libgit2sharp无法仅将文件提交到特定分支。需要帮助

using LibGit2Sharp;

public class GitHelper
{
    public void CommitFileToBranch(string repositoryPath, string branchName, string filePath, string authorName, string authorEmail, string commitMessage)
    {
        using (var repo = new Repository(repositoryPath))
        {
            // 切换到目标分支
            var branch = repo.Branches[branchName];
            Commands.Checkout(repo, branch);

            // 将文件添加到暂存区
            repo.Index.Stage(filePath);

            // 提交文件
            var author = new Signature(authorName, authorEmail, DateTimeOffset.Now);
            var committer = author;
            var commitOptions = new CommitOptions { AllowEmptyCommit = false };
            repo.Commit(commitMessage, author, committer, commitOptions);
        }
    }
}