Unable to pass empty value to a variable from datatable column

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In a datatable I have a string column 'shipping charges'. In one of the datatable row, this column is empty. I want to pass the values from this column to an int variable 'v_shippingcharges'. I tried with the following code but get error at line 'v_shippingcharges=...' I get the error as: 'Object cannot be cast from DBNull to other types'.

C#

if (dtCurrentTable.Rows[i]["Shipping Charges"] != null)
                   {
                       v_shippingcharges = Convert.ToInt32(dtCurrentTable.Rows[i]["Shipping Charges"]);
                   }
                   else
                   {
                       v_shippingcharges = 0;
                   }

Posted 27-Mar-14 0:48am

S.Rajendran from Coimbatore

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Kornfeld Eliyahu Peter · Answer 1 · 2014-03-27T00:54:00

Solution 1

According to the error the column isn't empty it's NULL - it's not the same...
Your problem is that you try to convert NULL to int which is not nullable type...
You have a few options
1. In SQL do ISNULL(column, 0) - or any other default value
2. In the code do if(Convert.IsDBNull(column)){initialize with some default value} - http://msdn.microsoft.com/en-us/library/system.convert.isdbnull.aspx[^]
3. You may use nullable int in your code - http://msdn.microsoft.com/en-us/library/2cf62fcy.aspx[^]

Posted 27-Mar-14 0:54am

Kornfeld Eliyahu Peter

Updated 27-Mar-14 1:13am

v2

Comments

S.Rajendran from Coimbatore 27-Mar-14 7:11am

If it is null I want to assign v_shhipingcharges=0. This is not happenning. It is not that I want to convert null to int.

Kornfeld Eliyahu Peter 27-Mar-14 7:14am

That because null is not DBNull - you have to use Convert.IsDBNull...

S.Rajendran from Coimbatore 27-Mar-14 7:23am

Is DBNull for dataset or datatable?

Kornfeld Eliyahu Peter 27-Mar-14 7:27am

DBNull is a class (type) - http://msdn.microsoft.com/en-us/library/system.dbnull(v=vs.110).aspx
It used in all the System.Data namespace and other places...