Setting Private Variables From Datetimepicker?
Apr 3, 2010
I thought I had this figured out because it presented no errors, but when i tried to run it, I got this exception error:
Object reference not set to an instance of an object.
I am trying to set two private variables:
Private mdatStart As DateTime
Private mdatEnd As DateTime
I need to set these dates from a datetimepicker (dtpPickup, dtpReturn), but I don't now how to set it. I have tried using:
Private mdatStart As DateTime = New Date(dtpPickup.Value.Year, dtpPickup.Value.Month, dtpPickup.Value.Day)
'Private mdatEnd As DateTime = New DateTime(dtpReturn.Value.Year,
[Code]....
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Jul 23, 2010
if for example i have two private sub I declared a local variable on private sub a... is there a way that private sub b could use the variable created on private sub a? Im asking because im in a problem in my app were using global variable is not an option to make the long story short
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Mar 8, 2011
Question 1: What is the difference between "Background Worker" and "Worker Pool" as indicated within the MSDN samples provided.
Question 2: I noticed while using, AddressOf _Function_, variables cannot be passed; what would be an efficient solution to this?
Question 3: While using multithreading is it required to invoke before setting variables, or only form properties?
Question 4: While using System.Net.Sockets is it safe/efficient to use Application.DoEvents while waiting for new data; or would be using a Do While loop be fine without DoEvents since the action would be multithreaded? Note: there can be up to 2000-3000 sockets in use at a time.
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Feb 13, 2012
In our projects we use setting variables to store user setting for the applications. Moreover, with every latest version of the applications, we upgrade these variables to retain user settings.Normally, this works fine, but recently one of my end user reported an error i.e.Configuration System failed to initialize". The error is related to user.config file. Therefore we requested the user to send us his file.After received the folder, we noticed that it contains 3 files (3begfjb.newcfg,3begfjb.tmp and user. config). 3begfjb.tmp is an empty file, while 3begfjb.newcfg and user.config are identical files. We tried to open these files but the data in user.config isn't proper xml rather its unreadable formatted file.Do any you guys had experienced this sort of issue or any ideas how and what may have created these files and corrupted user.config file.
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Mar 11, 2010
I am a little new to .NET Developing, and have learned a great deal recently, but I'm stuck with something. I come from an ASP Background, I'm trying to subtract 2 variables, but they don't seem to 'see' one another.
[Code]...
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Apr 18, 2012
I am wondering if you have a class and in the class you have a function which executes a sqlcommand. Which would u use ? the local variable declaration or the private member command variable.Assuming that the class has a private field called m_Cmd as OracleCommand..i am using oracle db so i use oraclecommand , if sql server then it should be sqlCommand.[code]
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Dec 18, 2009
I'm trying to make an application that calls a function to create a timer, but I cant use WithEvents or Private inside of a function or sub, Is there any way to do this?
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Feb 28, 2010
Does anyone know how to supress the private variables from showing in the .NET Namespace? I have a Class that looks similar to this.
[Code]...
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Apr 22, 2010
I'm trying to get a handle on creating my own Interfaces for a project I'm working on. I know the MSDN help shows that all member signatures will become Public when implmented, etc, etc. However, if I implement the IDisposable interface provided by the framework, comments and private members and fields show up! Not only that, but some of the methods have comments and code within!
How did they do that? And can comments, private fields and members, and predetermined code be declared as part of an interface by the average developer?
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May 4, 2012
I am programmer from some time only, I have certain doubts in fundamentals, could you please clarify on the following:Case 1:
[Code]...
Does case 1 and case 2 yield same result, I mean is a private value necessarily in there?, can we use property itself to use its own value in its Set and get statements?
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Mar 3, 2011
comparing C# code and VB.NET and the results between the seemingly identical code were entirely different.(Why C# is always winning over VB.NET?)The explanation given is that C# will initialize the class fields, then call the base constructor, but VB.NET does the exact opposite. Is there a technical reason for the languages to be different? At first glance, it seems that either approach is equally valid, but I can't fathom why they wouldn't have selected the SAME approach.
EDIT: As 'Jeffrey L Whitledge' has pointed out, VB6 did not have inheritance, so I don't think we can say 'to keep VB.NET and VB6 more closely related'.
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Oct 18, 2011
I have a bunch of private variables I've typed out and I want to put all of my corresponding Public ReadOnly Properties in a bunch below them.Is there some way of copying ten lines of
Private _myVar As String
and pasting in ten sets of
Public Readonly Property MyVar As String
Get
Return _myVar[code]....
I'm currently copying the whole bunch of variable declarations, Find+Replacing Private _ into Public ReadOnly Property then going line-by-line expanding the definitions and writing return statements.how to avoid all this nonsense in the future, as I'm developing on a virtual terminal server, and the input lag on my little copy/paste/type operations on the code is driving me up the wall.
