Handling DBNull and null in ASP.NET

Question

What is the best way of rewriting these (erroneous) lines?

bool? result = dr["result"] == DBNull.Value ? null : Convert.ToInt32(dr["result"]);

...and...

dr["result"] = result ?? DBNull.Value;

Both do not compile.

I am using the MySql connector and it doesn't let me set, for example, dr["result"] = null; which is what I first tried.

Is there an more suitable .NET data type for representing a MySql nullable tinyint(1)?

DeCaf · Accepted Answer · 2011-09-10 17:48:00Z

2

How about:

     dr["Hello"] = (object)result ?? DBNull.Value;
     bool? result = dr["result"] == DBNull.Value ? null : (bool?)(Convert.ToInt32(dr["result"]) != 0);

The reason your suggestion does not compile is that both alternatives of the ternary operator ?: must have the same type. DBNull.Value obviously is not the same type as a bool?. Casting the bool? to an object however makes them both the same type. Similar rules apply on the second row.

answered Sep 10, 2011 at 17:48

DeCaf

6,1461 gold badge31 silver badges51 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

marc_s · Accepted Answer · 2016-02-09 09:57:15Z

-1

If you are using a stored procedure or SQL queries then you can use ISNULL() function of SQL to handle NULL...

edited Feb 9, 2016 at 9:57

marc_s

760k186 gold badges1.4k silver badges1.5k bronze badges

answered Sep 10, 2011 at 17:50

Gaurav Agrawal

4,44110 gold badges47 silver badges64 bronze badges

Collectives™ on Stack Overflow

Handling DBNull and null in ASP.NET

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related