Cannot insert DBNULL value in sql server

Question

Why am I getting this error?

Object cannot be cast from DBNull to other types.

when I entered null for a numeric data type in SQL Server 2005

Here is my code

 if (MeasurementTr.Visible == true)
    {
        materialIn.measurementId = Convert.ToInt64(DlMeasurement.SelectedValue.ToString());
    }
    else
    {
        materialIn.measurementId = Convert.ToInt64(DBNull.Value);
    }

EDIT :

Is it correct?

 materialIn.measurementId = (Convert.ToInt64(DlMeasurement.SelectedValue.ToString()) != 0) ? Convert.ToInt64(DlMeasurement.SelectedValue.ToString()) : 0;

Answer 1

You cannot convert DBNull.Valueto Int64how your code is trying to do in Convert.ToInt64. DBNull.Valuemeans "unknown" or "nonexistent," and therefore there is no logical conversion to any other data type.

materialIn - DataRow, SetMeasurementIdNull, . Linq SQL EF, DBNull, materialIn.measurementId = null.

Answer 2

Object cannot be cast from DBNull to other types.

, DBNull.

materialIn.measurementId = DlMeasurement.SelectedValue == DBNull.Value? 0: Convert.ToInt64 (DlMeasurement.SelectedValue.ToString());

Answer 3

DBNull Int64. nullable int, null - null, 0, .