Object cannot be cast from DBNull to other types for Double Data Type

Question

I am seeing error when there is null value in database for any cell, Object cannot be cast from DBNull to other types. - Asp.net grid view

Answer 1

Reason for the error: In an object-oriented programming language, null means the absence of a reference to an object. DBNull represents an uninitialized variant or nonexistent database column. Source:MSDN

Actual Code which I faced error:

Before changed the code:

        if( ds.Tables[0].Rows[0][0] == null ) //   Which is not working

         {
                seqno  = 1; 
          }
        else
        {
              seqno = Convert.ToInt16(ds.Tables[0].Rows[0][0]) + 1;
         }

After changed the code:

   if( ds.Tables[0].Rows[0][0] == DBNull.Value ) //which is working properly
        {
                    seqno  = 1; 
         }
            else
            {
                  seqno = Convert.ToInt16(ds.Tables[0].Rows[0][0]) + 1;
             }

Conclusion: when the database value return the null value, we recommend to use the DBNull class instead of just specifying as a null like in C# language.