To check if a column exists:
dRow.Table.Columns["msisdn"] == nullThe row doesn't contain a column property as such. Therefore you will have to get into the Parent table property to check into the columns in the row.
If the column doesn't exist,
dr["msisdn"] == nullwill throw and error.
To check if a column has value and is not null value:
dr["msisdn"] == DBNull.Valueand
if(dr.IsNull("msisdn"))are used to check if a column has value