CODEWITHSUNDEEP
c#
priyanka.sarkar
priyanka.sarkar

Reputation: 26518

any way to convert from DB.Null to decimal in C#

Is there any way to convert from DB.Null to decimal in C#?

Like 

Object[] returnvalue = new Object[1];
returnvalue[0] = null;
returnvalue[0] = Convert.ToDecimal(returnvalue[returnvalue.Length - 1]);

Though CLR is saying that DBNull.Value cannot be type casted. Still I want to know is there

any work around? Thanks in advance

Upvotes: 2

Views: 33631

Answers (9)

Janus
Janus

Reputation: 1

It could looks like this:

private decimal GetDecimal(string v)
{
    decimal r = 0.00M;

    try {
        r = decimal.Round(Convert.ToDecimal(v.Replace("%", "").Replace("zł", "").Replace(" ", "")), 2);
    }
    catch (Exception ex)
    {
        Debug.WriteLine(ex.Message.ToString());
    }

    return r;
}

Calling:

decimal val = GetDecimal(dataTable.Rows[i][j].ToString()),

Upvotes: 0

Vishav Premlall
Vishav Premlall

Reputation: 494

We use the below method to cast DBNull fields to decimal values in C#. The case where the field might be null can be catered for when giving the value of the field to the variable using a shorthand if.

 cmd.Fill<Entity>(result, a => new Entity()
                {

                    EntityProperty = (decimal)(a["FieldName"] == DBNull.Value ? null : a["FieldName"]),

                });

Upvotes: 0

fsbflavio
fsbflavio

Reputation: 874

You can simply do this:

Object[] returnvalue = new Object[1];
returnvalue[0] = DBNull.Value; //null from database
returnvalue[0] = returnvalue[0] == DBNull.Value 
? null 
: (Nullable<decimal>) Convert.ToDecimal(returnvalue[returnvalue.Length - 1]);

Upvotes: 1

Matthew Scharley
Matthew Scharley

Reputation: 132384

How do you expect to cast null to anything? It's null, nothing, nada...

That said, your best bet would be to check for DBNull (or null in the above case) and use/return/whatever default(decimal) instead, though null and DBNull both have a significant semantic difference from just a default value; they are the absence of a value, so this is probably not what you want to do.

Upvotes: 7

Null Head
Null Head

Reputation: 2941

Would this help?

returnvalue[returnvalue.Length - 1] is DBNull ? 0 : (decimal?)returnvalue[returnvalue.Length - 1] ?? 0

Upvotes: 0

Nikki9696
Nikki9696

Reputation: 6348

        object foo = DBNull.Value;
        decimal d = 0;

        d = (decimal)(foo as decimal? ?? 0); // handles dbnull fine with default 0

        MessageBox.Show(d.ToString());

        foo = 1234M;

        d = (decimal)(foo as decimal? ?? 0); // handles dbnull fine with default 0

        MessageBox.Show(d.ToString());

Upvotes: 4

Bevan
Bevan

Reputation: 44317

Have you considered using a nullable-decimal for your return value?

Though you'd still have to explicitly handle DB.Null, as that's different to null, you'd be able to differentiate the cases.

The code might look something like this ...

if (value == DB.Null)
    return null;
else return decimal.Parse(value.ToString());

Upvotes: 3

Marc Gravell
Marc Gravell

Reputation: 1063403

There is a big difference between DBNull and null; your example only shows null...

But in answer; not really... what value whould you give it?

You could test and use the default, or use Nullable<decimal> (aka decimal?):

With null (not DBNull)

decimal? valOrNull = (decimal?)returnvalue[0];

or to take DBNull into account:

object val = returnvalue[0];
decimal? valOrNull = (val == null || val is DBNull) ? (decimal?)null
            : (decimal?)val; // or convert if it is a string etc

Upvotes: 7

Nippysaurus
Nippysaurus

Reputation: 20378

If DBNull were to be converted to a Decimal, what value would you expect that decimal to have?

I think there is a Decimal.TryParse() function which would fail more gracefully.

Upvotes: 0

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