Unable to cast object of type 'System.DBNull' to type 'System.String'
We get this error in the following situation.
When database object returns NULL, "DBNULL", and we try to typecast the result.
In the above example, you can see, the reader["name"] is returning NULL.
When we try to typecast to string, we get this error.
We should check whether the database object is NULL before typecasting.
In the above code, we check whether reader["DBCOLUMN"] is NULL or not.
After DBNULL check, we can typecast as per our requirement.
By this way we can resolve this issue.