Difference Between (OrElse And Or) And (AndAlso And And)?
Dec 7, 2011
What is the difference between (OrElse and Or) and (AndAlso and And)?Is there any difference in their performances, let say the correctness benefit?? Is there any situation that I shoudn't use OrElse and AndAlso?
If I have the following a OrElse b and a is True then clearly b is never evaluated. But if I add an Or, then what?a OrElse b Or c
Does/should c get evaluated? And what if I put in some brackets?Apologies if this is basic. Of course I can test for the answer myself but I can't find this question answered here or elsewhere. Lots of questions dealing with Or versus OrElse but nothing dealing with Or with OrElse
I'm having problems with the following Linq query (demandNb is a filter option, as a string):
[Code]...
My goal is to get all demands for the database if the filter fields is empty. If there is a filter, the function should return all demands that match the filter. Currently, when I try to convert the IQueryable collection to a list using .ToList(), the following error is thrown: Conversion from string "" to type 'Double' is not valid.
When writing an If statement, I've always used And when needed like: If 1=1 And 2=2 Then. The only time I ever used AndAlso is if the second condition will error if the first isnt true like: If Not IsDbNull(Value) AndAlso Value=2 Then. However, recently I've heard that AndAlso is better for performance than And as the second condition is only read when the first is true. In this case, should I always just use AndAlso?
Im trying to check service on a remote server.. as i was typing this i kept getting a syntax error on AndAlso statement.
Also, how do i add the path to connect to a remote server to check the service?
Private Sub CheckServiceButton_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CheckServiceButton.Click ' This will check if the service is running '
Looking at the following code snippet in VS2008 (this is from the SBS book)
Dim HumanAge As Integer = 0 If HumanAge <> 0 And 7 / HumanAge <= 1 Then MsgBox("1 dog year or older")[code]....
I expect to get a runtime error, because And evaluates both conditions, which is why in this case AndAlso should be the better operator to use. When I try this code there is no difference in behavior between 'And' & 'AndAlso'. In neither case I get a runtime error, not even when I flip the conditions around. Is this by design, a lucky accident, or do I just not get it?
The below query fails with Null Reference Exception when there are elements in BOMIDs where MatID property is nothing.I thought the 'x.MatID isnot Nothing AndAlso' would prevent the x.MatID.Process part of the where from being executed. There are a couple elements in the BOMIDs collection that where MatID is nothing.
From x In BOMIDs _ Group Join y As PurchasedProcess In SpecialProcesses _ On x.MatID.PurchasedProcess Equals y.Name _ Into G = Group _
My doubt is about OR and ORELSE. There is any situation where OR is better to use than ORELSE ? And if not, why they don't just "upgrade" de internal code ?
I'm sure this is straightforward but I cannot find the correct string to get a google result. In VB.NET what is the difference between = (equals sign) and := (colon followed by equals sign)?
know the difference between C#.Net and VB.Net. I use C#.Net for my projects, but when ever I met with some other programmers they often called VB.Net more powerful and easy, than C#.Net. I always asked them "Why it is more powerful then C#, since it uses the same framework?" but still I didn't get any answers.
what exactly distinguishes a COM component from a DLL? Isn't a COM component just a library of functions that can be called from another application? Why is using a COM component so much more complicated than just registering it like one would do with a DLL?
I was under the assumption that VB's For Each loop was the same as a For Next loop. But when i try running the following code I do not get the expected result.
For those who have experience, working with VB.NET, it's easier to use SlimDX or SDL? The tutorials for SlimDX are already written for .NET, but I've read that SDL it's a lot easier than DirectX itself.in my case, I just need 2D graphics.
What is the major difference between 'for each' and 'for' loops in .NET? Is there any performance gain while comparing these two? Which one gives a better performance/faster/memory management?
I have in the past used .net executables as libraries. I'd just add them to the references in visual studio and I was ready to go. Today I tried the same to a new exe (actually mine) and it doesn't seem to work. When I add it to Visual Studio and try to watch its members on the Object Browser, it doesn't show up anything inside that executable's assembly.
I know the main difference between an exe and dll is that the first has an entry point while the 2nd doesn't. Are there any more differences? I know that unmanaged dll's also have a DLL entry point, do .net have one too?Also, what might be the reasons that could make my standard exe/dll (with this i mean, not obfuscated or anything extreme like that) not show up anything in the Object Browser?
What's the difference between / and for division in vb.net? My code gives very different answers depending on which I use. I've seen both before, but never knew the difference.
I am trying to find the difference between two dates. The first of the two dates can be changed and when it is changed, the difference between the original dates has to be retained. This means that I have to automatically change the second date to have the same difference in days as it did before, but with a new first date. [code]I have the value of the old date1(currDate) and the new date1 value(newDate). I need to get the difference between these, and then add or minus these days from the endDate.
I'm making a form with an overview of orders from our clients. I have inserted 2 datetimepickers so the users can choose a period.
To know how many cols I need in my grid, I need to know how many months there are between the 2 datetimepickers. But that seems to be the problem. How do I get the number of months starting from one datetimepicker untill another.
I am a VB programmer working my way into C#. I learned how to create and raise events in vb and am finding that it isnt done the same way in C#. Has anybody come across an article that will help me to understand how to do events in C# and maybe explain why it is different in VB.