I have a dataset connection to an MS Access database. I want to use IN operator in WHERE clause like: WHERE DepartmentID IN (1,2,3)This means that all record with an ID of 1, 2 and 3 will be filtered. But the problem is I cannot create a parameter like:
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I am trying to design a Function/Sub that will need to accept a variable number of parameters. Catch is that the parameters being passed are arrays themselves. As i understand it when you pass a variable number of arguments to a method, you pass them via an array. What im looking for is to make a method that would accept this form:
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I want to query items from countries that are selected from a treeview (with checkboxes). However the number of countries that is selected by the user is not known beforehand. So how can I make a proper query when the number of OR operators is unknown? For example: SELECT DISTINCT Item FROM Countries WHERE Country LIKE @c1 OR @c2 OR @c3 etc� and then add the parameter values based on the selected countries in the treeview. I looked into parameter arrays but can�t make sense out of it really
View 13 RepliesBanging my head against a wall here. I have a query that looks like this.
SELECT FirstName, LastName, Address
FROM Members
WHERE FirstName LIKE 'JOE%'
That works absolutely fine in query wizard and the DataTablePreview data window. However, when I do this.
SELECT FirstName, LastName, Address
FROM Members
WHERE FirstName LIKE ?
I get nothing when I run the fillby method. If I change the LIKE to =.
SELECT FirstName, LastName, Address
FROM Members
WHERE FirstName = ?
Everything works great. I need to get LIKE working though so I can wildcard search.
I'm using the SQL server OLE db connections if that means anything.
UPDATE
Using the LIKE operator doesn't work at all. When I just swap out = for LIKE. Nothing is returned.
I'm looking at inherited code and I found this in a vb.net windows form:New System.Drawing.SizeF(6.0!, 13.0!)My question is, what is the significance of the ! (exclamation) operator here? Most of my searching for the exclamation operator ends up returning recordset format or the ! gets ignored in the search and I get hundreds of unrelated items.
View 4 RepliesOkay, I am TOTALLY confused here. I have a class... say MyClass. It has several properties of another class of my type, say MyHelperClass (along with other properties).
I am doing the following:
Dim inst As MyClass = New MyClass() With {
.p1 = sv1,
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Let's say we have the following
Dim number1 as double = 2.24
Dim number2 as double = 12
Dim symbol as string = "-" (or "+" or "*" or "/")
How is it possible to execute this operation using the operator from the variable?
Is it possible to use "IN" operator together with OleDbCommand.Parameters.AddWithValue ?
I am using Visual Studio 2008 and Microsoft Access 2000.
I have search online but find no solution on it. Below is my code:
Dim conn As New OleDbConnection
Dim cmd As New OleDbCommand
Dim Adapter As New OleDb.OleDbDataAdapter
Dim strSQL As String
Dim dsDoc As New DataSet
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Where there is 2 Document No inside parameter @Doc , i can't get any of them. When there is only 1 Document No, then it is ok.Is it possible to use "IN" operator together with OleDbCommand.Parameters.AddWithValue ?
Syntax error (missing operator) in query expression 'Serial Number = 'L3FW341''.The Serial Number field is declared as text in Access Db.
I am not sure which operator is missing in my command!Below is my code:[code]......
Is it possible to make Color variable parameters in custom classes Optional?Everytime I try, it gives me a "Constant expression required" error.[code]
View 2 RepliesIs it possible to have a class, sub or function declared with an arbitrary number of parameters? And those parameters be a type, like generics? For example
vb.net
Public Class Test (Of T1, (Of T2))'The (Of T2) means that after the first parameter can be an arbitrary number of parameters
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I am getting Errors: Operator '<' is not defined for types 'System.Windows.Forms.Button' and 'Integer'.
Operator '>' is not defined for types 'System.Windows.Forms.Button' and 'Integer'.
Value of type 'Integer' cannot be converted to 'System.Windows.Forms.Button'.
And my program does not work!
Below is my code..............
Private Sub ProgressBar1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ProgressBar1.Click
ProgressBar1.Value = TextBox1.Text
End Sub
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Is there a way to create a method with unknown number of parameters? And if it this the case: How is it possible to get access to them within this method? Do they have to be from the same type?
View 1 RepliesIn the example below, what would you name the parameter given that it is used to initialize the property FromDate?For class constructor methods, I like to have the name of the constructor parameter variable match the name of the property which is being initialized. For example, the parameter "fromDate" is used to initialize the module level variable "_FromDate" with the statement _FromDate = fromDate. Likewise, I could have alternatively written Me.FromDate = fromDate.
Proponents of C#'s case sensitivity would probably say that using a leading lower cased letter for the param variable name, which I believe is MS convention, is an acceptable approach to distinguish it from the Property of the same name but different casing.
However, VB is not case sensitive, which I generally appreciate. In the following example, I am using a param name that matches the property name, 'fromDate," and VB refers to the local instance when there is ambiguity. However, many would probably argue that this "ambiguity" introduces the opportunity for the developer to get confused and not realize which variable is being used. For example, my intent below was to have TWO params passed in, "fromDate" and "toDate" but I accidentily ommited one and as a result, the VB.NET did not warn me of the mistake because it assumed that the statement _ToDate = ToDate was equivalent to _ToDate = Me.ToDate instead of informing me that the variable on the right side of the assignment statement was undeclared.
