I saw this in some vb.net source code:Dim sTest As String = "" & drTest("column")
I was told that if drTest("column") is nothing, then sTest will be assigned "", so it is in effect doing:
Dim sTest As String = If("",Nothing,drTest("column"))What is the downside of doing it the first way I showed?
What is the difference between using If and IIf?
In Perl (and other languages) a conditional ternary operator can be expressed like this:my $foo = $bar = $buz ? $cat : $dog;Is there a similar operator in VB.NET?
View 2 RepliesI am looking to make this statement work in a VB.net page:
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The ternary operator is causing a error: Compiler Error Message: BC36637: The '?' character cannot be used here. I want to use a tenary operator to display text based on the the field Inactive containing a true or false text value.
I'm usually reasonably good at translating C# into VB, but I'm a bit stuck partially due to the ternary operator in this function and also because I don't fully understand what is happening with the "from x in dataSource.OfType<object>() select 1).Sum()"
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Lambda expression with ternary operator in VB?
View 15 RepliesI'm having problems with a Nullable DateTime in VB.NET (VS 2010).
Method 1
If String.IsNullOrEmpty(LastCalibrationDateTextBox.Text) Then
gauge.LastCalibrationDate = Nothing
[code].....
Suppose we have a nullable value in vb.net: Dim i as Integer? We want to assign a value to it, basing on a condition, and using a ternary operator, because it's so neat and stuff: i = If(condition(), Nothing, 42) That is, if a condition is true, employ the null-ability, otherwise the value. At which point the shooting occurs. For no apparent reason VB compiler decides that the common base type for Nothing and Integer is Integer, at which point it silently translates the statement to: [Code]
View 5 Repliesdim val1 As Integer? = If(5 > 2, Nothing, 43)' val1 = 0 dim val1 As Integer? = If(5 > 2, Nothing, Nothing)' val1 = Nothing What gives? Is this a bug, or am I overlooking something?
View 1 RepliesI am having a weird problem. IIf is messing up when I am working with an array. Apparently it is checking my else statement even though it isn't activated. Here is some code that demonstrates the issue:[code]
View 2 RepliesThe following compiles in VB.NET (with Option Strict On) and outputs False:[code]Why does that work?The documentation clearly states that the three-argument version of If requires a Boolean as the first parameter:[code]So, why does this work? Is it a bug (or "hidden feature") in the compiler or is it a bug in the documentation and Boolean? is actually a valid type for the first argument of If(a, b, c)?In C#, b ? x : y does not compile if b is of type bool?.I've reported this issue to Microsoft Connect. Someone from MS has replied and confirmed that the documentation will be updated to include the Boolean? case.
View 4 RepliesIf you assign a value to a nullable integer via a ternary operator, it can't become null..While this question may seem like a duplicate of many, it is actually being asked for a specific reason.Take this code, for example: Dim n As Integer? = If(True, Nothing, 1) In that code, the ternary expression should be returning Nothing, but it's setting n to 0. If this were C#, I could say default(int?) and it would work perfectly. Now it looks like I am going to have to ditch the ternary and use a regular If block, but I really want to use the ternary. If Nothing were truly VB.NET's equivalent to C#'s default, how can you explain this behavior?
View 1 RepliesI am tightening up my coding with the Option Strict set to ON. It has now produced alot of errors. An example of this is:
If AllocatedDGV.Rows(i).Cells("RoomNumber").Value = RoomsAvailableDGV.Rows(j).Cells("RoomName").Value Then
It gives me the following error: Option Strict On disallows operands of type Object for operator '='. Use the 'Is' operator to test for object identity.
I need to write an interface to get data to/from our data files.
We have a low level class that holds field values for each record read from the files.
This just holds two values, the value read from the file (DBValue) and the updated value that may need to be written back to the file (CurrentValue).
These values may be any of the standard value types (integer, date etc) or a string.
Either value (DBValue or CurrentValue) may be null if not defined.
I have written the class to manage this data which works fine while option strict is NOT on.
But we have an office policy of having option strict on all the time.
When I put option strict on, my object value comparisons fail with the error: "Option Strict On disallows operands of type Object for operator '='. Use the 'Is' operator to test for object identity."
Question, how should I change the following code to handle option strict on ...
This is all running on Visual Studio 2010
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Possible Duplicate: Is there a conditional ternary operator in VB.NET?
Can we use Coalesce operator(??) and conditional ternary operator(:) in VB.NET as in C#?
I know how to check whether an item exists in a list using (MyList.Contains), But I do not know how to check the whole list. For example (use one button and one richtextbox):
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I want to perform equality comparison in VB.NET and cannot get it to work. Error: value of type Boolean can not be converted to System.Drawing.PointF
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Also, if they are so similar then why do they exist separately?
