找不到文件的System.IO.File.Copy错误

Question

我正在尝试创建一个可以将图像复制到文件夹中的图像上传。问题是，当我试图将照片复制到文件夹时，出现了一个错误，表明它找不到文件。我的代码如下：

private void btn_Click(object sender, EventArgs e)
    {
        DialogResult result = folderBrowserDialog1.ShowDialog();
        if (result == DialogResult.OK)
        {
            //
            // The user selected a folder and pressed the OK button.
            // We print the number of files found.
            //
            string [] files = Directory.GetFiles(folderBrowserDialog1.SelectedPath);
        }
        if (result == DialogResult.Cancel)
        {
            return;
        }
            //001: Check the user selected a file and pressed ok button. Before opening the dialog
            //      set the filters
            dlgFileOpen.Filter = "Image Files(*.jpg; *.jpeg; *.bmp)|*.jpg; *.jpeg; *.bmp";
            string path = folderBrowserDialog1.SelectedPath;
            if (dlgFileOpen.ShowDialog() == DialogResult.OK)
            {
               // string file = Path.GetFileName(dlgFileOpen.FileName);
                string file = Path.GetFileName(dlgFileOpen.FileName);
                //string file2 = System.IO.Path.Combine(file, Path.GetFileName(dlgFileOpen.FileName));
                string newFileName = System.IO.Path.Combine(path, file);
                System.IO.File.Copy(file, newFileName, true);

                //image directory to be saved in database
                //txtSelectedFile.Text = newFileName;
            }
        }

    private void dlgFileOpen_FileOk(object sender, CancelEventArgs e)
    {
        string Required_Ext = ".jpeg .jpg .bmp";
        string selected_ext = Path.GetExtension(dlgFileOpen.FileName);
        int index = Required_Ext.IndexOf(selected_ext);
        //002: Inform the user to select correct extension
        if (index < 0)
        {
            MessageBox.Show("Extension Maaaan... Extension! Open only jpeg or bmp or jpg");
            e.Cancel = true;
        }
    }

答案：

private void btn_Click(object sender, EventArgs e)
    {
        DialogResult result = folderBrowserDialog1.ShowDialog();
        if (result == DialogResult.OK)
        {
            //
            // The user selected a folder and pressed the OK button.
            // We print the number of files found.
            //
            string [] files = Directory.GetFiles(folderBrowserDialog1.SelectedPath);
        }
        if (result == DialogResult.Cancel)
        {
            return;
        }
            //001: Check the user selected a file and pressed ok button. Before opening the dialog
            //      set the filters
            dlgFileOpen.Filter = "Image Files(*.jpg; *.jpeg; *.bmp)|*.jpg; *.jpeg; *.bmp";
            string path = folderBrowserDialog1.SelectedPath;
            if (dlgFileOpen.ShowDialog() == DialogResult.OK)
            {
               // string file = Path.GetFileName(dlgFileOpen.FileName);
                string file = Path.GetFileName(dlgFileOpen.FileName);
                //string file2 = System.IO.Path.Combine(file, Path.GetFileName(dlgFileOpen.FileName));
                string newFileName = System.IO.Path.Combine(path, file);
                System.IO.File.Copy(dlgFileOpen.FileName, newFileName, true);
                txtSelectedFile.Text = newFileName;
                MessageBox.Show("Image uploaded successful!");
            }
        }

    private void dlgFileOpen_FileOk(object sender, CancelEventArgs e)
    {
        string Required_Ext = ".jpeg .jpg .bmp";
        string selected_ext = Path.GetExtension(dlgFileOpen.FileName);
        int index = Required_Ext.IndexOf(selected_ext, StringComparison.CurrentCultureIgnoreCase);
        //002: Inform the user to select correct extension
        if (index < 0)
        {
            MessageBox.Show("Extension Maaaan... Extension! Open only jpeg or bmp or jpg");
            e.Cancel = true;
        }
    }

Answer 1

我认为您正在丢失源文件上的完整文件路径。

string file = Path.GetFileName(dlgFileOpen.FileName);  // "file" is the file name
string newFileName = System.IO.Path.Combine(path, file);
System.IO.File.Copy(file, newFileName, true);

替换此：

System.IO.File.Copy(file, newFileName, true);

有了这个：

System.IO.File.Copy(dlgFileOpen.FileName, newFileName, true);

关于你的另一个问题，来自评论：

"即使我用jpeg设置了文件管理器，为什么我的一张jpeg图片会触发我的错误消息？"

这很可能是一个案件敏感性问题。您的代码只允许使用小写文件扩展名；如果您选择的文件是".JPEG"（全部大写），它将失败并显示错误消息。

您可以通过调用接受StringComparison类型的重载方法来忽略case：

int index = Required_Ext.IndexOf(
                selected_ext, StringComparison.CurrentCultureIgnoreCase);