C# 复制文件，如果更新则覆盖
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Copy file, overwrite if newer
提问by Louis Rhys
In C#.NET, How to copy a file to another location, overwriting the existing file if the source file is newer than the existing file (have a later "Modified date"), and doing noting if the source file is older?
在 C#.NET 中，如何将文件复制到另一个位置，如果源文件比现有文件新（具有较晚的“修改日期”），则覆盖现有文件，并注意源文件是否较旧？
采纳答案by Tim Schmelter
You can use the FileInfoclassand it's properties and methods:
您可以使用FileInfo该类及其属性和方法：
FileInfo file = new FileInfo(path);
string destDir = @"C:\SomeDirectory";
FileInfo destFile = new FileInfo(Path.Combine(destDir, file.Name));
if (destFile.Exists)
{
if (file.LastWriteTime > destFile.LastWriteTime)
{
// now you can safely overwrite it
file.CopyTo(destFile.FullName, true);
}
}
回答by ronen
You can use the FileInfo class:
您可以使用 FileInfo 类：
FileInfo infoOld = new FileInfo("C:\old.txt");
FileInfo infoNew = new FileInfo("C:\new.txt");
if (infoNew.LastWriteTime > infoOld.LastWriteTime)
{
File.Copy(source path,destination path, true) ;
}
回答by JMK
In a batch file, this will work:
在批处理文件中，这将起作用：
XCopy "c:\my directory\source.ext" "c:\my other directory\dest.ext" /d
回答by Joe Johnston
Here is my take on the answer: Copies not moves folder contents. If the target does not exist the code is clearer to read. Technically, creating a fileinfo for a non existent file will have a LastWriteTime of DateTime.Min so it wouldcopy but falls a little short on readability. I hope this tested code helps someone.
这是我对答案的看法：复制不移动文件夹内容。如果目标不存在，则代码更易于阅读。从技术上讲，为不存在的文件创建文件信息将具有 DateTime.Min 的 LastWriteTime，因此它可以复制但在可读性上有点不足。我希望这个经过测试的代码可以帮助某人。
**EDIT: I have updated my source to be much more flexable. Because it was based on this thread I have posted the update here. When using masks subdirs are not created ifthe subfolder does not contain matched files. Certainly a more robust error handler is in your future. :)
**编辑：我已经更新了我的源代码，使其更加灵活。因为它是基于这个线程，所以我在这里发布了更新。使用掩码时，如果子文件夹不包含匹配的文件，则不会创建子目录。当然，更强大的错误处理程序会在您的未来出现。:)
public void CopyFolderContents(string sourceFolder, string destinationFolder)
{
CopyFolderContents(sourceFolder, destinationFolder, "*.*", false, false);
}
public void CopyFolderContents(string sourceFolder, string destinationFolder, string mask)
{
CopyFolderContents(sourceFolder, destinationFolder, mask, false, false);
}
public void CopyFolderContents(string sourceFolder, string destinationFolder, string mask, Boolean createFolders, Boolean recurseFolders)
{
try
{
if (!sourceFolder.EndsWith(@"\")){ sourceFolder += @"\"; }
if (!destinationFolder.EndsWith(@"\")){ destinationFolder += @"\"; }
var exDir = sourceFolder;
var dir = new DirectoryInfo(exDir);
SearchOption so = (recurseFolders ? SearchOption.AllDirectories : SearchOption.TopDirectoryOnly);
foreach (string sourceFile in Directory.GetFiles(dir.ToString(), mask, so))
{
FileInfo srcFile = new FileInfo(sourceFile);
string srcFileName = srcFile.Name;
// Create a destination that matches the source structure
FileInfo destFile = new FileInfo(destinationFolder + srcFile.FullName.Replace(sourceFolder, ""));
if (!Directory.Exists(destFile.DirectoryName ) && createFolders)
{
Directory.CreateDirectory(destFile.DirectoryName);
}
if (srcFile.LastWriteTime > destFile.LastWriteTime || !destFile.Exists)
{
File.Copy(srcFile.FullName, destFile.FullName, true);
}
}
}
catch (Exception ex)
{
System.Diagnostics.Debug.WriteLine(ex.Message + Environment.NewLine + Environment.NewLine + ex.StackTrace);
}
}
