DataTable to Datagridview

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C#

I have a win form application and my datagrid does not want to fill.
My tabelname is called OPENINGHOURS.

The error message I receive is:

What do I have to set in the formload of my GUI to get those openinghours?

DAL:
++++

public static DataTable GetOpeningHoursFromBranch(string branchname)
{
    try
    {

        int brid = BranchDAL.GetBranchID(branchname);

        string sql = "SELECT * FROM OPENINGHOURS WHERE BranchId=@brid";

        CommandParameterList localparams = new CommandParameterList();

        localparams.Add(new CommandParameter("@brid", brid, DbParameterTypes.Int32, ParameterDirection.Input));

        localDAC.LocalParameters = localparams;

        return localDAC.ExecuteDT(sql, AssignmentTypes.SqlStatement, "OPENINGHOURS");
    }
    catch (SQLDacException ex)
    {
        throw new BranchDALException(ex.Message);
    }
    catch (Exception ex)
    {
        throw new BranchDALException(ex.Message);
    }
}

BLL
++++

public static DataTable GetOpeningHoursFromBranch(string branchname)
  {
      try
      {
          return BranchDAL.GetOpeningHoursFromBranch(branchname);
      }
      catch (BranchDALException ex)
      {
          throw new BranchBLLException(ex.Message);
      }
      catch (Exception ex)
      {
          throw new BranchBLLException(ex.Message);
      }
  }