Resolve the Error Object cannot be cast from DBNull to other Types

This code snippet show how to Resolve the Error Object cannot be cast from DBNull to other Types.

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.