exception data type

I have a simple methid in which I am getting records from view based on semester_ID like below

public int Get_semesterCode(long semID)

{

var findCode=(from nn in db.SemesterView where vv.semesterId==semID.Tostring() select vv).firstOrDefault();

}

you can see my semID is long and the semesterId coming from view is having varchar(40) as type . I cannot change this long to string as it is requirement that the parameter semID must be long so how to compare , as work around i wrote a simple line like below

string semesid=semID.ToString()

it have value collected and converted to string and semesid get the value but after that when the below code runs it gives exception

var findCode=(from nn in db.SemesterView where vv.semesterId==semID.Tostring() select vv).firstOrDefault();

}

The exception you are encountering is likely due to a type mismatch between the data types of semID and semesterId in the database. Since semID is a long and semesterId is a varchar(40), the comparison between the two will fail because they are not of the same type.

To avoid this issue, you can convert the semesterId value to a long before comparing it to semID. One way to do this is by using the long.TryParse method:

public int Get_semesterCode(long semID)
{
    long semesterId;
    if (long.TryParse(semID.ToString(), out semesterId))
    {
        var findCode = (from nn in db.SemesterView
                        where nn.semesterId == semesterId
                        select nn).FirstOrDefault();
        if (findCode != null)
        {
            // do something with findCode
        }
        else
        {
            // handle the case where no record is found
        }
    }
    else
    {
        // handle the case where semID cannot be parsed to a long
    }
}

Thanks