If statement - comparing datareader value to datetime

Question

I'm hoping you guys can help with a little issue I'm having. I'm getting some errors when trying to check whether a datareader value is less than a specified dateTime value and need some help.

DateTime feedate = new DateTime(2013,09,01);
if (rsData["M_Start"] != DBNull.Value) & (Convert.ToDateTime(rsData["M_Start"]).ToString("yyyy/mm/dd") < feedate)

So the above is what I have and the errors I'm getting is the 'only assignment call increment decrement and new object expressions can be used as a statement' message.

I'm a bit stumped as C# is still really new to me so any help is appreciated!

Thanks.

Answer 1

1. You should use the logical and && instead
2. You should use DataReader.IsDBNull instead
3. You should not compare a DateTime with a String , why do you convert it to string at all?

---

DateTime feedate = new DateTime(2013, 09, 01);
if (!rsData.IsDBNull(rsData.GetOrdinal("M_Start")) && (DateTime)rsData["M_Start"] < feedate)
{
    // ...
}

Answer 2

You have wrong parenthesis and 'and' operator. The code should read:

DateTime feedate = new DateTime(2013,09,01);
if (rsData["M_Start"] != DBNull.Value && Convert.ToDateTime(rsData["M_Start"]).ToString("yyyy/mm/dd") < feedate)
{
    // code
}

The & operator is a bit-wise or, while the && operator is a logical or. The if statement takes a condition in parenthesis like this: if (… condition goes here …) .

Note: As Tim Schmelter noted in his answer, there are several other flaws, too.