In vb.net, is there a way to set a datetime variable to "not set". And why is it allowed to set a date to Nothing and NOT allowed to check if it is Nothing, like this:
Dim d As DateTime = Nothing
Dim boolNotSet As Boolean = d Is Nothing
This throws an error with this description:
'Is' operator does not accept operands of type 'Date'. Operands must be reference or nullable types.
i need to check for a specific DateTime value in my table from my code (VB.NET) and i don't know how to format the DateTime as a string. i've read that SQL Server will recognize my string if it's in either date, time, or date and time format. i mean:
'May 15, 2004'
'5/15/2004'
'20040515'
[code]......
<VB.NET 2005+SQL server 2005>
Error has to be raised for input text by user. User will input data on datagridview. Below are examples of use input.
1. "2009/01/23 08:00:10" --> How do I know that right datatime format or not
2. "2009/15/23 08:00:10" --> How do I check the month is wrong
So I'm kind of new to VB and am just playing around with a little project, I currently need a loop that is constantly checking the systems clock to see if it's equal to a certain time.
While Not myTime.Hour = 24
If TimeOfDay = newTime Then
nfi.ShowBalloonTip(15)
[code].....
how to check the server DateTime when the application launch. i want to make sure the user PC has the same DateTime as server when the user use the application. Reason being is some user may tend to change their DateTime backward and it causes a major confusion when it update in the server database. Below is my code....Both of the code giving problem and does not compare the date time to my pc datetime... how to check the the server datetime is same with the pc server time....
Public Sub GetServerDateTime()
Dim WMIScope As Management.ManagementScope
Dim WMIConnectionOptions As New Management.ConnectionOptions
[Code].....
I have two textboxes on the screen. They are used for startdate and enddate. If the user does not enter anything in the textboxes I pass nothing (VB.NET) to the webservice. When the webservice receive it on the other end it shows the value "#12:00:00 AM" which I think is the default for the datetime field. Anyway, now I do not want to pass this value to Stored procedure since it will not work. How can I check before sending values to sproc that the value is not the default datetime.
View 3 Replieshow to convert string to datetime and calculate date
View 3 RepliesI'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.
View 1 RepliesI'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.
datetime1 and datetime2now two fields are have data ( date )in table recordi want to update only datetime2 is an emptyi am using visual basic 2010 ( visual studio 2010
View 1 RepliesI try to compare Datetime.Now with a Datetime variable I set, using the Datetime.CompareTo() method. I use a timer to compare these every second and display the result, but as the current time approaches the time I set, the result changes from 1 to -1, but never 0, which means these two are never equal. I'm suspecting the Datetime structure contains milliseconds?
View 7 RepliesAssume the following program is started at 1:59:01 AM on 3/13/2011 in the United States. The first time Timer1 ticks what will be the value of the TimeSpan (ts)?
Public Class Form1
Private Sub Timer1_Tick(sender As System.Object, _
e As System.EventArgs) Handles Timer1.Tick
[code].....
I'm trying to add the date and time of Today into a Sql-database-field that has the datetype datetime.
[Code]...
the msgbox gives me the following result: 29/01/2011 18:49:21 my sqlException gives me the following error: 102 - Incorrect syntax near '18'. Is it better that i set the datatype to char in my sql database? It's maybe a bit easier? When I do that, can I calculate with these date?
How do I convert ISO datetime to locat EST with vb.net?
I have input time as e.g. "20091027T1639Z" which is ISO GMT.
[code] "The conversion of a char data type to a datetime data type resulted in an out-of-range datetime value.The statement has been terminated." [code]
View 6 RepliesThis is my problem.I have a field set up in MS Access to Boolean YES/NO, this field is populated when the user check a checkbox on a windows form. If the user check a checkbox, the value is written as checked in the data field (MS Access).The problem is when I search for the user information, I need the information from the Data base to populate(return) to the windows form. Example: If I enter a users phone number and the user data is present, the form gets populated with the information the user previously entered which was store in the database.Example: If the user selected checkbox1 and submits the form. When I search for the user info, the check box should check(populate) because the user had checked it on submit.Here is what I have done:
[code]...
