ProcessBatchUpdate不更新文档库

我有一个正在开发的应用程序，它使用Event接收器将元数据传播到文档库。我正在尝试使用SPWeb。ProcessBatchUpdate将元数据复制回来。我的代码是这样的:

 public string UpdateClosingBookDocuments(SPWeb web, SPList closingBooksDocuments, SPListItemCollection items, SPListItem sourceListItem)
    {
        StringBuilder batchDataStringBuilder = new StringBuilder("<?xml version='"1.0'" encoding='"UTF-8'"?><ows:Batch OnError='"Return'">");
        //string command = generateCommand(closingBooksDocuments.ID, sourceListItem, "urn:schemas-microsoft-com:office:office#");
        string command = generateCommand(closingBooksDocuments.ID, sourceListItem, null);
        foreach (SPListItem item in items)
        {
            batchDataStringBuilder.AppendFormat(command, item["ID"]);
        }
        batchDataStringBuilder.Append("</ows:Batch>");
        web.AllowUnsafeUpdates = true;
        return web.ProcessBatchData(batchDataStringBuilder.ToString());
    }
    private string generateCommand(Guid ID, SPListItem sourceListItem, string varNameSpace)
    {
        StringBuilder commandBuilder = new StringBuilder("<Method ID='"{0}'"><SetList>");
        commandBuilder.Append(ID.ToString());
        commandBuilder.Append("</SetList>");
        commandBuilder.Append("<SetVar Name='"Cmd'">Save</SetVar>");
        commandBuilder.Append("<SetVar Name='"ID'">{0}</SetVar>");
        if (null != sourceListItem["Book Type"])
        {
            commandBuilder.AppendFormat("<SetVar Name='"{1}WilliamsBookType'">{0}</SetVar>", sourceListItem["Book Type"], varNameSpace);
        }
        if (null != sourceListItem["Matter Number"])
        {
            commandBuilder.AppendFormat("<SetVar Name='"{1}WilliamsMatterNumber'">{0}</SetVar>", sourceListItem["Matter Number"], varNameSpace);
        }
        if (null != sourceListItem["Matter Name"])
        {
            commandBuilder.AppendFormat("<SetVar Name='"{1}WilliamsMatterName'">{0}</SetVar>", sourceListItem["Matter Name"], varNameSpace);
        }
        if (null != sourceListItem["Closing Date"])
        {
            commandBuilder.AppendFormat("<SetVar Name='"{1}WilliamsClosingDate'">{0}</SetVar>", sourceListItem["Closing Date"], varNameSpace);
        }
        if (null != sourceListItem["Disposition Date"])
        {
            commandBuilder.AppendFormat("<SetVar Name='"{1}WilliamsDispositionDate'">{0}</SetVar>", sourceListItem["Disposition Date"], varNameSpace);
        }
        if (null != sourceListItem["Principal Williams Party"])
        {
            commandBuilder.AppendFormat("<SetVar Name='"{1}WilliamsPrincipalParty'">{0}</SetVar>", sourceListItem["Principal Williams Party"], varNameSpace);
        }
        if (null != sourceListItem["Principal Counter Party"])
        {
            commandBuilder.AppendFormat("<SetVar Name='"{1}WilliamsCounterParty'">{0}</SetVar>", sourceListItem["Principal Counter Party"], varNameSpace);
        }
        if (null != sourceListItem["Other Parties"])
        {
            commandBuilder.AppendFormat("<SetVar Name='"{1}WilliamsOtherParties'">{0}</SetVar>", sourceListItem["Other Parties"], varNameSpace);
        }
        if (null != sourceListItem["Asset Name"])
        {
            commandBuilder.AppendFormat("<SetVar Name='"{1}WilliamsAssetName'">{0}</SetVar>", sourceListItem["Asset Name"], varNameSpace);
        }
        if (null != sourceListItem["Deal Team"])
        {
            commandBuilder.AppendFormat("<SetVar Name='"{1}WilliamsDealTeam'">{0}</SetVar>", sourceListItem["Deal Team"], varNameSpace);
        }
        if (null != sourceListItem["Legal Department SIC"])
        {
            commandBuilder.AppendFormat("<SetVar Name='"{1}WilliamsLegalDeptSIC'">{0}</SetVar>", sourceListItem["Legal Department SIC"], varNameSpace);
        }
        commandBuilder.Append("</Method>");
        return commandBuilder.ToString();
    }
}

它生成一个CAML片段，看起来像这样:

    <?xml version="1.0" encoding="UTF-8"?>
<ows:Batch OnError="Return">
    <Method ID="1">
        <SetList>c5a3d89c-3f2b-409b-9743-1417db707586</SetList>
        <SetVar Name="Cmd">Save</SetVar>
        <SetVar Name="ID">1</SetVar>
        <SetVar Name="WilliamsBookType">Financings</SetVar>
        <SetVar Name="WilliamsMatterNumber">62626</SetVar>
        <SetVar Name="WilliamsMatterName">Debug Matter</SetVar>
    </Method>
    <Method ID="2">
        <SetList>c5a3d89c-3f2b-409b-9743-1417db707586</SetList>
        <SetVar Name="Cmd">Save</SetVar>
        <SetVar Name="ID">2</SetVar>
        <SetVar Name="WilliamsBookType">Financings</SetVar>
        <SetVar Name="WilliamsMatterNumber">62626</SetVar>
        <SetVar Name="WilliamsMatterName">Debug Matter</SetVar>
    </Method>
</ows:Batch>

结果如下:

<Results><Result ID='"1'" Code='"0'">'r'n</Result>'n<Result ID='"2'" Code='"0'">'r'n</Result>'n</Results>

文档库中没有任何更新!怎么了?