reading null values in dataset

monika

18y7.9k

I have to read a database using dataset. My database has some null values.
My code is working fine when there is a value in the database. But when there is a null value in the database, dataset throws an exception.

I have to read null value in a variable. I have tried this....

if (dr["value"] != DBNull.Value)
                    {
                        abc = Convert.ToDouble(dr["value"]);
                        MessageBox.Show("value is:" + abc.ToString());
                     }
                    else
                    {
                      abc=null;
                      MessageBox.Show("value is:" + abc.ToString());
                    }

But it gives an error that null can not be assigned to a double variable(here abc is a double variable). How can I read a null value in a variable.
Can anybody guide me....

2 Replies

Know the answer? Post it — somebody with the same question will find it here.

Mahesh Deo18y ago
Try following code. While you declare abc variable declare it as follows. dosing this will not give error you can assign null value to your int32 variables also. please change Int23 to your type Use generic nullable class. this editor is not allowing me to wrote correct syntax Nullable abc=null; MessageBox.Show(abc.ToString()); abc=23; MessageBox.Show(abc.ToString());
Blocked Account18y ago
Hi Monika,
If u know that else part executes when null value comes.
then u can do that as follow, in the else part.

string abc = "";

MessageBox.Show("value is:" + abc);

another work u can do , u can set any default value in the field which contains the null value by using the case statement in the stored procedure and check in the page.