C# WinForm 实现文件的拖入和拖出(拖拽操作)
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本文通过五个步骤详细介绍C# WinForm 实现文件的拖入和拖出(拖拽操作),每个步骤都提供相关的示例代码供参考。
步骤1、放置一个 ListView 到 Winform窗体中 并初始化如下属性:- listView.View = View.Details;
- listView.AllowDrop = true;
步骤2、撰写一个目录文件列表显示的函数 -
-
-
-
- private void ListFolder(string directory)
- {
- labelCurFolder.Text = directory;
-
- String[] fileList = System.IO.Directory.GetFiles(directory);
- listViewFolder.Items.Clear();
- listViewFolder.Columns.Clear();
- listViewFolder.Columns.Add(" Name ", 300);
- listViewFolder.Columns.Add(" Size ", 100);
- listViewFolder.Columns.Add(" Time ", 200);
-
- foreach (string fileName in fileList)
- {
-
- ListViewItem itemName = new ListViewItem(System.IO.Path.GetFileName(fileName));
- itemName.Tag = fileName;
-
-
-
- IconImageProvider iconImageProvider = new IconImageProvider(listViewFolder.SmallImageList, listViewFolder.LargeImageList);
-
- itemName.ImageIndex = iconImageProvider.GetIconImageIndex(fileName);
-
-
- System.IO.FileInfo fileInfo = new System.IO.FileInfo(fileName);
- long size = fileInfo.Length;
-
- String strSize;
- if (size < 1024)
- {
- strSize = size.ToString();
- }
- else if (size < 1024 * 1024)
- {
- strSize = String.Format(" {0:###.##}KB ", (float)size / 1024);
- }
- else if (size < 1024 * 1024 * 1024)
- {
- strSize = String.Format(" {0:###.##}MB ", (float)size / (1024 * 1024));
- }
- else
- {
- strSize = String.Format(" {0:###.##}GB ", (float)size / (1024 * 1024 * 1024));
- }
-
- ListViewItem.ListViewSubItem subItem = new ListViewItem.ListViewSubItem();
- subItem.Text = strSize;
- subItem.Tag = size;
- itemName.SubItems.Add(subItem);
-
-
- subItem = new ListViewItem.ListViewSubItem();
- DateTime fileTime = System.IO.File.GetLastWriteTime(fileName);
-
- subItem.Text = (string)fileTime.ToLocalTime().ToString(" yyyy-MM-dd HH:mm:ss "); ;
- subItem.Tag = fileTime;
-
- itemName.SubItems.Add(subItem);
- listViewFolder.Items.Add(itemName);
- }
- }
上面代码中有一段显示图标的代码由于和拖动无关,我就不贴出来了,感兴趣可以下载完整的代码去看。步骤3、为ListView 添加 DragEnter 事件- private void listViewFolder_DragEnter(object sender, DragEventArgs e)
- {
- if (e.Data.GetDataPresent(DataFormats.FileDrop))
- {
- e.Effect = DragDropEffects.Copy;
- }
- else
- {
- e.Effect = DragDropEffects.None;
- }
- }
DragEnter 事件在其他应用程序拖入的文件进入时判断当前拖动的对象类型,如果是文件类型,则设置拖动响应类型为Copy。步骤4、为ListView 添加 DragDrop 事件 - private void listViewFolder_DragDrop(object sender, DragEventArgs e)
- {
- try
- {
- String[] files = e.Data.GetData(DataFormats.FileDrop, false) as String[];
-
-
- foreach (string srcfile in files)
- {
- string destFile = labelCurFolder.Text + " \\ " + System.IO.Path.GetFileName(srcfile);
- if (System.IO.File.Exists(destFile))
- {
- if (MessageBox.Show(string.Format(
- " This folder already contains a file named {0}," +
- "would you like to replace the existing file ",
- System.IO.Path.GetFileName(srcfile)),
- " Confirm File Replace ",
- MessageBoxButtons.YesNo,
- MessageBoxIcon.None) != DialogResult.Yes)
- {
- continue;
- }
- }
-
- System.IO.File.Copy(srcfile, destFile, true);
- }
-
-
- ListFolder();
- }
- catch (Exception e1)
- {
- MessageBox.Show(e1.Message, " Error ",
- MessageBoxButtons.OK, MessageBoxIcon.Error);
- }
- }
DragDrop 事件在这里完成将其他应用程序拖入的文件拷贝到Winform应用当前的目录中。完成上述4步后,拖入功能就实现了,下面步骤完成拖出功能。步骤5、为ListView 添加 ItemDrag 事件 - private void listViewFolder_ItemDrag(object sender, ItemDragEventArgs e)
- {
- if (e.Button == MouseButtons.Left)
- {
- if (listViewFolder.SelectedItems.Count <= 0)
- {
- return;
- }
-
-
- string[] files = new String[listViewFolder.SelectedItems.Count];
-
- int i = 0;
- foreach (ListViewItem item in listViewFolder.SelectedItems)
- {
- files[i++] = item.Tag.ToString();
- }
-
-
- DataObject data = new DataObject(DataFormats.FileDrop, files);
-
-
- data.SetData(DataFormats.StringFormat, files[0]);
-
-
- DoDragDrop(data, DragDropEffects.Copy);
- }
- }
这个事件在ListView 的Item被拖动时响应,我们利用这个事件将当前选中的item对应的文件名复制到拖动数据中,并调用窗体的DoDragDrop方法告知窗体现在开始做拖放操作。通过以上5个步骤,C# WinForm程序的文件拖拽操作功能就可以实现了。