I'm trying to use Excel-DNA to integrate my VB.NET DLL into VBA. But I'm running into the following problem. If I try to add this line before one of my static (Shared) class functions:
<ExcelFunction(Description = "Do stuff", Category = "Useful functions")> _
I get a compile error saying "Name 'Description' is not declared" (and same for Category). I've got VS2005 so maybe that has something to do with it. The example given in the Excel-DNA documentation is for C# and I'm feeling that maybe I just need to get the syntax right.
I've got the needed
Imports ExcelDna.Integration
line at the beginning of my file.
The syntax for using attributes in VB.NET is a bit different to C#. You need to write the property assignments with ":=", something like this:
<ExcelFunction(Description:="Do Stuff", Category:="Useful functions")>_
...
Related
Does anyone know how to put the enableCors into the controller on vb.net. i am working along with a pluralsight course and tried a code translator with no luck. my attempt is below.
<EnableCors(origins: "http://localhost:53080", headers: "*", methods: "*")>
The correct syntax would be something like this:
<EnableCors("http://localhost:53080", "*","*")>
The C# example appears to use named parameters. VB.NET supports that too, however the EnableCorsAttributes has properties and contractor arguments that only differ by letter casing. This confuses the compiler as to whether you are attempting to set the named parameter or the property in the attribute. So, in this case we can just drop the named arguments all together.
In Vb.net this <EnableCors("http://localhost:53080", "*","*")> will work, but, you have to add on NuGet the Microsoft.AspNet.WebApi.Cors and Microsoft.AspNet.Cors. You need to add Imports System.Web.Http.Cors on the class.
Remove any empty line between the http://localhost:53080", "*","*")> and the declaration of the controller class.
I have researched and it seems that most is bouncing around the problem I have.
#Code
#Imports System.ComponentModel
Dim values = New SelectList([Enum].GetNames(GetType(myEnum)).GetAttribute<DisplayAttribute>()
End Code
The last pararenthesis has a blue line under it and when hover tells me an expression is expected. I want to capture the display name from my enum and have tried many things found on the google search without success. Why am I getting the expression expected error?
Attempted to incorporate and now getting at end parenthesis
Dim type = typeof(MyEnum) ls is expected.
You might want to have a look at this awesome NuGet package called UnconstrainedMelody from Jon Skeet.
https://www.nuget.org/packages/UnconstrainedMelody/
Helpful static methods (or extension methods) for enums and delegates, with constraints which can't be expressed in regular C#.
Have a look at the functions UnconstrainedMelody.Enums.GetNames() and UnconstrainedMelody.Enums.GetValues()
Im trying to use the ComAutomationFactory class in VB .NET the example im working from is c# and is working fine but my project doesnt compile and says this class is not defined??
also what is the return type? in the c# example it returns a type of dynamic but this type does not exist in vb .NET?
Possibly you're sample is old, according to this blog:
http://silverlight-essentials.blogspot.com/2010/03/breaking-changes-in-com-interop-between.html
It's changed name as:
The class ComAutomationFactory has been renamed to AutomationFactory.
Additionally you have to reference System.Runtime.InteropServices.Automation for this class.
Regarding the return type, the answer to this question has a solution:
Iterating over Word Document Fields using ComAutomationFactory in Silverlight 4
I need some help with a LINQ query in VB.Net, please.
I have this simple group statement:
Dim drivers = From d In DriversOwners _
Group d By Key = d.UnitNumber Into Group _
Select Key, DriverGroup = Group
This works, and returns me the data I need to work with. Now I want to iterate through the groups, using a For Each construct. like this:
For Each x In drivers
Next
However, the compiler is barking at me, telling me that the
"'x' is not accessible in this context because it is 'Friend'."
Anyone know what I am doing wrong here?
Thanks in advance.
After digging and digging, I finally found the answer to this problem. Talk about obtuse!
Enabling LINQ in a .NET Framework 3.5 Project
When you move a project to .NET
Framework 3.5, a reference to
System.Core and a project-level import
for System.Linq (in Visual Basic only)
are added automatically. If you want
to use LINQ features, you must also
turn Option Infer on (in Visual Basic
only) [my emphasis].
When I changed the target framework from 2.0 to 3.5, Visual Studio automatically added the System.Core assembly, and automatically imported the System.Linq namespace. Now why in the world did it not also set Option Infer to "On" as well?
http://msdn.microsoft.com/en-us/library/bb398197.aspx
Looks to me like the variable x was declared earlier - as a class field, a method parameter, or a local variable.
Am I right?
I'm not sure if you've solved this or not. I had the exact same problem today and what ended up working for me was to not use a single-letter variable in the For Each loop. My code was the same as yours:
For Each x In a
...
Next
When I changed the code to the following it worked:
For Each retVal in a
...
Next
I also found the same 'Friend' error behavior for any single-letter variable.
I have no idea why it behaves this way, but I thought I'd pass this along in case this question is still out there.
Using VB.net, the following snippet gives the error below.
Dim _account = Account.Find(Function(x As Account) x.AccountName = txtFilterAccountName.Text)
or similarly if I do
.SingleOrDefault (Function(x As Account) x.AccountName = txtFilterAccountName.Text)
will both give the error "The method 'CompareString' is not supported". If I make the same call searching for an integer (ID field) it works fine.
.SingleOrDefault (Function(x As Account) x.Id = 12)
So integer matching is fine but strings don't work Is this a problem with the VB.net templates?
No this is not a problem with Vb.Net templates.
The problem is that you are not using a normal LINQ provider. Based on your tag (subsonic) I'm guessing you're using a LINQ to SQL query.
The problem is that under the hood, this is trying to turn your code into an expression tree which is then translated into an SQL like query. Your project settings are turning your string comparison into a call in the VB runtime. Specifically, Microsoft.VisualBasic.CompilerServices.Operators.CompareString.
The LINQ2SQL generater in question or VB compiler (can't remember where this check is done off the top of my head) does not understand how to translate this to an equivalent bit of SQL. Hence it generates an error. You need to use a string comparison function which is supported by LINQ2SQL.
EDIT Update
It looks like the CompareString operator should be supported in the Linq2SQL case. Does subsonic have a different provider which does not support this translation?
http://msdn.microsoft.com/en-us/library/bb399342.aspx
The problem is with SubSonic3's SQL generator and the expression tree generated from VB.NET.
VB.NET generates a different expression tree as noted by JaredPar and SubSonic3 doesn't account for it - see Issue 66.
I have implemented the fix as described but it has yet to merge into the main branch of SubSonic3.
BlackMael's fix has been committed:
http://github.com/subsonic/SubSonic-3.0/commit/d25c8a730a9971656e6d3c3d17ce9ca393655f50
The fix solved my issue which was similar to John Granade's above.
Thanks to all involved.