如何确定SharePoint SPFolder中是否存在文件

using (SPSite site = new SPSite("http://your-site-url"))
{
    using (SPWeb web = site.OpenWeb())
    {
        SPFolder folder = web.GetFolder("path/to/your/folder");
        SPFileCollection files = folder.Files;
        web.AllowUnsafeUpdates = true;
        foreach (SPFile file in files)
        {
            if (file.Name == "your-file-name")
            {
                // 文件存在
                break;
            }
        }
    }
}

$siteUrl = "http://your-site-url"
$folderPath = "path/to/your/folder"
$fileName = "your-file-name"

$ctx = New-Object Microsoft.SharePoint.Client.ClientContext($siteUrl)
$folder = $ctx.Web.GetFolderByServerRelativeUrl($folderPath)
$files = $folder.Files
$ctx.Load($files)
$ctx.ExecuteQuery()

foreach ($file in $files)
{
    if ($file.Name -eq $fileName)
    {
        Write-Host "文件存在"
        break
    }
}