Big Endian Values Into And Outfrom System.DateTime
Jul 26, 2011
I'm working on a project that's going to be deployed via .NET on Windows and via Mono on Linux; the same data needs to be exchangeable between the platforms, including where platform A is Little-Endian and platform B is Big-Endian.Where text is concerned, I know ASCII/Unicode is natively Big-Endian, so there's no problem with that.Where numbers are concerned, I know that byte arrays have to be reversed on Big-Endian platforms to store the data in Little-Endian format.But what exactly is the 64 bit value output from System. Date Time.ToBinary?Is this a number representing the number of seconds elapsed since Jan 1 1970, is this some kind of serialized attribute that outputs some DotNET-recognizable value, or what?Does this byte array need to be handled differently in Big and Little Endian environments?It never hurts to try. In a worst case scenario, you'll learn from it.
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Apr 14, 2010
I need to be able to read bytes in Little Endian and in Big Endian as well. Is this possible to do in VB? I know that VB reads in Little Endian by default, but I also need to read in Big Endian.
I have tried this:
Dim i1 as Long
Dim fs As New IO.FileStream(filename, IO.FileMode.Open)
Dim br As New IO.BinaryReader(fs, System.Text.Encoding.BigEndianUnicode)
[code]....
This return the value "1616183296" when it is supposed to return "21856". I've opened the file up in Hex Workshop, and looking at it in Little Endian, I do get the value of "1616183296" and in Big Endian, I get the value of "21856".
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Oct 20, 2011
I am trying to communicate with a Omega Instrument using serial port communication. Omega Instrument has Motorola Format and i am using VB.NET as programming language. I have to perform byte swapping and send command 54h to the Omega Instrument so that it will display RMT.
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May 7, 2010
I'm trying to match a certain DateTime value with the current system DateTime. I have a timer and a label on a form. Timer interval is set to 1000. When the form loads, the timer starts ticking. As soon as the current DateTime matches the value of the variable, it shows a message in the label. When I'm writing the following code, the values don't match even if the current system DateTime is equal to the variable. Label1 isn't showing 'Times Matched':[code]The default format of 'Now' is the same as I have stored in dtmVar variable. So there's no question of format mismatch. Does that mean 'Now' is not actually a DateTime property? Provided, my O.S. is Windows Vista Ultimate and all date/time settings are set to default.
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May 1, 2010
I'm trying to match a certain DateTime value with the current system DateTime. I have a timer and a label on a form. Timer interval is set to 1000. When the form loads, the timer starts ticking. As soon as the current DateTime matches the value of the variable, it shows a message in the label.
When I'm writing the following code, the values don't match even if the current system DateTime is equal to the variable. Label1 isn't showing 'Times Matched':
Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
Dim dtmNow As DateTime
[Code]....
Why is it so? The default format of 'Now' is the same as I have stored in dtmVar variable. So there's no question of format mismatch. Does that mean 'Now' is not actually a DateTime property? Provided, my O.S. is Windows Vista Ultimate and all date/time settings are set to default.
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Oct 2, 2009
Im working on my first n-tier application. I am trying to serialize a structure and Im getting an error"Soap Serializer does not support serializing Generic Types : System.Nullable`1[System.DateTime]."Here is the structure that is being serialized
Namespace Structures
<Serializable()> _
Public Structure structAllergy
Public AllergyID As String
Public ProfileID As String
[code]....
The bold line is the line that is throwing the error.
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Aug 16, 2010
I am fetching DataTime value of a SQL Database, LockDate. Dim diffDate As TimeSpan diffDate = DateTime.Now - LockDate minutes = Convert.ToInt32(diffDate.Minutes) hours = Convert.ToInt32(diffDate.Hours) Minutes value is showing incorrect values.
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Oct 8, 2010
Is there any difference between using the Microsoft.VisualBasic.DateAndTime.Now compared to the System.DateTime.Now? I seem to remember reading something that said the MS.VB namespace was for legacy use only, and was much slower than using the native .net classes.
