Change Datatable Column Value based on condition - wpf

Question

I have a datatable in which I have datetime column, in Database DateTime is set as null so it fills with default datetime. Now when I view this datatable in WPF it shows me these dates. Where as I want to make it empty if date is less than 2000-01-01.
foreach (DataRow row in table.Rows)
{
if (row["PROCESSED__DATE"].ToString() != "")
{
string s = Convert.ToDateTime(row["PROCESSED__DATE"].ToString()).ToString("MM/dd/yyyy HH:mm:ss");
if (DateTime.ParseExact(s, "MM/dd/yyyy HH:mm:ss", System.Globalization.CultureInfo.InvariantCulture)<
DateTime.ParseExact("01/01/2000 00:00:00", "MM/dd/yyyy
HH:mm:ss",System.Globalization.CultureInfo.InvariantCulture
{
row["PROCESSED__DATE"] = "";
}
}
}
I am using this following code to replace datetime column value to empty but I am getting an error on the following line:
row["PROCESSED__DATE"] = "";
The error is String was not recognized as a valid DateTime.Couldn't store, I know this is causing because I am trying to save empty string in DATETIME column. But what I don't know is how can I achieve this without changing datacolumn datatype.

Answer 1

I don't really came up with your code but i'll give you leads to find a solution.
What is your database engine, in almost all you can define the column as Nullable, which mean you will be able to set no value. When you go to find the value you have to use somethig like the FirstOrDefault so if there is no value it is null otherway you get the value
Let's imagine you don't like the first solution, you are using a datatable, not bad but if you want to do a little more and have much more possibilities try using DataGrid, not much complicated, you just need to make something that contains the data and go for the binding magic. With this solution you can do much more and with the Object you'll be able to handle many future potential problems.
If you have any further questions ask it, i'll try the best to help you.
Hoping my answer will help you.
Have a nice day.

Answer 2

Dates are not stored with time zone or format information in the database, it is simply stored as two integers which represent an offset from a zero date.
Your code converts a column that you say is a DateTime to a string and then converts this back to a DateTime and then back to a string again.
string s = Convert.ToDateTime(row["PROCESSED__DATE"].ToString()).ToString("MM/dd/yyyy HH:mm:ss");
This is a pointless exercise, just use the date in its native format and if you want to compare use the DateTime data type.
Additionally, if you can't make the column nullable in the database, then you might want to consider using a constant to represent the empty date.
You can create a date using the date constructors without parsing it from a string.
var baseDate = new Date time(1, 1, 2000);
if (row["PROCESSED__DATE"] < baseDate) { // ... Etc
But still, you aren't going to be able to push anything but a date into the database unless you make the column nullable.
Can you not change the schema to make the column nullable?