1. 首先，创建一个报告模板并将其保存为PXReport.xml文件。确保该文件位于App_Data/Reports路径下。

2. 接下来，在电子邮件发送事件中，读取报告模板并生成报告。

protected void SOInvoice_RowInserted(PXCache sender, PXRowInsertedEventArgs e)
{
    var doc = (ARInvoice)e.Row;
    var reportID = "CUSTOM_REPORT";
    var parameters = new Dictionary
    {
        ["InvoiceID"] = doc.DocType,
        ["InvoiceType"] = doc.DocType
    };

    var reportNode = GetReportNode(reportID);
    using (var report = PXReportTools.LoadReport(reportNode, null))
    {
        PXReportTools.InitReportParameters(report, parameters, PXSettingProvider.Instance.Default);
        var result = PXReportTools.RenderReport(report, null, PXSettingProvider.Instance.Default);
        var attachment = new PX.SM.FileInfo($"ARInvoice-{doc.RefNbr}.pdf", null, result.First);
        attachment.Data = result.Second;
        bool alwaysAttachReport = true; //set this to false if you only want to attach the report if certain conditions are met

        if (alwaysAttachReport || /* insert condition here */)
        {
            PXNoteAttribute.SetFileNotes(SOInvoice.Cache, e.Row, new[] { attachment });
            sender.Graph.MailSend.AddAttachment(attachment);
        }
    }
}

private XmlNode GetReportNode(string reportID)
{
    var app = PX.Common.PXInstanceHelper.Current;
    var resolver = (PX.Data.Processing.PXFileResolver)app.GetService(typeof(PX.Data.Processing.IPXFileResolver));
    var node = PX.Data.PXReportsMaint.LoadReport(reportID, app, resolver);
    return node;
}

3. 最后，将报告添加为电子邮件附件：

sender.Graph.MailSend.AddAttachment(attachment);

注意：上述代码仅适用于添加单个报告至附件。如果需要添加多个报告，可以将attachment变量复制到一个列表中并在电子邮件发送事件结束时循环遍历。