I have thought of a new project to keep me busy for a while, and it involves a more advanced GUI, specifically I want to display a map and put objects on it or highlight certain areas for example. I've been searching the forum for a little while and ran into two options for more advanced GUI building: WPF and GDI.
View 2 Repliesjust want to know what is the difference between these date values?Once some one told me that its difference is server date and client date but not sure which one he meant.Below is 3 type of date currently I'm using and don't know what is the difference between them.
DateTime.Now is from System.DateTime.Now
Now is from Microsoft.VisualBasic.DateAndTime
Today.date is also from System.DateTime
I have a book from a friend called "Teach Yourself Visual Basic in 21 Days" and so far what I have read has been very nice and easy to look at as well as understand. It also seems like it will do what it says it will do. One problem is it was published in 2006 so it uses VB Studios 2005. There is a rather large difference between 2005 and the new 2008 Express edition and I see the new 2010 beta so I wondered: "light from above, is it worth looking for the 2005 edition of Visual Basic Studios Express Edition or should I rather just look for another book and start working with this 2008 edition? I really fancy this book on the 2005 edition but seeing as it doesn't even have the XP window styles in the figures it might be a little outdated and this new 2010 edition might blow away 2008! I am so confused. Should I throw out the old and go with the new, or should I work with 2008 until IT'S time is up? Is it worth it in this new economy and fast paced evolving career opportunity?" Well, I didn't get a response form the great Computer Techie in The Sky, so I am asking you... What should I do? I understand that it might be better to learn with this new 2008 edition but even still I would imagine their are some 2005 based programs out there people use that might need updating. As a beginning programmer I don't know where to go.
View 3 RepliesI had a .chm file I used in VB2008 and I'm having trouble getting it to work for VB2010. I use the code below to reference the file.
vb
Module HTMPHelpAPI Public Const HH_DISPLAY_TOPIC As Short = &H0 Public Const HH_DISPLAY_TOC As Short = &H1 Public Const HH_DISPLAY_INDEX As Short = &H2 Public Const HH_DISPLAY_SEARCH As Short = &H3 Public Const HH_HELP_CONTEXT As Short = &HF Declare Function HTMLHelp Lib "hhctrl.ocx" Alias "HtmlHelpA" (ByVal hwnd As IntPtr, ByVal lpHelpFile As String, ByVal uCommand As Int32, ByVal dwData As Int32) As Int32End Module
I then call it from my menu using this:
vb
Private Sub HelpToolStripMenuItem1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles HelpToolStripMenuItem1.Click HTMLHelp(IntPtr.Zero, "PE Files Help.chm", HH_DISPLAY_TOC, 0) 'Dim sHelpFile As String 'Dim sStartupPath As String 'sStartupPath = Application.StartupPath.ToString 'sHelpFile = Replace(sStartupPath, "in", "hlp") & "PE Files Help.chm" 'Me.hlpHtmlLocal.HelpNamespace = sHelpFile End Sub
I had found the commented out portion online and tried to get it to work, but nothing will bring up the file. Do I need to have it loaded into VB.Net somehow or point to it or does it need to be in a certain location?
I am having trouble. My string dictionary saves a controls.tag value then saves another value to that key(controls.tag)for example I store to my string dictionary like this:
vb.net
StringDictionary.Add(txtSAP_Phasing.Tag, "YES")
How can I match the values even if they are not the same case.my problem is im trying to match each controls.tag with the proper key in the dictionary.But the dictionary saves the string of the txtSAP_Phasing.Tag value as all lowercased, and the Tag value is actually all uppercase... and this is causing my IF THEN statement to not trigger when I try compare the two strings.
I have the following
If Trim(txtConfirmationDate.Text) <> "" Then
sqlinsert2.Parameters.AddWithValue("@CONFIRMDATE", CDate(txtConfirmationDate.Text))
Else
sqlinsert2.Parameters.AddWithValue("@CONFIRMDATE", VB.vbNull)
End If
Unfortunately, it writes "01/01/1900" to the database. How do I get it to just leave the field as NULL?
I did a project (College Management) in vb.net 2008 which contains 13 forms in it. I designed the different functions in a different normal form, i.e. frmAdmission, frmSearch etc. When the project run's the main form is loaded. When user chooses a particular function say 'frmSearch' then the main form is unloaded and the form frmSearch is loaded. Now my lecturer told me to use MDI forms instead of normal forms because, normal forms takes larger memory than the MDI forms.
View 5 RepliesIn VB6 I always wrote my apps using Sub Main as the starting point. I see in .NET I'm able to wrap it in a shared class (see [URL] for example). However, the downside is that I can't declare any class-level variables, because of course the class is never instantiated. Being shared, it limits what the code can do. So, any benefit to use a shared class and shared sub main which I'm missing here.
