what is the issue in the code

DataColumn dc1 = new DataColumn("SubjectText",System.Type.GetType("System.String"));
                            
                            DataColumn dc2 = new DataColumn("SubjectID", System.Type.GetType("System.String"));
                            DataTable dt = new DataTable();
                            dt.Columns.Add(dc1);
                            dt.Columns.Add(dc2);

                            DataRow dr = dt.NewRow();

                            dr["SubjectID"] = "net20";

                            dr["SubjectText"] = DBNull.Value;

                            dt.Rows.Add(dr);

                            foreach (DataRow dr1 in dt.Rows)
                            {                                
                                Console.WriteLine(dr1["SubjectText"]);
                            }

Open in new window


If you look at the table while debugging the application blank is coming instead of null. Why


Regards
Karan Gupta
KaranGuptaAsked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

SwapnilSoftware ArchitectCommented:
Hi KaranGupta,

Use  SqlString.Nul instead of DBNull.Value like below.

 dr["SubjectText"] = SqlString.Null;

Thanks,
NetSwap.
0
SwapnilSoftware ArchitectCommented:
add following to use the SqlString type.

using System.Data.SqlTypes;

Thanks,
NetSwap.
0
KaranGuptaAuthor Commented:
Hi netswap

see this code

DataColumn dc1 = new DataColumn("SubjectText", System.Type.GetType("System.String"));

            DataColumn dc2 = new DataColumn("SubjectID", System.Type.GetType("System.String"));
            DataTable dt = new DataTable();
            dt.Columns.Add(dc1);
            dt.Columns.Add(dc2);

            DataRow dr = dt.NewRow();

            dr["SubjectID"] = "net20";

            dr["SubjectText"] = SqlString.Null;

            dt.Rows.Add(dr);

            foreach (DataRow dr1 in dt.Rows)
            {
                if (Convert.IsDBNull(dr1["SubjectText"]))
                {
                    Console.WriteLine("dbnull");
                }
            }

Open in new window


Here dbnull is not displaying so SqlString.Null is not dbnull

Regards
Karan Gupta
0
nishant joshiTechnology Development ConsultantCommented:
check code and find nullls....:-D


Regards,
nishant
DataColumn dc1 = new DataColumn("SubjectText", System.Type.GetType("System.String"));
       DataColumn dc2 = new DataColumn("SubjectID", System.Type.GetType("System.String"));
       DataTable dt = new DataTable();
       dt.Columns.Add(dc1);
       dt.Columns.Add(dc2);
       DataRow dr = dt.NewRow();
       dr["SubjectID"] = "net20";
       dr["SubjectText"] = null;
       dt.Rows.Add(dr);
       foreach (DataRow dr1 in dt.Rows)
       {
           if (dr1["SubjectText"].GetType() == System.DBNull.Value.GetType())
           {
               Console.Write("found null in value...");
           }
       }

Open in new window

0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
SwapnilSoftware ArchitectCommented:
Hi Karangupta,

      Please find attached image. The original code you were doing is appropriate in your case. DBNull.Value is stored in column properly and its also checked with ISDBNull() function.

Thanks,
Netswap.
EE.JPG
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
.NET Programming

From novice to tech pro — start learning today.

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.