C# Discussion Boards - CodeProject

Re: Converting strings to datetime

Luc Pattyn16-Oct-11 8:48

Luc Pattyn

16-Oct-11 8:48

As it represents a date/time, it should be a DateTime type. Please don't advise people to perform string operations on objects that represent numbers, DateTime.Parse/TryParse/ParseExact/TryParseExact are easy enough to do it right.

Luc Pattyn [My Articles] Nil Volentibus Arduum
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Re: Converting strings to datetime

André Kraak16-Oct-11 2:35

André Kraak

16-Oct-11 2:35

You can also use the ParseExact[^] method for which you can specify the date format of the string to be parsed.

CultureInfo provider = CultureInfo.InvariantCulture;

DateTime.ParseExact(oDate, "yyyyMMdd", provider);

0100000101101110011001000111001011101001

Re: Converting strings to datetime

OriginalGriff16-Oct-11 2:37

OriginalGriff

16-Oct-11 2:37

Snap!
There is also TryParseExact as well.

Ideological Purity is no substitute for being able to stick your thumb down a pipe to stop the water

Re: Converting strings to datetime

Richard MacCutchan16-Oct-11 2:41

Richard MacCutchan

16-Oct-11 2:41

Something else I've learned today. Smile | :)

Unrequited desire is character building. OriginalGriff

Re: Converting strings to datetime

OriginalGriff16-Oct-11 2:56

OriginalGriff

16-Oct-11 2:56

I hope the other was rather more interesting! Laugh | :laugh:

Ideological Purity is no substitute for being able to stick your thumb down a pipe to stop the water

Re: Converting strings to datetime

Richard MacCutchan16-Oct-11 3:03

Richard MacCutchan

16-Oct-11 3:03

It would struggle to be less so! Laugh | :laugh:

Unrequited desire is character building. OriginalGriff

Re: Converting strings to datetime

CCodeNewbie16-Oct-11 2:41

CCodeNewbie

16-Oct-11 2:41

Hi André

Tried that too... "01/01/0001".

I think the problem is that the parser doesn't recognise 20110325 as a date

If I do this

DateTimeFormatInfo myDTFI = new DateTimeFormatInfo();
myDTFI.DateSeparator = string.Empty;
myDTFI.FullDateTimePattern = "yyyymmdd";
string oDate = subKey.GetValue("InstallDate", String.Empty).ToString();
DateTime nDate = DateTime.ParseExact(oDate,"yyyymmdd", null);// same result if I use "CultureInfo.whatever"
Console.WriteLine(oDate);
Console.WriteLine(nDate);

I get this

20110325
25/01/2011 00:03:00
System.FormatException: String was not recognized as a valid DateTime.

Re: Converting strings to datetime

André Kraak16-Oct-11 2:46

André Kraak

16-Oct-11 2:46

Use 'MM' instead of 'mm'.
'MM' is for months and 'mm' is for minutes.

0100000101101110011001000111001011101001

Re: Converting strings to datetime

OriginalGriff16-Oct-11 2:36

OriginalGriff

16-Oct-11 2:36

Try:

string strDate = "20110325";
DateTime date = DateTime.ParseExact(strDate, "yyyyMMdd", CultureInfo.InvariantCulture);

string strDate = "20110325";
DateTime date = new DateTime();
if (DateTime.TryParseExact(strDate, "yyyyMMdd", CultureInfo.InvariantCulture, DateTimeStyles.None, out date))
    {
    ...
    }

Ideological Purity is no substitute for being able to stick your thumb down a pipe to stop the water

Re: Converting strings to datetime - 1000 pts to Griff

CCodeNewbie16-Oct-11 2:56

CCodeNewbie

16-Oct-11 2:56

RegistryKey Regkey = Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall");
                {
                    if (Regkey != null)
                    {
                       foreach (string subKeyName in Regkey.GetSubKeyNames())
                        {
                            RegistryKey subKey = Regkey.OpenSubKey(subKeyName);
                           
                            string oDate = subKey.GetValue("InstallDate", String.Empty).ToString();
                            if (!String.IsNullOrEmpty(oDate))
                            {
                                DateTime date = new DateTime();
                                if (DateTime.TryParseExact(oDate, "yyyyMMdd", CultureInfo.InvariantCulture, DateTimeStyles.None, out date))
                                   Console.WriteLine(date);
                            }
                           
                            subKey.Close();
                        }

produces 25/03/2011 00:00:00

Thanks to everyone for their time

Re: Converting strings to datetime

jschell16-Oct-11 9:33

jschell

16-Oct-11 9:33

CCodeNewbie wrote:
How do you convert the string 20110325 to a datetime with a "yyyy-mm-dd" format?

Very carefully.

There reason for that of course is because you do not have a "date time".
You have a date.

And there is a difference because a date time has a timezone. Where a date probably doesn't. Or maybe it does. But that is where the 'care' part comes in.

Re: Converting strings to datetime

BobJanova16-Oct-11 22:40

BobJanova

16-Oct-11 22:40

Good points. C# (or, I should say, the .Net Framework) doesn't have a Date class, though, so he does mean DateTime. It looks like the date is in the same time zone as the application so he shouldn't have an issue with that.

DataRow usage

SFORavi15-Oct-11 10:51

SFORavi

15-Oct-11 10:51

Hi
For my assignment, want to test out DataRow to insert a new row in to a test table with just one column.