I am getting the check value correctly in the database using a Boolean.Here is one of the errors I am getting. Unable to cast object of type
'System.Boolean' to type 'System.Windows.Forms.CheckBox.I am having trouble putting the codes in a code tag or block
My application is like this : i have to search my data from database with some check box and text box when user select check box specific function go on and then when user enters some range of value in textbox then the result will shown in data grid view after that i can print it by selecting data
my vb.net code is as follow:
Imports System.Data
Imports System.Data.SqlClient
Public Class XtraForm1
[CODE]............
I m also pasting the demo picture.
Details: I want to compare these above two table1 and 2 . The unmatched records should be save in a new table .
objectives
1 Should take input the table and fields we want to match each other.
2 Then after searching or reading the record from table and selected fields save the unmatch records in a new table
hi there,first of i know nothing at all and my goal is to make a app for xp to check a database and check/patch a iso and then to burn the result to dvd-dl, basically like a app called abgx360 checks the database then like xbox backup creator burns the game, i'd like to make a app to do both, i'm going to college next year in september to learn programing c+ andf a few other things, but thats a longtime away.
View 14 RepliesIs there a way to check specific pixels in a picturebox to check the color? Basically what I have is a black square with some white dots, and I want to find the position's in the picture of the white dots.
View 2 RepliesI have a Boolean that writes to a data field. The data field(column) is set to YES/NO, if the user check a checkbox, the value is written as check in the data field.The problem is when I search for the user information, I need to get to form to the state it was in when the user submitted it.
Example: If the use select checkbox1 and submits the form. When I search the form, I need to make that particular check box check.
[Code]...
I use check boxes and place them on my user interface (See attachment)I have coded the code for "select all" button :
Code:
Private Sub checkedall_Click(ByVal sender As System.Object, ByVal e As_
System.EventArgs) Handles checkedall.Click
Dim chkboxes, outs As New Collection()
[code]....
I could not seems to check all the boxes. Is there something wrong with it? I am not sure how to assign array to check boxes.
A couple of questions about check list boxes:
How to check/decheck all the item in the list How do you copy or delete all checked items in the list
How to check a check box based on a condition at run time?
View 3 RepliesHow can i allow the user to only check one check box on a CheckedListBox1..I was thinking of using a timer but that might be a stupid thing to do.
View 3 RepliesI'm using VB .NET & SQL Express 2005.I was hoping someone could help me figure this out, I'm trying to search a table between two dates. The table has a datetime column and I am using VS .NET 2005 DateTimePicker control. I'm not getting any errors, but I'm not getting any results either..
[Code]...
In my vb.net winform application, I am moving the file from one folder to another. I need to store the datetimevalue when the transfer has been done. Later I need to show this DateTime value in my Grid. Here is the code i have written, but not able to store the datetime value.
[Code]...
the last date was saved on database is: 6/13/2012 12:27:30 PM
In my DateTime Now is:6/13/2012 01:27:57 AM
but, when I execute this function, it always say:"Date has been manually modified, Please Set to Valid DateTime" But, DateTime Now is NOT lessthan the Date from my Database. What's wrong?
This is the code, please correct it,
[Code]...
I have a DateTime object I want to compare against an sql datetime field in a where clause. I'm currently using:
"where (convert( dateTime, '" & datetimeVariable.ToString & "',103) <= DatetimeField)"
But I believe datetimeVariable.ToString will return a different value depending on the culture where the system is running.
How would you handle this so it is culture independent?
EDIT : I won't be using paramatised sql in this code...
EDIT : following Parmesan's comment to one of the answers looks like the best method may be:
"where (convert( dateTime, '" & datetimeVariable.ToString( "s" ) & "',126) <= DatetimeField)"
[Code]in my program, i've created a function wherein i will get the min timeentry for type 0 and it depends on the current date. so heres how it goes [Code] what should i put as the value of time entry? i tried format(var,"m") but no success. in the code i post above it also does not work. i get this error "The conversion of a varchar data type to a datetime data type resulted in an out-of-range value." how can i match the value in the database and the current date so that i can retrieve a value?
View 2 Replies