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Oct 4, 2010
I would like to create an interface that brings with it it's own private variables and regions.for example, if you create a class and implement IDisposable, you get all of the following:[code]
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Jul 22, 2009
give me a good resource that explains the difference between a Private, Public, Shared Functions/Sub/Variables? I normally use Public for Subs/Functions inside of Modules I call from other parts of the program. But I'd like to get more of an understanding of how and when to use them. I want as little as impact to a system that is running my programs as possible, so i guess the key here is I'm trying to just get more proficient in my coding.
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Jun 8, 2009
I came across a number of new Private Shared variables (of type Hashtables(Of String), initialized in the declaration) added to a partial class for a very large (DataContext-derived) class. This seems sensible to me in one sense because they never change, and making these shared variables ensures that they won't get re-initialized every time a function is called. However, these variables are only used within the scope of one function in the class, and I fear the private namespace of this DataContext-derived class is getting rather polluted, and having these sorts of things exposed at such a high level might be confusing to others reading the code in the future.
Would there be negative performance impact to making these local variables within the function where they are used, or is there some better way to handle this? Basically we are using these 3 hashtables to determine whether anything within particular subsets of properties changed (using GetModifiedMembers and then using the Overlaps function of the hashset to see if any of the modified members correspond to members we care about).
Edit: I caved and took the time to write my own test program, which confirmed that there is a cost to using local variables (which I assume applies generally to all cases -- I doubt there's any case where a shared variable would be slower unless using the shared variable requires some additional logic to do so properly): [Code]
So in this particular case, using the local variable costs about 200%. But in most cases (including my own), the time is probably negligible compared to the overall task. So I guess the question now becomes, how do people generally feel about improving code maintainability at the cost of negligible but known performance impacts?
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Nov 11, 2009
I have these list of RS-232 strings declared in my public class
Public Class TouchInterface
Dim WatchTVbtnCmd As String = "rs232command1"
Dim VolUpbtnCmd As String = "rs232command2"
Dim VolDownbtnCmd As String = "rs232command3"
Dim SystemOffbtnCmd As String = "rs232command4"
Dim RadiobtnCmd As String = "rs232command5"
Dim MusicbtnCmd As String = "rs232command6"
I then have this private sub. For the sake of this thread, what I would like to do is get the name of the label that was clicked which in the code below is already done, convert it to string (not sure if this needs to be done), this is also done in the code below. Next I want to compare the labelnamestring to all the variables in the public class to find out which one it is equal to and then disply that variable which should be my rs232 string in the message box. I have also added "Cmd" to the variable names above so I also need to work out how to add the text "Cmd" to the string to properly compare.
Private Sub Musicbtn_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles WatchTvbtn.Click, VolUpbtn.Click, VolDownbtn.Click, SystemOffbtn.Click, Radiobtn.Click, Musicbtn.Click, GardenVolUpbtn.Click, GardenVolDownbtn.Click, GardenRadiobtn.Click, GardenOffbtn.Click, GardenMusicbtn.Click, GardenMediaCenterbtn.Click
Dim labelname As Label = DirectCast(sender, Label)
[Code] .....
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Feb 15, 2012
i have a problem on setting the default value of my date time picker. i have created this application
[code]...
and my problem is i want to set the default value of my DateTimePicker(dtpDate) depending on which date was clicked on the calendar in Main Form. i've been posting this program of mine this past few days now. i just really need to finish this for my upcoming thesis defense.
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Mar 18, 2010
I am querying a date from my Access 2007 database in the format: MM/DD/YYYY It's then saved as a string
Depending on the month and day, it might be 1 or 2 characters. To set the DateTimePicker, it takes it as this format: DateTimePicker.Value = New DateTime(YYYY, MM, DD)
How can I switch around the characters in my string so that it can satisfy the format the DateTimePicker wants? I was thinking about some kind of reader that "consumes" characters until it reaches a delimiter ("/") and then does something with it. I remember doing that in JAVA but not in VB.NET
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Dec 4, 2011
I have a list box on my form with 2 value - "2010" & "2011". When I change the value in the listbox it should set the minimum and maximum value of 2 datetimepickers. Each time I try to change the value I get an error - for example if I change the listbox from 2011 to 2010 I get the error:
"Value of '31/03/2011 00:00:00' is not valid for 'MaxDate'. 'MaxDate' must be greater than or equal to MinDate. Parameter name: MaxDate"
If ListBox1.SelectedIndex = "0" Then
DateTimePicker1.MaxDate = #3/31/2011#
DateTimePicker1.MinDate = #4/1/2010#
DateTimePicker2.MaxDate = #3/31/2011#
DateTimePicker2.MinDate = #4/1/2010#
End If
If ListBox1.SelectedIndex = "1" Then
DateTimePicker1.MaxDate = #3/31/2012#
DateTimePicker1.MinDate = #4/1/2011#
DateTimePicker2.MaxDate = #3/31/2012#
DateTimePicker2.MinDate = #4/1/2011#
End If
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Jul 10, 2011
I didn't understand something about DateTimePicker control, on one of the site i found the Private Property Hour() as integer this property was used. And inside it was:
[Code]...