View 3 RepliesIs there an API or something I can use similar to PrintScreen?
I want to be able to select everything inside of a panel and then print it.
I've two BGW with similar coding but different approach, My second BGW shows me "NOT RESPONDING" whenever i try move/click/focus to form while the BGW is running.
VB
RichTextBox2.AppendText("Some Text")
process2.ReportProgress(inc)
My.Computer.Network.DownloadFile(andpic, "pics/" & spliti(0) & nnum & ".png")
My.Computer.Network.UploadFile("pics/" & spliti(0) & nnum & ".png", "ftp://ftp.mywebsite.com/domains/mywebsite/public_html/Pics/" & spliti(0) & nnum & ".png", "users", "password")
WebBrowser1.Navigate("Mywebsite")
I've taken out number of things that i think is causing this error Are they the cause of "NOT RESPONDING" ?
I have a web site where users enter company names to use in the rest of the app. However, recently I've noticed that similar duplicates are appearing, e.g. someone will enter EastTec Solicitors another will enter EastTec Solicitors Ltd someone else will enter EastTec Solictors (missed the i out in Solicitors), when there should only be one entry of EastTec Solicitors. What is the best way of checking the database for entries similar to what they have entered? How would you about checking for spelling mistakes as well like the Solicitors one?
View 7 RepliesWhat is a good way to do networking? I tried this example, but it did not work. [URL]
how to connect two computers similar to how you would with Winsock. Also, I would like to be able to send an image, but I can figure that out later.
What I need to do is be able to enumerate pretty much all hWnds and locate any TextBox (outside of my program) and get information about it (eg: Name if any, text in it, etc).
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I'm developing a program that is similar to ATM but I can not keep track of various clients so that each may have their account
View 7 RepliesI've been using the 2006 SerialCommChat program to do my programming functions.This only has CommPort availability and I'm needing both Commport and what I guess they call a Virtual Port known as the USB Ports.
View 5 RepliesI'm trying to create an enumerable class, similar to System.Drawing.Color - My goal is to have places in the code where I can define a variable as the type of my structure, then be presented a list of static values to pick from.I'd also like to use this for a property of a UserControl.I don't know if I'm using the right setup here with the class, structure, etc.I'm just trying to mimic the Drawing.Color class.I'm creating a Public Class called Person.Inside it, I have two Public ReadOnly Properties for Name and Age, their corresponding Members, and a Constructor to create a new Person.Second, I have a Structure called Persons and it has two ReadOnly Properties: Billy and Sally.[code]In my attempt, I get the full freaking .net class library in my intellisense list. Using Drawing.Color, I get a nice pre-defined list of values to pick from.No extra methods.No constructors.Just values.
View 16 RepliesIn VB.NET, I am trying to talk to a webservice (that can't be changed) to create and update customer data.The CreateCustomer service expects an object of type ConsumerPerson and the ChangeCustomer service expects an object of type ChangeData.The properties of these two object are exactly the same, so I thought it would be wise to just set the properties using one single function.
View 5 RepliesIn Visual Basic I used to use the Mid function to loop through a string and examine each character, i.e. like this:
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Question is, how would I go about doing something similar using Java?
I want similar coding for treeview, where for linklabel is as follows.
Private Sub LinkLabel8_LinkClicked(ByVal sender As System.Object, ByVal e As System.Windows.Forms.LinkLabelLinkClickedEventArgs) Handles LinkLabel8.LinkClicked
WebBrowser1.Navigate(Application.StartupPath & "\source\test.html\")
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I've looked around and I haven't found anything that fits my needs.I wish for the program to be able to intercept the Win32 (?) messages that are being sent to my own application, which is written in Visual Basic.As a side note, is "intercept the Win32 messages" the correct phrasing?Either way, an elaboration won't hurt; I wish for the spy tool to intercept the same messages that I would programmatically intercept with WndProc, i.e: the SendMessages and PostMessages.
I wish to make it clear that I am not seeking a program that intercepts the .NET framework events.
Edits:I can see my window and the handles of its child controls, but I do not receive any messages.I am using Windows 7 64 bit.My Spy++ version is 8.00.50727 Semi-solved; I have got a Spy++ alternative ([Window Detective][1]) to work on my virtual machine, which I am most certainly happy with, and would definitely not mind settling for. Although I am still wondering why all the "spy-like" programs I found did not work on my "main" PC... but I guess I needn't care.
Like my computer have 3 image, and this is the location of these 3 image:
C:/A.jpg
C:/B.jpg
D:/C.jpg
And this is the 3 image preview: now if we use eye common sense, we will saw that A.jpg is similar with C.jpg (just think that C.jpg is not animated) But now if i use VB.net to find the for the similar image, how can this be? (just like the searching function on computer but this is searching for similar images, and also what google images does (google image have a function that search for similar images))