Declared Variables With SQL Statement?
Aug 20, 2010
I have a simple table in an access database that I'm using in a VS2010 project. I have a combobox control that a user can select the horse power of a motor. I then take that selected value from the control and copy it to a string variable called gstrSelectedHP. All I want to do is run a query that will pull up the full load amps of that horse power motor from the table. I have the query already, but I need to somehow put the gstrSelectedHP in the WHERE part of the query so that it only returns that value.
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Dec 8, 2009
Recently started swicthing our project from 1.1 to 2.0 framework:
getting lot of errors:
Saying VBNullString is not declared
If ScanString <> vbNullString Then
Stored = ScanString
End If
[Code]....
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Dec 16, 2010
I'm trying to create a generic Controller Class for generic events. But these these events still need to access their class variable. So my idea is to create the Base Controller Class with a ModelBaseclass variable as _ClassVar, which is inherited by all of the other class Controller classes will derive from. But I want the derived controller classes to override the _ClassVar with whichever one they need.
I want to do this, so the ControllerBaseClass can have all the generic functions that all the Derived Classes would use.
Model :
Public Class ModelBaseClass
Public Overridable Function Foo() As String
Return "Name"
[Code].....
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Jul 15, 2011
I have a list of variables that are being created on one line.
Dim strFirstname, strMiddleName, strLastName As String
Is it possible to set the values for all of them at once? I know this doesn't work, but this is what I'm trying to do :
Dim strFirstname, strMiddleName, strLastName As String = ""
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Apr 23, 2009
I have the following code and i do no know why the program tells me that the variables are not declared.
[Code]...
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Sep 4, 2011
I have declared 2 variables as Double in my VB Code. Example:[code]Somerwhere down the code, after some internal calculations, the variables A1 and B1 have attained new values. Example:[code]Do I need to do a conversion of some sort in my program codes ??
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Sep 30, 2009
I am trying to bind a few values in xaml to variables declared in the code behind.
e.g.
vb.net
dim test as integer = 2
[code]....
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Jul 29, 2010
how variables declared with protected access in a base class are used to implement inheritance.
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Jan 18, 2010
when we have a method of a derived class implementing a method of an interface which is already implemented in the base class, the compiler throws a warning (by default). when i see a warning i will try to erase it and the only way to erase this warning is to mess with the settings of the compiler hence i hope that there is a way to declare "how" a method implements an interface's method. by this i meant that we should be able to declare overridable, overrides and shadows for the implements keyword. hence if we declare overridable-implement for a method of a base class implementing an interface's method, the compiler should give no warnings when we override this implementation (re-implementing in a derived class). Similarly, if the method of the base class implementing an itnerface's method was not declared as ovveridable-implement, the derived class should be able to Shadow the implementation example code which flags unnecessary warning:
[Code]...
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Jun 3, 2009
In re-engineering a windows forms application, I find that a lot of code-behind in the various form classes is duplicative and I'm trying to centralize as many procedures as possible into a base class which can be inherited and used by the subclassed forms.
This process seems to be going well and is making the code in my subclasses much simpler and hopefully easier to maintain, but I'm not sure where to draw the line between leaving code in the subclasses and engineering for generic resusability and moving it to the base class.
Specifically, in some subclasses I have code which manipulates variables and objects specific to the subclass, and although I could move the code-behind into the base class, the base class code references specific objects which are needed to compile. For example, each subclass manipulates a databound datagridview and form detail controls which allows the user to select between multi-record and detailed single-record views of a datatable.
In Visual Basic 2008 do I need to declare dummy data objects in the base class so that the base class will compile? Or is there a way to indicate that the data objects will be provided by the subclass?
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Apr 16, 2010
[code]How do I use variables in a SQL statement?
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Apr 16, 2010
I got this in my SQL statement. I "BOLDED" the problem.SELECT OrderID, CustomerID, EmployeeID, OrderDate, RequiredDate, ShippedDate, ShipVia, Freight, ShipName, ShipAddressShipCity, ShipRegion, ShipPostalCode, ShipCountry FROM Orders WHERE CustomerID =@CustomerID
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Apr 16, 2010
I got this in my SQL statement. I "BOLDED" the problem.
SELECT OrderID, CustomerID, EmployeeID, OrderDate, RequiredDate, ShippedDate, ShipVia, Freight, ShipName, ShipAddress, ShipCity, ShipRegion, ShipPostalCode, ShipCountry FROM Orders
[code]......
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Nov 4, 2010
I have a VB .net application which works fine on a 32 bit systems. We tried using it on a 64bit Windows 7 system but it failed. So I set up an environment in a VM (windows 7 64bit VS 2005 SP1 all updated) and started debugging there. The problem I come across is, I have a module (Public variables and function declarations from a driver provider FTDI). When a function from module is called the result is saved in a variable also from module. But the problem is the variable is not declared.
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Aug 24, 2009
I am looking for a good resource on variable naming conventions to illustrate variable type and where variables are declared. So I will have public variables, Private variables, private or local variables. I also may want to declare variables with the same name in different class code (i.e. in the code behind different forms). I am assuming good coding would dicatate a prefix for declaration location.