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Mar 7, 2011
I declare a variable as FRIEND in a Module. Then I instantiate that variable in a Sub in the Module. After the Sub runs, when I try to access that Variable, it is always NULL (Nothing).
Module MODULE_Main
Friend MyClass1 As Class1
Friend Sub Main()
[code]....
How do I get MyClass1 to persist, meaning how do I get access to that variable outside of the Sub that instantiates it?
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Sep 10, 2009
We have this current VBA program to help us with AutoCAD via the use of a template excel sheet.The setup we have created works well; however occasionally we have two drawings per folder, which often results in, two templates excel sheets of the same name, one overwriting the other. how I can set the active drawing name in a variable that our program uses to check for, then if not present that it creates a copy of out template and then saves it as the active drawings file name which was set as the variable
This would allow our program to locate the associated excel sheet by name then save it by the unique drawing name and prevent existing excel files being overwritten if in the same folder.
;===CODE STARTS HERE===
Option Explicit
Private Objexcel As Excel.Application
Private ObjWorkbook As Workbook
[code]....
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Dec 26, 2011
I know this is a VB.Net messageboard, but it can work with in all languages. Is there a quick way to complete a line (sample code):
//Setting variables set 1
a = e;
b = f;
c = g;
d = h;
.....
//Saving changes set 2
e = a;
f = b;
g = c;
h = d;
without having to type everything out...A technique using EXCEL or Notepad....Find and Replace. This would save a lot of time coding and becomes pain in the butt when you working with many variables.
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Oct 6, 2010
.From = New MailAddress("Me@MySite.com", "Big Mike")This does not;
Dim AddressFrom As String = "Me@MySite.com"
Dim FromDisplayName As String = "Big Mike"
.From = New MailAddress(AddressFrom , FromDisplayName)
I receive the error; The specified string is not in the form required for an e-mail address.I would REALLY like to use variables here so that I can read these two pieces of data from My.Settings. I've been searching for the answer for hours and I'm stumped.
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Apr 14, 2011
I am working with binary files that have 500 rows and 500 columns (width x height). When I load these files into array I set width and height variables to 500 and I was wondering instead of hard-coding like that how I can code in a way that the program should find the # of rows and # of columns of the file before loading the file into array...
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Dec 1, 2011
I'm developing a revised version of a system I have been using for years, but with all the advantages of .NET features that were not around when I first made this. It's proving a steep learning curve! So, when a user logs in through my Login.aspx page which simply compares username/password to Database record, the system creates a session variable containing the user's Username and various other things. There are two type of variable which will be common to all elements of this system
User Specific data, Username, Permissions, etc
Setting variables, drawn from a database of pre-set facilities which are setup within the system, some will determine which facilities work, how they work, and some will be dependent upon the User's permission. Obviously, I could set everything within the Session data, but that'd be inefficient wouldn't it? If I were to set these globally available variables in my App_Code, how would I go about setting this up so that, for example, those variables which require a database call, are set for the duration of the Logged-In session and do not require constant Database lookups? Further to that, those variables which are dependent on the session state, would need clearing on each LogOut. I am using VB.NET.
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Jul 29, 2009
I have an xml document on the internet right. Lets say it contains:
<tag>goose</tag>
What I want to do, is when the user clicks a button in my vb form it looks for the "tag" tag and finds the text inside the tags which is goose. Then it sets a label to equal goose, or whats in those tags.
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Nov 18, 2011
I'm setting up a simple app that has 2 variables, one from a combobox and one from a textbox.Putting all my code directly in the button1_click sub works just fine, however, I wanted to add a marquee progress bar so I tried to implement a backgroundworker.
[code]...
and call it with Me.Invoke(New SetComboBoxTextDelegate(AddressOf SetComboBoxText), ComboBox1.Text)but it still throws the Cross-thread operation invalid error.
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Dec 14, 2011
I am completely lost on procedures. Whats the difference bewteen Private sub and private function?
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Dec 11, 2011
Last year (2010) I came across a FANTASTIC command that allowed me to take a string of variables with a common delimiter and break it all back out into separate variables (possibly an array) with one statement.
[Code]...
As long as the delimiter was a unique specifiable character, this one-statement command could break it out into elements. my memory and point me in the right direction.
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