为什么在将Excel导入c# (WPF)时替换列名中的特定字符

当将Microsoft Excel文件导入c# (WPF)时，列名(列头)中的特定字符将被替换。例如，!变成_, .变成#。如何阻止它?

connectionString:

Provider=Microsoft.ACE.OLEDB.12.0; Data Source="+filePath+";Extended Properties="Excel 8.0;HDR=YES;CharacterSet=65001;";

和方法:

 public DataSet ImportExcel(string fileName)
    {
        tableList = null;
        DataSet ds = new DataSet();
        string connectionString = GetConnectionString(fileName);
        using (OleDbConnection conn = new OleDbConnection(connectionString))
        {
            conn.Open();
            OleDbCommand cmd = new OleDbCommand();
            cmd.Connection = conn;

            // Get all Sheets in Excel File
            DataTable dtSheet = conn.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, null);
            tableList = new string[dtSheet.Rows.Count];
            // Loop through all Sheets to get data
            foreach (DataRow dr in dtSheet.Rows)
            {
                string sheetName = dr["TABLE_NAME"].ToString();
                tableList[dtSheet.Rows.IndexOf(dr)] = sheetName;
                Console.WriteLine("TABLE_NAME: " + sheetName);
                if (!sheetName.EndsWith("$"))
                    continue;
                // Get all rows from the Sheet
                cmd.CommandText = "SELECT * FROM [" + sheetName + "]";
                DataTable dt = new DataTable();
                dt.TableName = sheetName;
                OleDbDataAdapter da = new OleDbDataAdapter(cmd);
                da.Fill(dt);
                rowsCount += dt.Rows.Count;
                ds.Tables.Add(dt);
            }
            cmd = null;
            conn.Close();
        }
        return ds;
    }