Otherwise it seems using a module (as in VB6) provides a lot more flexibility. Of course, I should also ask if "Application Framework" is really the way to go for real-world apps, or if it's only there for beginners and real-world coders turn it off and use Sub Main instead? If so, how are the events "UnhandledException" and "NetworkAvailabilityChanged" done if App Framework is turned off?
Often I have a list of object A, and I have another object type B that needs to hold a reference to one instance in that list. So, as far as I can imagine, it's three ways to hold such reference:
1. Make B hold the instance variable of type A
2. Make B hold some other key/ID of the A instance
3. Make B hold an integer of the list index of the A instance
I guess 3 is quite limited, and mostly suited for use locally inside a method, in a for-next loop etc. But with the other two I tend to have the feeling that I should use 2) over 1), as I believe I shouldn't "duplicate" the object.. But wonder if that is a mistake. I guess it's only holding a reference to the stack memory, so it doesn't really make any overload compared to holding just an integer key/ID..
Further my thought is that with 1), I don't have to loop through the list to get the correct instance, as it already holds it. However if A changes, it may not be reflected in B.A, if the A has been given a new instance, so then 2) would instead give access to the updated object A. So perhaps if A is a "dynamic" object that may have been reinitialized (if that's a word), I need to use method 2). However if it's a type of object that is only changed when for example the user opens a program settings form, and this setting form only changes value type variables, then perhaps 1) is appropriate?
This is kind of the case I have some times, and I wonder if I should then use 1), as it doesn't require me to loop through the list by key/ID. It makes other object hold the full reference, which is not really necessary, but maybe still more efficient? Although at the same time, maybe I shouldn't really care much about looping through an object list either, if the list is not very big.
I read a csv file into my .net program using ado.net and display it in a datagridview.In the file I have two rows. The first column is a component id, and it is supposed to be numeric. But the user can edit the csv file before having my program load it, and accidentally put text there. That is something I want to edit when he presses a button to add the data to the database. So let's say he puts a value of A in the first record and a value of 1 in the second record. Or vice versa. What is displayed in the dgv is a blank in the first record and a 1 in the second, or 1 in first and blank in second. If both csv records are A, then what is displayed in the dgv is an A in both the first and second records. I don't understand what is happening. The fact that there sometimes is a numeric in the column makes it think it is a numeric field and therefore only display numerics and blank otherwise, and the fact that there's always text in the column makes the code know it is a text field?
View 2 RepliesWhat is the difference between a local database and a Service-based database? I read the MSDN and searched the Inet.
View 4 RepliesI'm under the impression that these two commands result in the same end, namely incrementing X by 1 but that the latter is probably more efficient.If it is correct, why should the latter be more efficient? Shouldn't they both compile to the same IL?
View 17 RepliesI've developed a .NET application that, among other things, does the following:Uses WebClient to retrieve data from a remote server.
Serves as a socket server to 2 'satellite' applications run on the same machine or on a LAN.When I run the app in the VS IDE, it works great. It quickly gets the data from the remote server and communicates perfectly with the 2 satellites.However, when I build it and run it as an EXE, the response from the remote server is very slow and its communication with the 2 satellite applications become very poor.Is there some important difference between running an app in the IDE and running it as an EXE that could effect it like this?
For every member object I have to declare the variable 3 times.One in the declaration. One for property declaration. One to tell the compiler to synthesize all the function. Another one to release all those members from memory.Then I learn about Core Data. I generate diagram, poof the classes are made from me and a lot of things are done behind the screen of that visible classes.
Basically Core Data in Objective C represents some form of relational databases. Of course those databases can have relationship, including many to many relationship. The additional detail of having a third table for many to many relationship is already done.Then, there is indexed property so we can search faster. That's also done.
i am not able to use connection string?
View 1 RepliesCan anyone tell me what the technical difference is between Application.Exit() and End?Why would you choose to use one over the other, for example?
View 5 RepliesI wanted to know what (if any) differences there are to using the SQL Transaction within the application versus written into the stored procedure using TSQL statement. We would need to restructure the stored procs and vb code to get this to work and I'm not sure it would be worth the effort at this time.
Public Sub RetrieveTData(ByVal cID As String, ByVal cnn As SqlConnection) As Boolean
Dim sqlTran As SqlTransaction
cnn.Open()
sqlTran = cnn.BeginTransaction
[code].....
