C# WebDAV传输大文件时如何避免内存溢出

在C#中，使用WebDAV传输大文件时，为了避免内存溢出，可以采用以下方法：

1. 分块传输：将大文件分成较小的数据块，然后逐个上传。这样可以避免一次性加载整个文件到内存中。

private const int ChunkSize = 4096; // 4KB

public async Task UploadLargeFileAsync(string filePath, string uploadUrl)
{
    using (var fileStream = File.OpenRead(filePath))
    {
        var buffer = new byte[ChunkSize];
        int bytesRead;
        long totalBytesRead = 0;

        while ((bytesRead = await fileStream.ReadAsync(buffer, 0, buffer.Length)) > 0)
        {
            // 上传数据块到WebDAV服务器
            await UploadChunkAsync(uploadUrl, buffer, bytesRead, totalBytesRead);
            totalBytesRead += bytesRead;
        }
    }
}

private async Task UploadChunkAsync(string uploadUrl, byte[] chunk, int chunkSize, long startPosition)
{
    using (var client = new HttpClient())
    {
        var request = new HttpRequestMessage(HttpMethod.Put, uploadUrl);
        request.Headers.Add("Content-Range", $"bytes {startPosition}-{startPosition + chunkSize - 1}/{chunkSize}");
        request.Content = new ByteArrayContent(chunk, 0, chunkSize);

        var response = await client.SendAsync(request);
        response.EnsureSuccessStatusCode();
    }
}

2. 使用流式传输：使用流式传输可以在读取文件的同时进行上传，而不需要将整个文件加载到内存中。

public async Task UploadLargeFileAsync(string filePath, string uploadUrl)
{
    using (var fileStream = File.OpenRead(filePath))
    {
        using (var client = new HttpClient())
        {
            var content = new StreamContent(fileStream);
            var response = await client.PutAsync(uploadUrl, content);
            response.EnsureSuccessStatusCode();
        }
    }
}

3. 调整缓冲区大小：在使用HttpClient发送请求时，可以通过设置HttpClientHandler.MaxRequestContentBufferSize属性来调整缓冲区大小。这将限制HttpClient在发送请求时所使用的内存。

public async Task UploadLargeFileAsync(string filePath, string uploadUrl)
{
    using (var fileStream = File.OpenRead(filePath))
    {
        using (var handler = new HttpClientHandler())
        {
            handler.MaxRequestContentBufferSize = ChunkSize;

            using (var client = new HttpClient(handler))
            {
                var content = new StreamContent(fileStream);
                var response = await client.PutAsync(uploadUrl, content);
                response.EnsureSuccessStatusCode();
            }
        }
    }
}

通过以上方法，可以有效地避免在使用C# WebDAV传输大文件时出现内存溢出的问题。