我正在尝试将图像从数据库加载到PictureBox.我使用以下代码加载我们的照片.我写了一些代码,但不知道我应该做什么来继续.

任何帮助将不胜感激.

private void button1_Click(object sender,EventArgs e)
    {
        sql = new sqlConnection(@"Data Source=PC-PC\PC;Initial Catalog=Test;Integrated Security=True");
        cmd = new sqlCommand();
        cmd.Connection = sql;
        cmd.CommandText = ("select Image from Entry where EntryID =@EntryID");
        cmd.Parameters.AddWithValue("@EntryID",Convert.ToInt32(textBox1.Text));
    }

在button1_Click中继续执行此操作：

// your code first here..

var da = new sqlDataAdapter(cmd);
var ds = new DataSet();
da.Fill(ds,"Images");
int count = ds.Tables["Images"].Rows.Count;

if (count > 0)
{ 
    var data = (Byte[])(ds.Tables["Images"].Rows[count - 1]["Image"]);
    var stream = new MemoryStream(data);
    pictureBox1.Image= Image.FromStream(sream);
}

我从openfiledialoge中选择文件,并在pictureBox中显示它,并在文本框中显示它,当我点击删除按钮我正在获得异常该进程无法访问该文件,因为它被另一个进程使用.
我搜索了很多这个异常得到解决,但我没有任何工作,当我试图关闭文件中的imagename的文件,即我在图片框中显示的文件;使用IsFileLocked方法,这会关闭和删除特定目录路径的所有文件,但是如何删除在pictureBox中显示的唯一文件,我将出错

public partial class RemoveAds : Form
    {
        OpenFileDialog ofd = null;
        string path = @"C:\Users\Monika\Documents\Visual Studio 2010\Projects\OnlineExam\OnlineExam\Image\"; // this is the path that you are checking.

        public RemoveAds()
        {
            InitializeComponent();
        }


        private void button1_Click(object sender,EventArgs e)
        {
            if (System.IO.Directory.Exists(path))
            {
                 ofd = new OpenFileDialog();
                ofd.InitialDirectory = path;
                DialogResult dr = new DialogResult();
                if (ofd.ShowDialog() == System.Windows.Forms.DialogResult.OK)
                {
                    Image img = new Bitmap(ofd.FileName);
                    string imgName = ofd.SafeFileName;
                    txtimageName.Text = imgName;
                    pictureBox1.Image = img.GetThumbnailImage(350,350,null,new IntPtr());
                    ofd.RestoreDirectory = true;
                }
            }
            else
            {
                return;
            } 
        }
private void button2_Click(object sender,EventArgs e)
        {
            //Image img = new Bitmap(ofd.FileName);
            string imgName = ofd.SafeFileName;  
             if (Directory.Exists(path))
             {

                 var directory = new DirectoryInfo(path);
                 foreach (FileInfo file in directory.GetFiles())
                 { if(!IsFileLocked(file))
                     file.Delete(); 
                 }
             }


        }
        public static Boolean IsFileLocked(FileInfo path)
        {
            FileStream stream = null;   
            try
            { //Don't change FileAccess to ReadWrite,//because if a file is in readOnly,it fails.
                stream = path.Open ( FileMode.Open,FileAccess.Read,FileShare.None ); 
            } 
            catch (IOException) 
            { //the file is unavailable because it is:
                //still being written to or being processed by another thread
                //or does not exist (has already been processed)
                return true;
            } 
            finally
            { 
                if (stream != null)
                    stream.Close();
            }   
            //file is not locked
            return false;
        }
    }

提前感谢任何帮助

(以前)接受的这个问题的答案是很差的做法.如果您在System.Drawing.Bitmap上使用 read the documentation,特别是为从文件创建位图的重载,您会发现：

The file remains locked until the Bitmap is disposed.

在您的代码中,您创建位图并将其存储在本地变量中,但在完成后您永远不会处理它.这意味着您的图像对象已超出范围,但尚未释放其对要删除的图像文件的锁定.对于实现Idisposable的所有对象(如Bitmap),您必须自己处理它们.例如参见this question(或搜索其他人 – 这是一个非常重要的概念！).

要正确解决问题,您只需要处理完成后的图像：

if (ofd.ShowDialog() == System.Windows.Forms.DialogResult.OK)
 {
      Image img = new Bitmap(ofd.FileName);  // create the bitmap
      string imgName = ofd.SafeFileName;
      txtimageName.Text = imgName;
      pictureBox1.Image = img.GetThumbnailImage(350,new IntPtr());
      ofd.RestoreDirectory = true;
      img.dispose();  // dispose the bitmap object
 }

请不要在下面的答案中采取建议 – 你几乎不需要调用GC.Collect,如果你需要做它来使事情工作,它应该是一个非常强大的信号,你正在做其他错误.

此外,如果您只想删除一个文件(您显示的位图),您的删除代码是错误的,并将删除目录中的每个文件(这只是重复Adel的要点).此外,与其保留一个全局的OpenFileDialog对象只是存储文件名,我建议摆脱那个,只保存文件信息：

FileInfo imageFileinfo;           //add this
//OpenFileDialog ofd = null;      Get rid of this

private void button1_Click(object sender,EventArgs e)
{
     if (System.IO.Directory.Exists(path))
     {
         OpenFileDialog ofd = new OpenFileDialog();  //make ofd local
         ofd.InitialDirectory = path;
         DialogResult dr = new DialogResult();
         if (ofd.ShowDialog() == System.Windows.Forms.DialogResult.OK)
         {
              Image img = new Bitmap(ofd.FileName);
              imageFileinfo = new FileInfo(ofd.FileName);  // save the file name
              string imgName = ofd.SafeFileName;
              txtimageName.Text = imgName;
              pictureBox1.Image = img.GetThumbnailImage(350,new IntPtr());
              ofd.RestoreDirectory = true;
              img.dispose();
         }
         ofd.dispose();  //don't forget to dispose it!
     }
     else
     {
         return;
     }
 }

然后在您的第二个按钮处理程序中,您可以删除您感兴趣的一个文件.

private void button2_Click(object sender,EventArgs e)
        {                
           if (!IsFileLocked(imageFileinfo))
            {                 
                imageFileinfo.Delete();
            }
        }