c# - 如何克服自定义文档属性大小限制

Question

我需要将长(特定于文档)字符串保存到 Excel 文档中。由于 Office.Core.CustomDocumentProperty.value 的长度限制仅为 255 个字符，请告知如何克服此限制，或建议其他在 Excel 文档中存储数据的方法。

(我记得，一个单元格公式只能存储 255 个字符，所以这不是一个可行的解决方案。)

Answer 1

只需将您的值拆分为多个属性即可。这样的事情会起作用。

private static void WriteCustomDocumentProperty(Workbook workbook, string name, string value)
{
    dynamic customDocumentProperties = workbook.CustomDocumentProperties;
    var numParts = value.Length/255 + (value.Length%255 != 0 ? 1 : 0);
    for (var i = 0; i < numParts; ++i)
    {
        var part = value.Substring(i*255, Math.Min(255, value.Length - i*255));
        customDocumentProperties.Add(name + "." + i, false, MsoDocProperties.msoPropertyTypeString, part);
    }
    customDocumentProperties.Add(name + ".Count", false, MsoDocProperties.msoPropertyTypeNumber, numParts);
}

private static string ReadCustomDocumentProperty(Workbook workbook, string name)
{
    dynamic customDocumentProperties = workbook.CustomDocumentProperties;
    var numParts = Convert.ToInt32(customDocumentProperties[name + ".Count"].Value);
    var value = new StringBuilder();
    for (var i = 0; i < numParts; ++i)
        value.Append(customDocumentProperties[name + "." + i].Value);
    return value.ToString();
}

根据字符串的大小，这可能会很慢。更好的选择可能是使用自定义 XML 部件。 (我强烈建议将命名空间 “urn:custom-storage:XXX” 更改为独特和专有的东西，以免您与使用相同技术编写的其他软件发生冲突。)

private static void WriteCustomDocumentProperty(Workbook workbook, string name, string value)
{
    var ns = "urn:custom-storage:" + name;
    var document = new XDocument(new XElement(XName.Get("custom-storage", ns), value));
    var xmlValue = document.ToString();
    workbook.CustomXMLParts.Add(xmlValue);
}

private static string ReadCustomDocumentProperty(Workbook workbook, string name)
{
    var ns = "urn:custom-storage:" + name;
    var parts = workbook.CustomXMLParts.SelectByNamespace(ns);
    switch (parts.Count)
    {
        case 0:
            return null;
        case 1:
            return XDocument.Parse(parts[1].XML).Root.Value;
        default:
            throw new ApplicationException("Duplicate part in workbook.");
    }
}