Based on code below I am getting the Data grid populated in the Form, with values in table. But Insert errors out in statement

DataRow dRow = ds.Tables["testtbl"].NewRow();

saying a object reference is missing for dRow. Not sure what the issue is. I thought the NewRow is good enough.

Can you please help to overcome this issue.

namespace SalesAudit
{
    public partial class Form1 : Form
    {

        string strConnection = "Data Source=.;Initial Catalog=Company;Integrated Security=True";


        public Form1()
        {
            InitializeComponent();
        }

        

        private void button1_Click(object sender, EventArgs e)
        {

            SqlConnection sqlconn = new SqlConnection(strConnection);
            DataSet ds = new DataSet();
            string sqls = "select * from testtbl";

            SqlDataAdapter da = new SqlDataAdapter(sqls, sqlconn);

            sqlconn.Open();
            da.Fill(ds);
            dataGridView1.DataSource = ds.Tables[0];


            SqlCommandBuilder cb = new SqlCommandBuilder(da);


            DataRow dRow = ds.Tables["testtbl"].NewRow();

            dRow[1] = "test";

            ds.Tables["testtbl"].Rows.Add(dRow);
                              

            da.Update(ds, "testtbl");


            sqlconn.Close();

        }
    }
}

Re: DataRow usage

SFORavi15-Oct-11 11:08

SFORavi

15-Oct-11 11:08

Got it to work

Had to add the table name testtbl in line below..

da.Fill(ds,"testtbl");

Thanks, Ravi

Re: DataRow usage

Luc Pattyn15-Oct-11 11:15

Luc Pattyn

15-Oct-11 11:15

or just do

DataRow dRow = ds.Tables[0].NewRow();

i.e. refer to the table as you did a few lines earlier.

Smile | :)

Luc Pattyn [My Articles] Nil Volentibus Arduum
iSad

Re: DataRow usage

SFORavi15-Oct-11 13:34

SFORavi

15-Oct-11 13:34

Thanks, your suggestion is the right way to refer to the table instead of giving it a name as I did.

Thanks much it works great now.

Re: DataRow usage

BobJanova16-Oct-11 22:43

BobJanova

16-Oct-11 22:43

Actually, I'm not sure about that. Giving the table a name means that the lookup will always be the same, even if you change the access to load some other query into ds first. I'd do

da.Fill(ds,"testtbl");
DataTable testtbl = da.Tables["testtbl"];
DataRow dr = testtbl.NewRow();
// ... etc using 'testtbl' as the table

How to inset picture in text box?

Mmohmmad15-Oct-11 7:24

Mmohmmad

15-Oct-11 7:24

I wonder if anyone could help me on adding picture in text box
Sincerely Yours
Smile | :)

Re: How to inset picture in text box?

André Kraak15-Oct-11 7:56

André Kraak

15-Oct-11 7:56

This question was already posted in Q&A[^]; please post in one location only.

0100000101101110011001000111001011101001

Re: How to inset picture in text box?

RaviRanjanKr16-Oct-11 10:39

RaviRanjanKr

16-Oct-11 10:39

You should be stick at one place don't try to Cross post. you can use "Have a question or Comment at bottom of answer" to revert back answerer.

Re: How to inset picture in text box?

JP_Rocks20-Oct-11 3:26

JP_Rocks

20-Oct-11 3:26

please do not repost

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Live Data in an application

vjs244515-Oct-11 3:04

vjs2445

15-Oct-11 3:04

Hi,

I am looking for some recommendations about an application model I need to generate.

This application will be used by multi-users in multiple locations.

I have Database and I need to display around 20 to 30K records in front end application and also wants to show Live Data as well modified data from database.

What are different technologies I can utilize in DotNet FrameWork?

This is what I came across from my thoughts:

Backend Data Source: Database
For logic and data extraction : WCF
Front End App: Multi-Threaded app (not sure about web based or desktop based.)

Can somebody with experience can guide me?

Regards,

Re: Live Data in an application

Eddy Vluggen15-Oct-11 3:22

Eddy Vluggen

15-Oct-11 3:22

vjs2445 wrote:
This application will be used by multi-users in multiple locations

vjs2445 wrote:
Can somebody with experience can guide me?

People usually work on a snapshot of the data, and databases usually don't notify the app that there has been a change in the dataset. Sql Server has the Notification Services, might help.

You could keep everything in memory, using the INotifyPropertyChanged interface, and broadcast all changes to each client. Sh*t happens when two people simultaneous edit my name.

How much users, in how many locations? I don't like the idea of updating a 5Mb blob and sending the new version over the network to a 1000+ users, it might cripple the network very fast, whilst most users aren't even working/viewing that particular blob.

Bastard Programmer from Hell Suspicious | :suss:

Re: Live Data in an application

vjs244515-Oct-11 3:32

vjs2445

15-Oct-11 3:32

Well before this I need to know what are the different concepts and Technologies and different level I can use to fit in this kind of app model.

Re: Live Data in an application

Eddy Vluggen15-Oct-11 4:39

Eddy Vluggen

15-Oct-11 4:39

This is not a standard application model, due to aforementioned problems, and doesn't happen out-of-the-box.

It'd be wiser to create a webapplication and have it poll using Ajax to show the user the latest snapshot of the data he or she is using right now, as opposed to sending every change to every user, regardless whether they need it or not.

Bastard Programmer from Hell Suspicious | :suss:

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