Is it possible to recall a string or object that was stored in a previous sub? The below code gives you an idea as to what I am trying to do.
Sub StoreUserData()
Dim StorName as Object
End
Sub WriteUserFile()
'Recall StorName here
End Sub
I am just getting started with VB.NET - what I couldn't find in my book is whether a new instance of an object with the same variable-name will delete the previously stored values - or will that somehow remain in memory?This is the scenario:
I open a data file and load the contents in 'Dim var As New dataObject'what happens when I again open another file and the same line is encountered:Dim var As New dataObject'
Hope the question is clear p.s. the dataObject is a simple structure with a bunch of variables in it - nothing fancy.
I have a need for a button to take the user back to their previous page.Because of how this page is accessed, the only way to do this is with javascript using history.back()
This part works perfectly apart from the fact when a user goes to click a button on the page they have gone to back to, I get the error that Request.QueryString is not supported in this context.I'm guessing the Request object is lost when javascript is directing the user to the previous page.I cannot use Request.UrlReffer either because the the nature of the back button. (it causes a loop at times).
I have a problem with a generic list, which consists of intances of a class i created. I am just amazed, each time I add a new object to the list, it overwrites the previous entries. Here is a code sample, i just can't beleive it. I am using visual studio 2010:
Dim translations As List(Of TranslatedValue) = New List(Of TranslatedValue)
If Session("ctlTexts") Is Nothing Then
Dim reader As IDataReader = DataAccessFunctions.db.GetDataReader("SELECT [ControlID], [ControlTextEN], [ControlTextDE], [ControlTextBG] FROM [dbo].[tbLanguage]", GetConnectionString)
[code]....
In Datagridview, Set as DatagridView1.ReadOnly=True,
Dgv1.Rows.Add()
When i tried to add a Row, it is copying previous Row data to new row,and also blank the previous row, why?Like Insert Row, Why...?
I have a project that I am creating a string based on a hierarchy. Without going too much into the logic, I am sure the IF THEN logic works.I have a master control table that contains a 4 number hierarchy sequence for each row. I need to loop through the control table to know how the string should look, and start a new string if the F_ID are different. I am using a For loop to index the control table and loop through it building the string as I go, based on the sequence. I am just concerned if I am referencing the previous datarow value with the .Item Overload option in the IF THEN statements correctly, and appending the stringbuilder variable using the composite primary keys properly.
The four tables example
FTable
F_ID F_Col
1 fffffff
[code]....
My problem is when i try to call Application.Run() in a application without a form i get "Object reference not set to an instance of an object." when i run it outside VS. but if ran in debug or release mode it works just fine. i may just be forgetting to setup application right, but ive done it before in this same manor and it worked fine.
Sub main() 'this runs first.
AddHandler Application.ApplicationExit, AddressOf ExitEventHandler
dbg_f("handle added")
[CODE]...
Commented out init_timer and init_ready, and now it causes the same error for the myName line. there seems to be something wrong with class Application. btw theres seems to be something wrong with the forum code formatting.
In VS2010 I'm encountering a PInvokeStackImbalance error when I call an unmanaged C function that takes a string argument. This only happens in VS2010 (works fine in earlier versions of vs). I know the MDA is more strict in VS2010 but I can't seem to figure out what the actual problem is.
[Code]...
I am utilizing a centralized class object that needs to call another class object. The program itself will do something like the following
sFieldValue = CentralObject.ObjectHandler(1, TestFunction, "FunctionVar,FunctionVar2,FunctionVar3")
In the central object I have a function
Public
Function ObjectHandler(ByVal ObjectType
As
Integer,
[code]....
I am trying to call a SetVariable command from an other form. For example, there is a movie ( called Movie ) on Form1, and a button on Form2. The button on Form2 needs to use a command like the following:
Call Movie.SetVariable("example variable", 1)
The above variable needs to be set to the movie on Form1, but I need the button to call it to be on Form2.
may I just ask a seemingly simple question for which I can't find any solution throughout all the VB.NET documentation: I have to call a (non-static) method of another object (instance!) based upon the name of the method (given as a string).
View 1 RepliesI have a form and I am calling a method from a module in that form. However, how to do i call the object into the method, since Me doesn't work.
Example:
in the module:
Function printname()
Console.WriteLine("Form called with is titled:" + me. text)
[code]....
I have a method called ADD in a class that connects to a database. The database class name is XDB. I also have an object named XXX in it's own separate class with properties.One of the instructions for the Button named ADD click event is:
'Call Add method passing in the XXX object
So this is how I coded:
'declare a variable X as an object instance of XXX
Dim X As New XXX[code].....
I know it's wrong since it doesn't add the XXX and the form doesn't close but I don't know what I'm doing wrong.
Under component services, a COM+ component is used by the company, right-clicking it and choosing 'Activation' tab will show the 'constructor string' that is used for DB server connection by all applications. How can I access it the simplest way possible?
[Code]...
I have a class library that contains a number of classes. I would like to dynamically create an instance of one of these classes, set its properties, and call a method.
Example:
Public Interface IExample
Sub DoSomething()
End Interface
Public Class ExampleClass
[Code].....
I'm trying to setup a WCF web service to be consumed by JavaScript using JSON and jQuery.I've noticed that you can send JSON without a DataContract if the service method parameters match the naming structure of the JSON object:
<ServiceContract(Namespace:="http://foo.com/bar")>
<AspNetCompatibilityRequirements(RequirementsMode:=AspNetCompatibilityRequirementsMode.Allowed)>
[code]....