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Oct 26, 2009
I'm converting a stream of bytes from a network packet into a specific struct, and vice versa. For example, when converting a short back and forth, my method looks like this:
myShort = buf(0) + (buf(1) * 256)
or the other direction:
buf(0) = myShort mod 256
buf(1) = myShort 256
When it comes to a 4 byte integer, after some experimentation I found that converting from the byte array to integer is done this way:
myInt = buf(0) + (buf(1) * 256) + buf(2) + (buf(3) * 256)
Basically adding two shorts together. I'm not quite sure to do the reverse of that, to fill the 4 bytes from myInt.
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May 24, 2012
I'm tried creating an analog clock and I realized I was terrible at trig and gave up. So instead I'm just creating a digital clock. I'm having problems getting the alarm to go off. Lemme explain my layout, I have 3 comboboxes. 1 is for the hour, 1 is for the minute and 1 is for am/pm.
Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
'The commented out variables are global
[Code]....
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Jun 29, 2011
To populate my database I have been using the builtin SQLite command for datetime:INSERT INTO samples (timestamp, sample_value) Values(datetime('now','localtime'), ...)When I look at this on my Mac using a SQLite Reader called Base I see the following timestring:
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Feb 1, 2011
suppose i have meeting 31/1/2011 9.30 and when current time becomes 31/1/2011 9.30 it displays a
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Dec 14, 2011
So i have one file, that has one header that tells me if the bytes are in little or big endian format.The content of the file after the file is something like this, one byte that indicates a new "section", then several bytes until the other "section". This bytes each one represent the number of the bytes that i need to read in the second section.
[Code]...
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Mar 28, 2011
I have a problem when i am passing negative value to "AddMinutes" function.The problem occurring when i subtract a value from the "00:xx:xx".[code]When it is trying to subtract, it is throwing the "Un-representable DateTime" error.How do I do the subtraction of minutes in this scanerio?
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Apr 20, 2010
I currently receive spreadsheets from clients which include several date fields. Since these are coming from many different sources, the date formats can vary widely (although they will all be US format). It could be "April 19, 2010", "4/19/2010", "2010-04-19", etc. I would very much like to use the DateTime.Parse function rather than having to write my own parsing function--I don't want to have to write out every possible combination of date strings.
The problem is, the DateTime.Parse function includes default values if all values are not supplied. So if the field comes in as "03/2009", since no day was specified, the function will return a datetime equivalent to "3/19/2009" (today's day along with the values given). I cannot use this. If a client provides a date that is incomplete, my program must produce an error, not fill in default values for them. Is there a way to tell DateTime.Parse not to use default values? Or perhaps there's another function that can parse multiple string formats into DateTime type without using defaults?
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Feb 24, 2009
I am using VB.net 2003 application program. I am trying to do a select statement whereby I'm searching between 2 datetime values that are being stored as datetime. records are stored inside Access. For example, I am searching between 2 datetime:
StartTime = 2/23/2009 9:00:00 AM
EndTime = 2/23/2009 11:30:00 AM
So I need to find all the records in between 9:00 AM and 11:30 AM on 2/23/2009.
strSQL = "select OrderID from Orders Where OrderDate >= ('" & StartTime & "') AND OrderDate <= ('" & EndTime & "') "
but i got the error showing below:
An unhandled exception of type 'System.Data.OleDb.OleDBException' occurred in system.data.dll
strSQL = "select OrderID from Orders Where OrderDate >= DATEVALUE('" & StartTime & "') AND OrderDate <= DATEVALUE('" & EndTime & "') "
But when I use DATEVALUE, it takes the date from the string and set time as midnight (00:00:00). So it returns no records between 9:00 AM and 11:30 AM on 2/23/2009, but I can see there are records. [Code]
strSQL = "select OrderID from Orders Where OrderDate >= TimeValue('" & StartTime & "') AND OrderDate <= TimeValue('" & EndTime & "') "
And when I use TimeValue, it returns the time from the string and set date as jan 1st. so it returns no records between 9:00 AM and 11:30 AM on 2/23/2009, but I can see there are records. [Code]
but none of the codes above is returning records between 9:00 AM and 11:30 AM on 2/23/2009, but I can see there are records. i searched and found all those examples. but that didn't work. Is there anyway i can search between 2 datetime values. i need to find all the records that lies between that time period (for example: between 9:00 AM and 11:30 AM on 2/23/2009).
