删除附件SAP B1时出错9

Question

我成功添加了文件和多文件，但是当我要删除文件时出现-5002错误，我无法理解我在哪里做错了？ 我的代码在这里：

SAPbobsCOM.Attachments2 oatt2 = (SAPbobsCOM.Attachments2)Program.oCompany.GetBusinessObject(SAPbobsCOM.BoObjectTypes.oAttachments2);
int d;
string value2 = EditText16.Value;
if (int.TryParse(value2, out d) && d > 0)
{
    oatt2.GetByKey(d);

    for (int i = 1; i < Matrix1.RowCount; i++)
    {
        if (Matrix1.IsRowSelected(i) == true)
        {
            // var line = Convert.ToInt32(((SAPbouiCOM.EditText)this.Matrix1.Columns.Item(0).Cells.Item(i).Specific).Value);
            // int lineint =   Convert.ToInt32(line)
            // oatt2.Lines.SetCurrentLine(i);
            // oatt2.Lines.Override = SAPbobsCOM.BoYesNoEnum.tYES;
            oatt2.Lines.SourcePath = "";
            oatt2.Lines.FileName = "";
            oatt2.Lines.FileExtension = "";
            // oatt2.Add();
            int retval = oatt2.Update();

            int a = Program.oCompany.GetLastErrorCode();
            string err = Program.oCompany.GetLastErrorDescription();
            if (a != 0)
            {
                SAPbouiCOM.Framework.Application.SBO_Application.MessageBox(err);
            }
        }
    }
}