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Apr 11, 2011
with the following code example:
T04Command04 = New SqlCeCommand("Update GameResults Set CN01=@T04Var02 Where Counter=@T04Var03", T04Database01)
T04Command04.Parameters.AddWithValue("@T04Var02", T04N01)
T04Command03.Parameters.Add("@T04Var03", T04ClnRec01)
T04Command04.ExecuteNonQuery()
I am trying to use two different variables in this SqlCeCommand series, to (1) update only a particular record in the database (2) with a particular variable value. However, I get the following error:
"An SqlCeParameter with ParameterName 't04var03' is not contained by this SqlCeParameterCollection."
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May 18, 2012
Dim gg = From gs In AllData_TableList Order By gs.Biology Descending, gs.ChemistryDescending, gs.English Descending, gs.Frensh DescendingAll I need is to make this Statement order Dynamically like this
Dim Variable1 as string=Biology
Dim Variable2 as string=Chemistry
Dim Variable3 as string=English
[code].....
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Nov 23, 2009
I have a listbox that is dynamically filled by certain values depending on what table has been selected from another list box. Once a value is selected, it is being graphed vs a date & time range. With my ignorance of linq: depending on what value is selected, the linq to sql statement I need to create to grab data from my database is different as I can't use an index on an anonymous type.
result = From t In db.APS _
Where t.DateTime >= startDate And _
t.DateTime <= finishDate And t.Weight = weight _
Select t.DateTime, t.TotalConcentration
t.TotalConcentration should be selected if my listbox value is "Total Concentration", but if it's something else, like "Temperature" or "Flow Rate" (connected to appropreate database columns) - this method obviously isn't going to work. I need to be able to dynamically select a specific column from the anonymous type list, or use some other method I'm unaware of to do this.
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Nov 18, 2009
While measuring the select case performance I encounter a strange behavior of Select Case statement with the constant expression. I don't understand why its behavior is dependent on the values to be compared.
[Code]...
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Jan 10, 2011
Say that i have the following code that parse about 20k records from the DB.
Code #1
vb.net While reader.Read()
list.Add(If(Integer.TryParse(reader(0).ToString, 0), Integer.Parse(reader(0).ToString), 0))
End While
And then another code which does the very same thing but it seems to be a little cleaner.
Code #2
vb.net While reader.Read()
Dim storeowner As Integer = 0
Integer.TryParse(reader(0).ToString, storeowner)
list.Add(storeowner)
End While
This is what i am confused about; does the compiler creates a new variable automatically when i use the if statement without strictly declared variable? What approach is better in sense of performance?
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Feb 4, 2012
My stored procedure:
[Code]...
So my idea is to have (in my VB.net project) a string that could dynamically change the stored procedure "Future"
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Nov 19, 2009
I am using an INSERT INTO ... VALUES statement in the following matter to insert data into a new row of a database:
[Code]...
How can I substitute variables for the explicit values of X and Y in this statement (for example, variables XName, XAddress supplied by user input via text box)?
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Sep 22, 2009
I have an object that I know was originally declared was an enum, but I need tothe specificnum type. I'm aware of the GetType method and it appears to work correctly, but I can't figure out how to go from there to a direct type comparison For reference types, you can use Typeof(object1) Is Class1, but this doesn't seem to work for value types.
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Feb 9, 2009
I have a "if This > That then" statement, that doesn't seem to work, as it triggers regardless that "This" is smaller than "that". Does it matter that these variables are marked as strings vs integers?
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Feb 24, 2011
The following is a screenshot of the problem: What can I do?
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Dec 11, 2011
Last year (2010) I came across a FANTASTIC command that allowed me to take a string of variables with a common delimiter and break it all back out into separate variables (possibly an array) with one statement.
[Code]...
As long as the delimiter was a unique specifiable character, this one-statement command could break it out into elements. my memory and point me in the right direction.
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Sep 27, 2010
I have code, shown below, that works all except for 1 thing: The variables being passed byRef get passed, but once modified in the else section of the "if me.invokerequired" code of RecordData, the variables are never updated in the calling function. To reiterate, the calling function does not receive the updated data that is in the variables custid and amt.When debugging, I see the data change in the else section of "if me.invokerequired", but once it returns from the callback the data is missing.[code]
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Mar 23, 2012
I define some global variables of a class as follows:
Private Class MyClass
Private var1 as Decimal
Private list1 as List(Of string)[code].....
But I found that after this form is closed, all above variables, var1, list1, list2 still exist in memory. I thought they should be collected by gc since the form is already disposed as I confirmed.
Add: I have monitored half an hour after the form is closed. But these variables are not collected by gc. I have an automatic update procedure on the form which uses above variables.Since the above variables still hold values, the automatic update procedure is always called which causes exception. (One quick fix is to check if form.isDisposed in update procedure. But I do not think this is elegeant. Besides, these variables occupy memory.)
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Jan 7, 2010
Does the memory used in declaring variables are reclaimed by the OS when these variables go out of scope?Does the memory used be released by setting thier value to nothing? if not, then how can I force the garbage collector to run or excecute at a certain/desired time..How about in Windows Forms..How can we make sure that the memory used in initializing and showing forms be released if those forms were closed?
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Mar 8, 2011
Question 1: What is the difference between "Background Worker" and "Worker Pool" as indicated within the MSDN samples provided.
Question 2: I noticed while using, AddressOf _Function_, variables cannot be passed; what would be an efficient solution to this?
Question 3: While using multithreading is it required to invoke before setting variables, or only form properties?
Question 4: While using System.Net.Sockets is it safe/efficient to use Application.DoEvents while waiting for new data; or would be using a Do While loop be fine without DoEvents since the action would be multithreaded? Note: there can be up to 2000-3000 sockets in use at a time.
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