How to copy files into a directory in C#?

To copy files in C#, the File.Copy method is the primary approach. This method allows you to copy individual files from one location to another, with options to control whether existing files should be overwritten.

Syntax

The File.Copy method has two overloads −

File.Copy(string sourceFileName, string destFileName)

File.Copy(string sourceFileName, string destFileName, bool overwrite)

Parameters

• sourceFileName − The file to copy.

• destFileName − The name of the destination file. This cannot be a directory.

• overwrite − true if the destination file should be overwritten if it already exists; otherwise, false.

Copy Methods Comparison

Using Directory.GetFiles for Multiple Files

To copy multiple files, combine Directory.GetFiles with File.Copy. The Directory.GetFiles method returns file paths that match specified patterns −

Directory.GetFiles(string path, string searchPattern, SearchOption searchOption)

Example − Copying Multiple Files

using System;
using System.IO;

class Program {
    static void Main(string[] args) {
        // Create test directories and files
        string sourceDir = @"C:\temp\source";
        string destDir = @"C:\temp\destination";
        
        Directory.CreateDirectory(sourceDir);
        Directory.CreateDirectory(destDir);
        
        // Create sample files
        File.WriteAllText(Path.Combine(sourceDir, "file1.txt"), "Content of file 1");
        File.WriteAllText(Path.Combine(sourceDir, "file2.txt"), "Content of file 2");
        File.WriteAllText(Path.Combine(destDir, "existing.txt"), "Existing file");

        Console.WriteLine("-------------Source Folder-------------");
        string[] sourceFiles = Directory.GetFiles(sourceDir, "*.*", SearchOption.TopDirectoryOnly);
        foreach (string file in sourceFiles) {
            Console.WriteLine(Path.GetFileName(file));
        }

        Console.WriteLine("
-------------Destination Folder Before Copying-------------");
        string[] destFilesBefore = Directory.GetFiles(destDir, "*.*", SearchOption.TopDirectoryOnly);
        foreach (string file in destFilesBefore) {
            Console.WriteLine(Path.GetFileName(file));
        }

        // Copy all files from source to destination
        foreach (string file in sourceFiles) {
            string fileName = Path.GetFileName(file);
            string destPath = Path.Combine(destDir, fileName);
            File.Copy(file, destPath, true); // true allows overwriting
        }

        Console.WriteLine("
-------------Destination Folder After Copying-------------");
        string[] destFilesAfter = Directory.GetFiles(destDir, "*.*", SearchOption.TopDirectoryOnly);
        foreach (string file in destFilesAfter) {
            Console.WriteLine(Path.GetFileName(file));
        }
    }
}

The output of the above code is −

-------------Source Folder-------------
file1.txt
file2.txt

-------------Destination Folder Before Copying-------------
existing.txt

-------------Destination Folder After Copying-------------
existing.txt
file1.txt
file2.txt

Using File.Copy with Error Handling

Example − Safe File Copying

using System;
using System.IO;

class Program {
    static void Main(string[] args) {
        // Create test setup
        string sourceDir = @"C:\temp\test_source";
        string destDir = @"C:\temp\test_dest";
        
        Directory.CreateDirectory(sourceDir);
        Directory.CreateDirectory(destDir);
        
        string sourceFile = Path.Combine(sourceDir, "document.txt");
        File.WriteAllText(sourceFile, "Important document content");

        string destFile = Path.Combine(destDir, "document_copy.txt");

        try {
            // Copy without overwrite
            File.Copy(sourceFile, destFile, false);
            Console.WriteLine("File copied successfully to: " + destFile);
            
            // Attempt to copy again without overwrite - will throw exception
            File.Copy(sourceFile, destFile, false);
        }
        catch (IOException ex) {
            Console.WriteLine("Copy failed: " + ex.Message);
            
            // Copy with overwrite allowed
            File.Copy(sourceFile, destFile, true);
            Console.WriteLine("File copied with overwrite enabled");
        }
        catch (Exception ex) {
            Console.WriteLine("Unexpected error: " + ex.Message);
        }
    }
}

The output of the above code is −

File copied successfully to: C:\temp\test_dest\document_copy.txt
Copy failed: The file 'C:\temp\test_dest\document_copy.txt' already exists.
File copied with overwrite enabled

Conclusion

The File.Copy method in C# provides a straightforward way to copy files, with the boolean overload offering control over existing file behavior. When copying multiple files, combine it with Directory.GetFiles and always include proper exception handling for robust file operations.