I just want to ask if it is possible to create a function that accepts an expression into its arguments. Just like what IIF do. Ex: Dim strResponse as String = IIF(Msgbox("Select Yes or No", vbYesNo) = vbYes, "Yes", "No") I forgot the code, but its the thought that counts.
View 1 RepliesI want to pass an optional parameter to a function of type System.Drawing.Color. The problem I am having is that when I declare the function it says "Constant expression is required" but I have tried variations of the following, including integers, full qualified indentifiers, even old vbWhite constants to no avail.
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I am trying to write following expression on a datacolumn. But it results in error:Replicate('*', nLevel) + NameWhere: Replicate() is a user defined function (in a module). nLevel and Name are two other columns in same data table.
View 3 RepliesI want to make an numerical integration method with takes in an analytic function and integrate it over a specific interval. For the numerical integration procedure I want to use some procedures in nr.com. The problem is that these are programmed in C++ and they uses functors to pass a function to the integration method. How can I do this in VB 2010?
I want to initialize the function (i.e. set a=1,b=0 for function y(x)=a*x+b) and then pass the function to the integration method. Then when the integration method call the function it only calls the function with one parameter (i.e. x since a,b is already set)
What is the best way to do this in VB2010?I want to make a general integration method where I can pass any single valued function and integration limits.
I have just started using VB, and from what I have found so far it seems like the tools you have is
- to us a delegate for the function
- to use a lambda expression for the function
- send a pointer/adressOf
- to create a function class/structure and submit this to the function
As for now I am most inclined to create a function-class. But I am not really sure how.F.ex. I make different classes for each "uniqe function" I want to integrate, but how can I pass them to the integration function when I need to specify the argument type in the integration-function-call?This seems like a basic problem which applies to many Math operations, so I think it would be very useful to clarify this.
I want to make a GetAllContacts method which takes a sort parameter of type Func(Of Contact, TKey) which is the same type that the OrderBy method for an IEnumerable(Of Contact) takes.[code]"Too many arguments to extension method 'Public Function ElementAtOrDefault(index As Integer) As Contact' defined in 'System.Linq.Enumerable'." on the second parameter.
View 2 RepliesIm a student doing an assignment, how do i pass the value from a sub procedure to a function procedure....i want to pass the value from decSubtotal to a function procedure named CalculateDiscount; check out my code--
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I have the following Data Transfer Objects defined:
Public Class MemberWithAddressesDTO
Public Property Member_PK As Integer
Public Property Firstname As String
Public Property DefaultAddress As AddressDTO
Public Property Addresses As IQueryable(Of AddressDTO)
End Class
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1.print the cars which are fast moving cars.
i have written this code but it shows message Cannot have aggregate function in expression[code]...
Should I be concerned about the performance of the Compile method here?[code]...
The reason I want the lambda expression is because I want that function to be able to get all the way through LINQ-to-SQL to be converted to SQL. The reason I want the direct version is because I have other code that I want to validate individual serial numbers before submitting changes. And I fear that GetValidSerialNumbers.Contains(serialNumber) will execute a more-complex-than-necesssary query.
i want to set a complex column expression truncate(cdbl(Today()-date2)/30)*(parent(parentchild).field1/parent(parentchild(filed2)))but truncate function is not available !
View 12 Repliesi read an article about datacolumn.expression property here [URL]. this is really great. but i was just wondering, for my case i want to use my custom function to use in the expression. basically, on my datatable i added an unbound column AGE. when i display records, i just want the age textbox to be populated with the computation of the person's age based on birthdate.
View 7 RepliesHaving problem understanding Delegate error. Error says expression expected, How do I fix?Here is the offending line (#259)....
mylist.ForEach(Delegate Function(P As linkItem) As System.Char[] )
Here is the entire code.
<script language="VB" runat="server">
Function sectionTitle(ByRef f As String)
'Open a file for reading
[code]....
I need to execute scripted text formulas. I believe that in VB 6 and/or VBA there was a method EVAL() that did the job, eg: [Code] As it seems, such a method does not exist in VB.NET. [url] The method works fine but due to its comprehensive layout its not that fast (as i need to call it myriad of times) Does anyone have a SIMPLE, FAST, straight forward math expression method? Or anyone knows how to use the old EVAL method in VB.NET?
View 10 RepliesI have a statement:
dat.XoaNhanVien(Me.dtgcapnhatthongtin.CurrentRow.Cells(1).Value, message)
That is a function for deleting info. Now I want to create other function and get above function to parameter. I mean:
Public Function func(Byval func as " What type can be ?")
I want to pass the entire array to the next function[code]...
View 3 RepliesI'm trying to pass 2 bitarrays to a function that ANDs the bitarrays and returns the count of bits that are set to TRUE. However, something strange happens when I reference the bitarray from within the function and the results are non-sensical.
So I have output the bitarray contents before it is passed to the functionand they match the source data, then I output the contects of the bitarray from within the functiona and they are completely different.
I'm working on a VB.NET DLL right now, and one of the functions I'm writing is supposed to take a file, and clip out an array of bytes (the method I've got works, and can be abstracted away here). What's the best way to pass a file to this function? Would passing a filename to it be best, or what would be the best way to accomplish this?
