Saving datetime to database in Xamarin Forms - xamarin

Question

I want to update the lastsync column the problem is the data wont save properly. I used Convert.ToDateTime and DateTime.Parse and still the data wont save properly. I am getting "01/01/0001 12:00:00". What am I doing wrong?
public DateTime LastUpdated { get; set; }
var current_datetime = DateTime.Now.ToString("yyyy-MM-dd hh:mm:ss");
string ofretailer_group_sql = "UPDATE tblRetailerGroup SET LastUpdated = '" + DateTime.Parse(current_datetime) + "' WHERE RetailerCode = '" + retailerCode + "'";
await conn.ExecuteAsync(ofretailer_group_sql);

Answer 1

If you are getting 01/01/0001 12:00:00 from your TimeDate field, that means it was never set/updated.
Personally I use query (?) parameters to allow the SQL statement strings to become a bunch of constants that never change and then you just have to assign the parameters for that query in the order they fall within the SQL statement:
Example:
const string ofretailer_group_sql = "UPDATE tblRetailerGroup SET LastUpdated = ? WHERE RetailerCode = ?";
await conn.ExecuteAsync(ofretailer_group_sql, new object[] { DateTime.UtcNow, retailerCode });
Note: I am using UtcNow to remove DST and phone device timezone change issues...

Answer 2

You should create dependency services for file management to save and get a data in IOS and Android level. Here is code how to save and get datetime in file.
PCL Project:- Create the interface
public interface IFileHelper
{
void SaveLastUpdatedDateTimeForData(DateTime dateTime);
DateTime GetLastUpdatedDateTimeForData();
}
IOS/Android Project:- Create one Class to save the data in file.
[assembly: Dependency(typeof(FileHelper))]
namespace ABCD.iOS
{
public class FileHelper: IFileHelper
{
public void SaveLastUpdatedDateTimeForData(DateTime dateTime)
{
try {
string docFolder = Environment.GetFolderPath(Environment.SpecialFolder.Personal);
string filePath = Path.Combine(docFolder, "..", "Library", "updatetime.txt");
File.WriteAllText(filePath, dateTime.Ticks.ToString());
} catch (Exception ex) {
Debug.WriteLine(ex.Message);
}
}
public DateTime GetLastUpdatedDateTimeForData()
{
//bool status = false;
string docFolder = Environment.GetFolderPath(Environment.SpecialFolder.Personal);
string filePath = Path.Combine(docFolder, "..", "Library", "updatetime.txt");
if (!File.Exists(filePath)) {
return new DateTime(2000, 1, 1);
}
try {
string content = File.ReadAllText(filePath);
DateTime dt = new DateTime(long.Parse(content));
return dt;
} catch (Exception ex) {
Debug.WriteLine("exception in GetLastUpdatedDateTimeForData : {0}", ex.Message);
return DateTime.MinValue;
}
}
}
}
Call the dependency Service in Client/PCL project:
Save updated DateTime:
DependencyService.Get<IFileHelper>().SaveLastUpdatedDateTimeForData(DateTime.Now);
Get Updated DateTime:
var lastUpdatedDateTime = DependencyService.Get<IFileHelper>().GetLastUpdatedDateTimeForData();

Answer 3

It seems to be a conversion issue from Date-String-Date.
I would go for directly saving first DateTime.now in Db and check if the value is saved correctly. If that works then definitely its a conversion issue. Then you can try below solution.
I do conversion like this:
DateTime date = DateTime.ParseExact(current_datetime, "yyyy-MM-dd hh:mm:ss", System.Globalization.CultureInfo.InvariantCulture);