(New clsViewIllus).View(MyIBaseView, enumViewSolveTypes.View, Me, , True)
... in VB? Basically too lazy to do this:
Dim vi As New clsViewIllus
vi.View(MyIBaseView, enumViewSolveTypes.View, Me, , True)
I have some files in vb.net that have "Option Strict Off" to allow for bad programming. When I convert to c# I use "dynamic" until I come back and fix problems, and this works in all cases But now I have this code:
Public Class ContractResults
'Big class definition
Public Shared Sub CleanCache()
[code].....
And in a file with Option Strict Off:
Public Sub VerifyResults(result as Object)
'Here, result is normally ContractResults
'first it check for that then call this:
result.CleanCache()
End Sub
In c# I use "dynamic", but a runtime error pops up when I call "static" method with dynamic reference. In vb.net, I can called "shared" sub from instance, but in c# this is not allowed
Exception:
"Microsoft.CSharp.RuntimeBinder.RuntimeBinderException"
"Member 'ContractTypes.ContractResults.CleanCache()' cannot be accessed with an instance reference; qualify it with a type name instead"
It seems I must convert code to use actual type, but then this means much rewriting of more parts. Is anyone able to show another way?I want to make sure you do not think I can use (result as ContractResults).CleanCache();Because all types that may be passed in have "CleanCache()" method, but do not inherits from anything the same other than "Object". There are many types (30!) that have this "static" method and so that is why it uses Option Strict Off?
Dim db As New DataClasses2DataContext
Dim newvet = From n In db.vets Select n.vetid Distinct
(Label1.Text = newvet.Count.ToString)
this is the error message I am getting:Object reference not set to an instance of an object.
dim myCollection as new Specialized.StringCollection
dim myFoundThings as new ArrayList
dim index as Integer
dim newResultMemberName as String
[code]....
This is part of some code that will run without user interaction once it's spinning away, and I need to create a unique object from some items found in a StringCollection, naming the objects using information found in the strings stored in that StringCollection.
How can I raise an event from another class which implements an interface that contains an event?
Public Interface IMyEvent
Event MyEvent()
End Interface
[Code].....
Note the comment - that code doesn't work. How can I raise an event like this, if it's contained within another class through an interface?
So I'm trying to write a MasterMind game, but I have a problem I have 40 pictureboxes set up in 10 different rows, and I want to have one code handle all 10 rows, rather than copying and pasting the code and changing the names of the pictureboxes. I've been trying to use a variable to achieve this, but if it's possible, then I don't know the correct way to do it.This is what I have right now:
[Code]...
I am using following code for browser helper object. But when I try to run this BHO in internet explorer SetSite method is not called.
using System;
using System.Collections.Generic;
using System.Text;
using SHDocVw;
using mshtml;
using System.IO;
using Microsoft.Win32;
[Code] .....
I have a webpage that contains an ActiveX object, called object1, and a javascript function, called alertMe(input). I wish that if user clicks on different location on object1, it will call the javascript function. Is it possible to do this? If it's possible, how should I write the calling in the ActiveX object?
View 1 RepliesI have written my own function, which in C would be declared like this, using standard Win32 calling conventions:int Thing( char * command, char * buffer, int * BufSize);I have the following amount of VB figured out, which should import the dll and call this function, wrapping it up to make it easy to call Thing("CommandHere",GetDataBackHere).UPDATE:This code is now a working solution, as shown here:
Imports Microsoft.VisualBasic
Imports System.Runtime.InteropServices
Imports System
Imports System.Text
[Code]...
Updates: I got the code to build by following the help received here, and then I had forgot the As Return Type (which got me a MarshalDirectiveException PInvokeRestriction). Then I had an assertion failure inside my DLL, which lead to an SEHException. Once fixed, this works BEAUTIFULLY. There are newsgroups where people are saying this can not be done, that VB only loads managed dll assemblies (which I guess is the normal thing most VB users are used to).
Trying to replace Cells(RowIndex,ColumnIndex).Value() calls by row-wise references for performance, I permanently fail at referencing the result. Starting with Excel Interop - Efficiency and performance, which contains the tip to use get_range, i.e.
//get values
object[,] objectArray = shtName.get_Range("A1:Z100").Value2;
iFace = Convert.ToInt32(objectArray[1,1]);
//set values
object[,] objectArray = new object[3,1] {{"A"}{"B"}{"C"}};
rngName.Value2 = objectArray;
[Code]...
However, referencing Values with two dimension indices always returns an "index was outside the bounds of the array" exception. Inspecting the array with the debugger shows a nice 2-dimensional array which should has 17 elements on the second dimension, so Value (0,0) should indeed be a valid reference -- but it isn't:
The debugger lets me inspect Value, I can also drill down to Value(0,0) and see the correct value, but re-evaluating just that element, i.e. inspecting "Value (0,0)" returns above message.
This is something that has been bugging me for a while as it is easily fixed but not desirable.I have a DataGridView that has 5 columns. The first is called ID.In vb.net the following line gives an error "Object reference not set to an instance of an object": dgvJobs.Columns("ID").Visible = False ' ERROR dgvJobs.Columns(0).Visible = False ' OK
Obviously using the name is much better than a hard coded value to reference the column but wondering if there is anything i can do to get this to work correctly?The datagridview datasource is BindingSource control with the datasource being a dataset.
[Code]...
MVC 3 razor VB.NET project. I have resorted to manual building a list for a drop down box so I can insure certain values are available in the select list and also to control what the first item is in the list. The below is my code snippet for the part that is giving me problems..
[Code]...
I have database with class names listed in string field. I want to circle thru records and call certain class.
Eg.
Data table
ID ClassName
1 ClsCreateButton
2 ClsCreatePanel
After retriving this data in dataset(ds.tblClass) I want to do next:
Dim aClass as New ds.tblClass("ClassName")
Do something with aClass...
Is it possible to call a sub with a string.vb Dim subname as stringsubname = textbox1.text(Code for calling sub, subname)
View 5 Replies