View 2 RepliesI'm trying to give a default value to the register property method. This required a function, but passed as an object(delegate?).[code]....
I want to call that registerproperty method, but I don't know how I can do that in VB.net. I just need to pass along a new Person object and I thought this was the way to go[code]....
The is a calculate function for example Function Calculate (Byval v1 as integer, Byval v2 as integer, byval op as ????????) as double return v1 op v2
End Function Anybody tried this?
I don't want to use functions for every operation (multiply,divide, etc.). I wanna pass a operator same as I pass the values. How come nobody ever had this need in VB? Using enums could work but still...
i need to pass array value to a function , here are the details
function MyTest(byval a as integer, byval b() as string)
if b is nothing
msgbox("no array")
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I have an array of integers and I want to pass the array to a function that will add up the elements of the array and return the cumulative total of the elements of the array. So, if the array contains the values {1,2,3,4,5} the return value from the function would be 15.
View 2 RepliesI work with C# 99% of the time. However, I'm having to update some legacy VB.Net code and encountering an issue with VB.Net code syntax. The error that I get is "ByRef" is underlined and "Expected Expression" tag shows up when you hover over "ByRef". The "FooDetail.Load" function is written in C# and expects a List object passed as reference. Don't have any trouble using the same function in other C# classes. Can someone indicate what is wrong with below VB.Net code.
Dim FooDetail As New clsFooDetail()
FooDetail.FooID = FooID
Dim lstFooDetail As New List(Of clsFooDetail)
FooDetail.Load(ConnectionString, "Stored Procedure", ByRef lstFooDetail as System.Collection.List(Of(clsFooDetail))
The code below is used in a Linq to SQL solution, and is in the Load event of a form. It works fine to display an ordered list of people's names, and set the value member to that person's ID. However, I'm going to be using these 'people' comboboxes a lot, so I'd like to put a sub into my Utility code there is only one line in the form's Load event.
I want to call something like: Call ComboboBoxPeople(cbo, tblTurnbackMain, ReportedByID)
The sub would begin like: Public Sub ComboboxPeople(cbo as Combobox, tbl as 'sometype', fld as 'someothertype')
What can I use as the parameter types for tbl and fld?
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if this is a dumb question. I don't ever have to write anything in VB.NET.But I am passing variables named "name" to a function and sometimes it may be 1 name or 2 names, etc. I want to check in the function if its only 1 name don't add a comma, if it's 2 names add a comma. Is there a way to get how many "names" there are?
EDIT: Added my ode to make my question a little more clear. sorry for not doing it before.
My Code:Public Function GenerateCSV(byval str as string, byval str1 as string, byval str2 as string, byval GrpName as string)
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I have Listview which databound to Dataset with about 20 items per row. I have a function which executes on each ItemTemplate appearance and gets about 10 params from Eval("something"). So basically one function builds and image from 10 parameters.Instead of passing 10 Eval("something") to the function is it possible to pass it whole row and how to use this row inside of function because it is not simple DataRow or ListView row which i can access as array of items (datacolumns).Reason i do that because function looks ugly and each time i need to change it i need to deal with dozens of items.
View 2 RepliesIm having a very difficult time trying to pass an vba array ive built from ms- access vba to a .net function.I don't have a com problem I can reference the library just fine from vba but and i can call a simple function from vba. however my problem exist when i attempt to try to pass an array to the vb.net function. vb.net code
View 3 RepliesCan we pass parameters to a function using delegates
Private Sub UpdateLabel(byval text as string)
If Me.Label1.InvokeRequired Then
Me.Label1.Invoke(New MethodInvoker(AddressOf UpdateLabel))
Else
Label1.Text = text
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I have a variable that I am trying to get to iterate up by one, i.e. X starts at 0 x+1 on first pass thererfore its at 1 then x+1 on second function call therefore x=2 and so on. I've tried the different loop and for commands but I cant get one to stay until the next function call, does it need to be a global variable? I'm sorry if this is in poor form or improperly formatted, definently trial by fire going into the object oriented world.
View 9 RepliesI'm trying to pass a callback function from a C++ dll to a VB.NET application.Here is my current C++ code :
void DLL_EXPORT registerEvent( void (*callBackFunction)(string str),string str)
{
callBackFunction(str);
}
void test(string str)
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Can I pass a form as a parameter in a sub like public Sub GetData(Byval Frm as form) and access its controls?I have few forms (you can say: FrmAccounting, FrmEngineering, FrmIT) with almost the same controls in each of them (txtEmployeeID, txtEmployeeName, optMale, optFemale etc), where no two forms are open at same time, and each of those forms have a Button which opens a new Form (you can say FrmCollectData) now I want to fetch data in FrmCollectData depending on which form it was opened from.. like if user was on FrmEngineering and it clicks button to open FrmCollectData.. form collectData fetches data from FrmEngineering Controls and if user was on FrmAccounting and it opens FrmCollectData, form Collectdata fetches data from FrmAccounting..
earlier, in VB6.. In one of the Sub written in frmCollectData I checked which form is opened by setting flags in each of forms (frmEngineering, frmAccounting etc) and then I passed the same form in a sub which writes data in frmCollectData controls.. but am not able to do the same in VB.NET.