简单账表如何获取过滤条件基础资料名称到表头文本字段

开发了一个简单账表，表头有供应商文本字段，过滤界面有供应商基础资料字段。在插件里写如下代码获取的是object类型，取不到供应商名称，应该怎么做？
public override ReportTitles GetReportTitles(IRptParams filter)
{
var result = base.GetReportTitles(filter);
DynamicObject dyFilter = filter.FilterParameter.CustomFilter;
string d = filter.FilterParameter.FilterString;
if (dyFilter != null)
{
if (result == null)
{
result = new ReportTitles();
}
result.AddTitle("F_PAEZ_GYS", Convert.ToString(dyFilter["BeginSupplierId"]));
result.AddTitle("F_PAEZ_GCXM", Convert.ToString(dyFilter["F_PAEZ_GCXM"]));
result.AddTitle("F_PAEZ_BM", Convert.ToString(dyFilter["F_PAEZ_BM"]));
result.AddTitle("F_PAEZ_WL", Convert.ToString(dyFilter["F_PAEZ_WL"]));

}
return result;
}