We aren't certain whether the timeout is occurring in DataAlreadyTransferred() or usp_BigNasty_CopyDataFromDB1toDB2 due to how the try/catch is written. We can restructure this code, but will take a week or so to get it to production (no errors occur on test/dev today)
DB1 - permanent storage, used by other applications as well
DB2 - working set, used only by Web App
DataAlreadyTransferred(cID) first checks to see if DB2 has any copies of the records, if DB2 does and those records are clean it deletes them (data could have changed in DB1 and we want the most up-to-date version). If DB2's data is dirty it is left alone and no data is deleted.
usp_BigNasty_CopyDataFromDB1toDB2 copies rows from approximately 20-30 different tables and copies over the perm copies from DB1 into DB2, essentially creating a working set from which the Web App can access
We are aware this is inefficient and are examining ways to improve it, just haven't had time yet... I believe by having the transactions in the app code it's locking many more tables than is really needed. If we move them to the stored procs, less tables will be locked at one time thus improving our chances of removing deadlock conditions/timeout issues we're seeing today. Just not sure on this..
What are the situations and their associated benefits of using Generics over Inheritance and vice-versa, and how should they be best combined?I'm going to try to state the motivation for this question as best I can:I have a class as shown below:
[Code]...
Now suppose I have a repository that takes an InformationReturn argument, that has to strore different fields in a DB depending on the type of Info object T is. Is it better to create different repositories each for the type T is; one repository that uses reflection to determine the type; or is there a better way using inheritance capabilities over/with generics?
Deviding an int by zero, will throw an exception, but a float won't - at least in Java. Why a float have an additional NaN info, while int haven't?
View 6 Repliesi have a program, three radios, and 2 check boxes. the Radios use a constant value and do a multiplication. check one applies a discount. no problem.
the last takes the values of all three radios does a comaparison and displays a label if false, performs a subtraction if true and shows savings.problem>
very convoluted using if statements. and the output is often wrong(i know this is a logic error) i can not find the fault.
would it be easier to use case statments. can and will post code if requested. as it is in if then format currently it is rather long.
Sometimes the answer is so blindingly obvious i fail to see it.
This is my problem:
<System.Runtime.CompilerServices.Extension()> _
Function CastAs(Of TSource As TTarget, TTarget)(ByVal array As TSource()) As TTarget()
Return Global.System.Array.ConvertAll(array, Function(src As TSource) DirectCast(src, TTarget))
End Function
In VB.Net you can do something like the following without any issues... just ignore the fact that this is a pretty useless class :-)
Imports System
Public Class Class1
Public Shared Function ArrayToList(ByVal _array() As String) As Collections.Generic.List(Of String)
[code]....
However if you do the same thing in C#...
using System;
public class Class1
{
public static Collections.Generic.List ArrayToList(string[] _array)
[code]....
You will get an error on the line with the return on "Collections.Generic.List" saying "The type or namespace name 'Collections' could not be found (are you missing a using directive or an assembly reference?)"I know that you have to actually have a using directive to System.Collections.Generic to use List but I don't know why. I also don't understand why I don't get the same error in the function declaration, but only in the return statement.
Edit: Just to note, the question is really about the referencing of a sub-namespace such as in the example being able to reference Collections within System.
What are the behaviors difference for the Previous Property of Other1 and Other2 Class.Note than the return type of the ovrloaded Previous Property of Other2 as bean changed to Other2 while it stay as Base for Other1.
Public Class Base
Private _Previous as Base
Protected Overridable ReadOnly Property Previous As Base
[code]....
what actually goes on inside the pc when I reference an object vs when I instantiate it.
Like this
Guys joe; (reference)
Joe = new Guys; (instantiate).So what goes on inside the computer for each line above.
Possible Duplicate: The difference between + and & for joining strings in VB.Net.In VB.NET you can use either += or &= to concatenante a string (ignoring using a StringBuilder for this question -- this is directed at a very simple concatenation).
View 2 RepliesI've been programming a custom structure to use in my program for a while now and I am debating whether I should switch over to using a class instead. Reason being is because I've read from a few sources that structures should be kept for simple storage of primitive types. However, I am using my structure to store a few integers and a few custom classes of my own.I haven't noticed any slowdowns or performance issues but I do know that I have to update the actual variables in the structures since they are value types and not reference types.
View 5 Repliesi have winsock for vb 2008 and for vb 6 but in 2008 not all commands working like Winsock1.Accept RequestID or more you dont know why ? u know i like more working in vb 2008 this is why im asking if im no have old winsock ? for vb 2008 i have there kollman koding and normal microsoft corporation COM?
View 6 RepliesI was looking around the forums for how to do a successful Winsock program but noticed that there is an alternative way of creating connections, using system.net.sockets. Would you guys say that system.net.sockets has replaced Winsock?
View 1 RepliesI am stucking this problem for long time.I am developing an IOS which to throw JSON to web service in order to insert into database.But failed to do it.
[Code]...
understanding difference between an interface and an abstract class which has no function with implementation?which is better abstract cls or interface in term of speed, features..?
View 11 Replies