Error! 'Object cannot be cast from DBNull to other types.' C# with method sum()

Question

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1. Code is error

sum1 = Convert.ToInt32(dtt.Compute("Sum(BIN1)",string.Empty));

2. how can I display on Listbox and just show columns name.

Answer 1

1.public static object DBNullValueorIntIfNotNull(int value)
    {
        object o;
        if (value <= 0)
        {
            o = 0;
        }
        else
        {
            o = value;
        }
        return o;
    }

2.if(sum1 == 0) { columns name.visibale = false;}