public string CreateExcelWithRJson(string jsonStr)
{
RM4ExcelData excelData = DataContractHelper.FromJsonTo <RM4ExcelData>(jsonStr);
DataTable exceltable = CreateMyExcel(excelData);
strHeaderText = excelData.Title;
string paths = HttpContext.Current.Server.MapPath("~");
strFileName = paths + "\\upload\\excel";
strHeaderText = GetFieldName(strHeaderText);
string filename = GetFileName(strHeaderText);
strFileName = strFileName + "\\" + filename;
StartCreateExcel(exceltable, strHeaderText, strFileName);
return(filename);
}