我无法更改TFS工作区

using Microsoft.TeamFoundation.Client;
using Microsoft.TeamFoundation.VersionControl.Client;

public void UnlockWorkspace(string workspaceName)
{
    TfsTeamProjectCollection tfs = new TfsTeamProjectCollection(new Uri("http://your-tfs-server:8080/tfs"));
    VersionControlServer vcs = tfs.GetService<VersionControlServer>();

    Workspace workspace = null;
    foreach (Workspace ws in vcs.Workspaces)
    {
        if (ws.Name == workspaceName)
        {
            workspace = ws;
            break;
        }
    }

    if (workspace != null)
    {
        workspace.Unlock(null, "Unlocking workspace via API");
        Console.WriteLine("Workspace unlocked successfully.");
    }
    else
    {
        Console.WriteLine("Workspace not found.");
    }
}