Public Class Period
Property FromDate As Date
Property ToDate As Date
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In my judgement, we should have a convention for prefixing all parameter variable with a prefix, but hasn't the use of prefixes been discouraged by Microsoft? For example:
Public Sub New(ByVal paramFromDate As Date, paramToDate As Date)
..or maybe it could be shortened to pFromDate, pToDate...
I 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#?
Dim x = GetType(List(Of )) 'valid statement
Dim list As New List(Of String)
Now I want to see if list is a List(Of T) variable: Dim isList = TypeOf list Is List(Of ) On the last line I get a compile error: "Type Expected". Is there any cheap-performance TypeOf operator alternative for generics?
I'm currently working with a client's VB.Net code, which was developed for them by a small development shop a few years ago and which they purchased and have been maintaining and uprgrading since. This client's primary developer is out on indefinite (likely permanent) medical leave and I'm now filling in until they bring in a full timer (as I'm a contractor here). My current task is to add some functionality to a the VB.Net code they purchased. I'm finding practices and techniques in the code that absolutely baffle me and can't make the code do what I want. I'm starting to wonder if it's me and was hoping to get some thoughts on the code I've encountered.
For example: Setting a variable to accept the result of a function by calling the function with many parameters, clearing the parameters in the function, setting them to some value, calling another function with those new values, then never using the values returned by the functions. I'll add a code snippet in the first comment since this is already getting long.
i have this variable Dim odddivider2 As Integer = CInt(20 6) and i want to expand the number 2 like a variable from 2 to 4.5 how i have to make that
View 14 RepliesI have 10 variables that have numbers at the end in sequential order (e.g. V1, V2, V3, ect.). I would like to perform a function to find what the position is in an array and then add then add the value to the correct variable. Can I combine V & and the number to manipulate the variable?
View 2 RepliesI am making a simple console game. If you have ever heard of the board game code breaker you will understand better.
In my version of the game you will have to figure out a four number combination. The only numbers it can be is 1, 2, 3, or 4.
I need to generate four random numbers and put each on into its own variable. This allows me to call back each number.
How do I do this? I have been doing some research on random numbers and I use this code to generate four random numbers
Dim rnd As New Random()
Console.WriteLine("20 random integers from -100 to 100:")
For ctr As Integer = 1 To 20
Console.Write("{0,6}", rnd.Next(-100, 101))
If ctr Mod 5 = 0 Then Console.WriteLine()
Next
Console.WriteLine()
But I can't figure out to put each number into a variable so I can call the same numbers back.
If i have a variable '12'
and a variable 'hello'
how can i double the '12' each time the variable is used?
What im trying to do is have a textbox which the user writes in a number, the number they enter then determines the amount of times a variable is written in a textbox.
so if the user were to put '3' into the textbox and click go, it would print hello12hello12hello12, how can i increase the number 12?
what i want it to do is look like this when the user presses go: hello12hello24hello36
How can I get a Variable's value set to the number of Data Fields in my DataBase that is NOT Nul.
I have in a table 10 fields or columns Named: Ing1, Ing2, Ing3, Ing4, Ing5, Ing6, Ing7, Ing8, Ing9 and Ing10. This fields will all most never all be fild, will be fild from 1 upwords. I need to know how many of them is NOT Nul.
I have a button that searches through a binary file to bring up customer information with the following code:
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My problem is, I need to create a variable which holds the record number, so that the record can be edited, and put back into the file at its previous location, how would I implement this? Not sure about the code.
I'm developing an app that should allow the client to add several content sections to a page (in tabs). However I haven't found a way to easily create a form for editing the tabs.Assume for now that a tab just contains a title. I have a form that adds a tab, that's simple. But I also want a form that displays a text input for each tab and allows the titles to be edited and saved. I'm struggling with two main concepts:How to dynamically display the fields after grabbing the tab data from the database (each tab has its own row in the table).How to loop through the submitted data and update each tab in the database.How to select a particular text field from the number (e.g. given "1", how to select the element with ID "TabTitle_ 1".[code]I thought something like TabTitle[0] would be acceptable and allow for easy looping (as it does in PHP) but it's "not a valid identifier" apparently.It's very possible I have the approach completely on its head.
View 1 Replieshave code to generate a new random number as follows (which is 100% working and generating numbers between 0-9:
Dim randomNumber As Integer
Dim randomNumber1 As New Random
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as the title suggests i am trying to save a randomly generated number to a variable.I have done:
Dim randomposition As Integer
randomposition = Rnd(1, 1000)
when i do this it gives me this error:
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I have a variable called VarNUM which stores a number from 1 to 10. What i want to do with this is based on the current number stored in that variable call a different set of variables from a module with Public Structure ITEM1. It has the same set of variables for ITEM1 - ITEM10 but with different values. So ya in raps how can i use the number in one variable to access a set of different variables? Something like ITEM(VarNUM) then the set of variables that all have same name but with different values so that i dont have to go,
Code:
if VarNUM = "1" then
name = ITEM1.name
store = ITEM1.store
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Variable 'RandomNumber' is used before it has been assigned a value. A new reference exception could result at runtime.
Sub RandomizeConLandLaunch(ByRef con As Integer)
Dim RandomNumber(,) As Integer
ConLandLaunch(con) = RandomNumber(1, 30000)
End Sub
what should i do ?