c# - 设置 Artist 字段时 Taglib 数组异常

Question

在编辑 ID3 数据的函数中，我不断收到 Taglib.tag.Performers 的数组越界异常。我在其他地方读到清除 tag.performers[] 可以提供帮助(如果为空)，但有时我仍然会收到错误。

错误消息:

"Index was outside the bounds of the array.Data:

'System.Collections.ListDictionaryInternal' for test.mp3"

var fileArr = Directory.GetFiles(BasePath, "*.*", SearchOption.AllDirectories).Where(s => s.EndsWith(".mp3") || s.EndsWith(".m4a")).ToArray();

foreach (var file in fileArr)
{
    string fileName = Path.GetFileName(file);
    string tagArtist = "";
    string tagTitle = "";
    string tempRegFilename = fileName;
    string title = "";

    //Apply to tag
    TagLib.File mp3tag = TagLib.File.Create(file);

    if (mp3tag.Tag.Title != null && mp3tag.Tag.Title.Length > 1)
    {
        title = mp3tag.Tag.Title;
    } 
    else
    {
        mp3tag.Tag.Title = String.Empty;
    }

    if (mp3tag.Tag.Performers[0].Length < 1 || mp3tag.Tag.Performers[0] == null)
    {
        mp3tag.Tag.Performers[0] = null;
        mp3tag.Tag.Performers = new[] { String.Empty };
        mp3tag.Save();
    }

    if (mp3tag.Tag.Performers[0].Length > 1)
    {
        string[] performers = mp3tag.Tag.Performers;
        if (title.Length > 2 && performers[0].Length > 1)
        {
            tagTitle = title;
            tagArtist = performers[0].ToString();
            Log.Info("ID3 Artist: " + "[" + tagArtist + "]");
            Log.Info("ID3 Title: " + "[" + tagTitle + "]");
            Log.Info("Tag data OK");
        }
    }
    //Get artist from filename
    if (mp3tag.Tag.Performers[0].Length < 1 || mp3tag.Tag.Performers == null)
    {
        mp3tag.Tag.Performers = new[] { String.Empty };
        string prevArtist = String.Empty;

        if (tempRegFilename.Contains("-"))
        {
            Log.Info("Artist data missing...");
            string[] words = tempRegFilename.Split('-');
            {
                words[0] = words[0].Trim();
                string perf = words[0];
                mp3tag.Tag.Performers = new[] { perf };
                Log.Info("Artists changed from \'" + prevArtist + "\' to " + "'" + perf + "'" + "\r\n");
                mp3tag.Save();
            }
        }
        mp3tag.Save();
    }
}

catch (Exception ex)
{
    Log.Error("TAG EXCEPTION: " + ex.Message + "Data: " + "'" + ex.Data + "'" + " for " + fileName + "\r\n" + ex.HelpLink);
}

谁能看出哪里出了问题吗？我没有太多经验，可以使用帮助。谢谢。

Answer 1

您似乎在很多地方都假设 mp3Tag.Tag.Performers 中至少有一个元素。如果没有，那么每当您尝试访问 mp3tag.Tag.Performers[0]

时，您都会遇到您提到的异常

看起来您可能正在尝试使用以下代码来捕捉这种可能性:

if (mp3tag.Tag.Performers[0].Length < 1 || mp3tag.Tag.Performers[0] == null)
{
    mp3tag.Tag.Performers[0] = null;
    mp3tag.Tag.Performers = new[] { String.Empty };
    mp3tag.Save();
}

但是你的逻辑是不正确的:你从数组中获取第一个元素(显然是一个字符串)并检查其长度，而不是检查数组的长度数组本身。试试这个:

if (mp3tag.Tag.Performers.Length < 1 || mp3tag.Tag.Performers[0] == null)
{
    mp3tag.Tag.Performers = new[] { String.Empty };
    mp3tag.Save();
}

PS:如果您的日志包含异常的堆栈跟踪，而不仅仅是其消息，那么您会更容易看到错误所在。我通常发现最好只对异常本身使用 ToString()。