;*.pcx;*.png;*.jpg;*.gif;" +
                "*.tif;*.ico;*.dxf;*.cgm;*.cdr;*.wmf;*.eps;*.emf|" +
                "位图(*.bmp;*.jpg;*.png;...)|*.bmp;*.pcx;*.png;*.jpg;*.gif;*.tif;*.ico|" +
                "矢量图(*.wmf;*.eps;*.emf;..)|*.dxf;*.cgm;*.cdr;*.wmf;*.eps;*.emf";
            //设置对话框标题
            opnDlg.Title = "打开图像文件";
            //启用帮助按钮
            opnDlg.ShowHelp = true;
            //如果选择的结果为打开，则选定文件
            if(opnDlg.ShowDialog()==DialogResult.OK)
            {
                //读取当前选中的文件名称
                curFileName = opnDlg.FileName;

            }
            try
            {
               //使用 Image.FromFile创建图像对象；
                curBitmap = (Bitmap)System.Drawing.Image.FromFile(curFileName);
            }
            catch(Exception ex)
            {
                //显示异常；
                MessageBox.Show(ex.Message);
            }
            Invalidate();

        }

保存图像——

  /// <summary>
        /// 保存图像文件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void save_Click(object sender, EventArgs e)
        {
            //如果没有创建图像，则退出
            if(curBitmap==null)
            {
                return;
            }
            //调用SaveFileDialog
            SaveFileDialog saveDlg = new SaveFileDialog();
            //设置对话框标题
            saveDlg.Title = "保存为";
            //读写已存在文件时提示用户
            saveDlg.OverwritePrompt = true;
            //为图像选择一个筛选器
            saveDlg.Filter = "BMP文件(*.bmp)|*.bmp|"+"Gif文件(*.gif)|*.gif|"+
                "JPEG文件(*.jpg)|*.jpg|"+"PNG文件(*.png)|*.png";
            //启用“帮助”按钮
            saveDlg.ShowHelp = true;
            //如果选择了格式，则保存图像
            if(saveDlg.ShowDialog()==DialogResult.OK)
            {
                //获取用户选择的文件名
                string fileName = saveDlg.FileName;
                //获取用户选择的扩展名
                string strFilExtn = fileName.Remove(0,fileName.Length-3);
                //保存文件
                switch(strFilExtn)
                {
                    case "bmp":
                        //bmp格式；
                        curBitmap.Save(fileName,System.Drawing.Imaging.ImageFormat.Bmp);
                        break;
                    case "jpg":
                        curBitmap.Save(fileName, System.Drawing.Imaging.ImageFormat.Jpeg);
                        break;
                    case "gif":
                        curBitmap.Save(fileName, System.Drawing.Imaging.ImageFormat.Gif);
                        break;
                    case "tif":
                        curBitmap.Save(fileName, System.Drawing.Imaging.ImageFormat.Tiff);
                        break;
                    case "png":
                        curBitmap.Save(fileName, System.Drawing.Imaging.ImageFormat.Png);
                        break;
                    default:
                        break;

                }
            }
        }

关闭窗体——

        /// <summary>
        /// 关闭窗体，突出程序；
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void close_Click(object sender, EventArgs e)
        {
            this.Close();
        }

Paint事件——

很多人不明白这个事件是干什么用的，有了前面的准备工作以后，你要打开一个图像，必须要绘制到Form上，Paint事件就是画图的，在本程序中就是把要打开的图像

画到窗体上；

        /// <summary>
        /// Paints事件；
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void Form1_Paint(object sender, PaintEventArgs e)
        {
            //获取Graphics对象；
            Graphics g = e.Graphics;
            if(curBitmap!=null)
            {
                //使用DrawImage方法绘制图像
                //160,20：即显示在窗体上的坐标
                //curBitmap.Width,curBitmap.Height：即要显示的宽度与高度；本例一律原大小显示；
                g.DrawImage(curBitmap,160,20,curBitmap.Width,curBitmap.Height);

            }
        }

————————————————————————————————代码段结束；

 运行效果如下图：

（1）打开文件并显示：

（2）保存图像：