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Jan 24, 2011
Weird problem that just started, I am using an OleDbCommnad to create a dataadapter then fill a table everything from a .csv file, works fine except no dates are coming over? I added a datagrid view to my project just to see and any column that should have a date value is empty. I confirmed that the column is of System.DateTime value so I am at a complete loss?
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Sep 29, 2009
my form need to show the current date when click on button. the code inside the button is TextBox1.text = System.DateTime.Now.After clicking, the textbox show "9/29/2009 4:32:10 PM" may i know is it possible for me to show only the date and also to change the format to dd/mm/yyyy?
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May 23, 2011
I would like to be able to display null values in a datetime picker control. I am using one datetime picker control for both datadisplay and data entry. when I load the data from the database and if there is no date then the datetime picker control must be blank.
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Aug 22, 2010
I have been dabbling in VB before and i played around wiht linq to sql back then but im wondering what i should go with here.I need to have a list of people.. They should all have their own id nr.
The people in the list are supposed to keep a record of values changing over time with a datetime stamp. (In my case its numbers from a test outcome of blood)You have to be able to add people and delete people. All records will be deleted too.A Chart will read information from the records and display changes over time in chart.I was thinking of doing it with linq to sql and i was kinda aiming at Creating datatables with id names from the script
Havent found a way of creating datatables from a script though..I was hoping for a solution like that.. And i was hoping id be able to search databasetable names.
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Nov 13, 2011
I tried the following, but i get the error
constant expression is required
Public Sub ExampleSub(ByVal Test as string,
Optional ByVal fromDate As System.Nullable(Of DateTime) = Date.Today)
'A Great sub!
[Code].....
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Jun 21, 2010
I am looping through a list of DateTime variables and have got the .ToUniversalTime variable. I want to find out from the list which is the closest one approaching Now.ToUniversalTime but am having difficulty trying to work it out I had it looping through like this but this isn't much good as I only want to return the one that is the closest approaching to the system time. If TodaysCard(i).eventDate.ToUniversalTime < Now.ToUniversalTime
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May 28, 2010
I'm trying to create a Windows form application which uses a few data grid views to pull data back from a SQL Server database. I've managed to get the data back okay from the tables but what I want to do is filter that data dynamically based on values input by the user from a combo box and a date time picker. Each of the data grids display production data for a machine but the combo box and date time picker will allow the data to be filtered by shift and date respectively - how to I pass the values of these to the SQL query returning the data?
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Nov 30, 2011
I am trying the following to select a long date, but becase the value is stored in SQL database as DateTime I am unable to return any results unless minutes and seconds match perfectly...I then tried to use 2 calendars and have the same issue with the DateTime format..
CODE:
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Jan 13, 2011
I have a DataTable with two DateTime columns: "start_time" and "end_time".Now, I want to add a third column that calculates the difference between the two DateTimes. But I can't seem to figure out how. I've tried to set the .Expression-value to "start_time - end_time", but it says that "-"-operator is not allowed on DateTime.
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Dec 26, 2011
I need to display on my datagridview the data from MYSQL db, but I'm having a problem on a field which is in DATE format in mysql
cmd.CommandText = "SELECT * FROM tbl_user_log"
cmd.Connection = sqlcon
dr = cmd.ExecuteReader
[code].....
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Mar 15, 2010
I have a text string like this which I will need to parse: FriMar1200:00:00EST2010 And I used the following Date.ParseExact("FriMar1200:00:00EST2010", "dddMMMddHH:mm:sszzzyyyy", Nothing) And it is giving me a A first chance exception of type 'System.FormatException' occurred in mscorlib.dll error.
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Aug 24, 2011
I used .NET Framework 1.1 in C/S project before. Now I have updated the project to use .NET Framework 3.5 without modifying source code, but I have found that : the Remoted DateTime values can not be converted to the equivalent local time of a remote computer that is in a different time zone. In .NET Framework 1.1, the DateTime values can be converted automatically.
[Code]...
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Jan 31, 2009
I have got a MySQL database that has got some dates stored in a Date format (YYYY-MM-DD) however when i try and import the data i get an error saying: "Unable to convert MySQL date/time value to System.DateTime"
[Code]...
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Mar 23, 2011
how to convert string to datetime and calculate date
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