i made a class which has speed,symbol (string "*") and location what is the acceptable way to actually display the class symbol property on the screen ?the class will be stored in a list<OF T> and will contains hundreds dynamically instances
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I am trying to display my data in datagridview. I created a class with different property and used its list as the datasource. it worked fine. but I got confused how to do that in case we have nested class.My Classes are as follows:
class Category
property UIN as integer
property Name as string
[code].....
I have 2 tables Table A & Table B Table A has the table values that I want to be populated in a datagridview control.The challenge is that column 1 in table A contains an ID(foreign key) to a name field that is a located in table B. I need the datagrid to have the first column be a combobox that displays the names(from Table B) that are already in table A via the ID's, but reference the populating values from Table B. So that when you bring down the combobox you would be choosing from Table B data but populating table A with the ID and you would see a name there instead of an ID.[code] How do I populate my DS dataset with Table B? And how can I create a link to these two tables using a bound datagridview control?
View 1 RepliesI know I have done this before and as I remember it should be really easy. But for some strange reason I can't do it now and I am about to jump off the building.I will make it simple:Two tables, one is just a list of products and their code.The other table: "details" has a field named product. I want to store only the code there.In the second table's entry form, I am putting a combobox. This combo box should display the list of products, their names, but depending on which one is selected, the code is what is passed to the table "details". Currently If I set the display member to product and the value member to code it still pases the product to the binded data source.
View 3 RepliesI have a database that holds information about a particular job. One of those things is a customerID. CustomerID links to another table containing customer details. I have a combo box attached to a custom object that holds customerID as the valuemember and CustomerName as the displaymember.The JobDetails holds the customerID info. How do I set the default selection in the combobox based on the ValueMember of the combo box?
View 2 RepliesI am trying to add a splash screen to my app but I get an few errors "Application is not a member of my" .Not sure if it has to do with the fact that under project properties the windows application framework is disabled and I cannot figure out how to enable it.
View 2 Replieshow do I overcome it? I have created a class and compiled into .dll This code
[Code]...
In Visual Studio 2008, if I do this:
[Code]....
Does anyone here know how to get the above to work WITHOUT warnings being generated?
In the following code i get a warning at line 59:Warning 1: Access of shared member, constant member, enum member or nested type through an instance; qualifying expression will not be evaluated.and.. At line 78 I get this Warning:
Warning 2 Property 'SelectedCustomer' doesn't return a value on all code paths. A null reference exception could occur at run time when the result is used.
The program compiles and runs well, but i cant' undesrtand the reason for these warnings. Any Idea ?
1: Public Class Form1
2:
3: 'Form level members
4: Private objCustomers As New ArrayList
[code]....
I have been battling with this problem for months with virtually no success. I am using Visual Studio 2008 Professional. The database is Microsoft SQL 2005.
I have two combo boxes - both bound to database tables. These are: Combo box 1 is for "VAT" and is bound to the VAT table. This table has 3 columns configured as shown below:
[Code]....
The commented out code was my pathetic attempt to put the Value member of one combo box into the display of the other. This obviously does not work and my web browser, when using Google, is full of purple headers showing the sites that I have visited looking for an answer.
When I have this working, I want to use the feature in a datagridview which may make a difference to how the problem is approached.
Cannot appear to be able to get this function to not have the above error.Private Function GetIncidentActions(ByVal FromAgentID As Integer, ByVal ToAgentID As Integer, ByVal incidentAction As Integer, ByVal ActionDate As Date) As String
[Code]...
Im trying to make a custom splash screen , but i cant seem to get it to work. Im trying to display a welcome screen for 3 seconds then close and display form1 (main form).Heres my current code.
[Code]...
I've encountered a problem which challenges my understanding of access modifiers in VB.Net. I have a class declared Friend. If I declare its properties Public, the application works. If I declare them Friend, the application fails.
Before this, I believed that, in a class declared Friend, it would make no functional difference whether I declared the members Public or Friend. I thought class access declarations applied their restrictions to all nested entities, so nested properties declared Public were effectively restricted as if they had been declared Friend. Obviously, I was wrong. Can anyone explain how access modifiers really work, or point me to the relevant documentation?
Here is a more detailed description of the situation: I have a Friend class called StripTask with properties called StripDate, HistorianDate, and TaskText. I have a collection of StripTasks (called _StripTasks) which is used as the data source for a Syncfusion GridDataBoundGrid. The way the binding works, I need to pass the name of a StripTask property to each of the grid columns so each column knows what data to display. It ends up looking something like this:_DataBoundGrid.GridBoundColumns(1).MappingName = "StripDate". When the mapped properties are declared Public, it works. When the mapped properties are declared Friend, the grid is populated with the correct number of rows, but every cell is empty.
As a follow-up question, is it a good idea to avoid things, such as this Syncfusion binding method, which require me to pass property names as strings? It just feels as if I'm inviting trouble.
I realize that this is a very basic question, but it's been a long time since I've played with VB. Why can't I call the Synch() Sub/Function in my CMMS_SCAD_CLASS class from my Main module? I get the following compile-time error:
'Synch' is not a member of 'ConsoleApplication1.CMMS_SCADA_CLASS.'
Main class:
HTML
Module Main
Sub Main()
Dim meterClass As New CMMS_SCADA_CLASS()
[Code]....
I have an app which hangs in production periodically more frequently on some PC's than others. While trying to resolve this I have started to analyse the application using WIndows native debuggers, such as ntsd,which appear to throw up a large number of clr exceptions (first chance). While alot of these are handled in my code some appear to be related to issues with Windows binding. For example the exception' Cannot bind to the new display member' appear to occur when I assign a BO to the datasource of a bindingSource control while if I directly set the datasource of a UI control, which would have referred to the bindingSource, the message disappears.In all cases I would have the displaymember and valuemember set for my list controls before updating the bindingsource control's datasource.
View 2 RepliesI've set my DisplayMember property of the listbox to the property I want yet when I add the objects to my listbox it "fails" and instead uses the .ToString of the entire object which doesn't return what I want.
[URL]
the DisplayMember only works if your listbox has a datasource. Well I'm not using a DataSource, like that guy I'm just using .Add. So how do I get DisplayMember to work without using a DataSource?Also I tried putting all of the objects (their simple item structures) into a List Of and then set that list as the DataSource to the ListBox and it actually added all of the objects to the listbox however the DisplayMember still didn't work and all I got where the results of Object.ToString().
I have a small problem. DataGridViewComboBoxColumn display value from ValueMember and not from DisplayMember. The grid work fine and when I select somthing from this column I see DisplayMember value but when focus lost the grid show ValueMember. I have this code combo box column:
statusCBoxColumn.DataSource = dt 'datatable with two fields StatusId and StatusText
statusCBoxColumn.DisplayMember = "StatusText" 'is type NVarchar
statusCBoxColumn.ValueMember = "StatusId" 'is type Int
[Code]....
I have been battling with this problem for months with virtually no success.
I am using Visual Studio 2008 Professional. The database is Microsoft SQL 2005.
I have an unbound datagridview with two combo boxes � both bound to database tables. These are:
Combo box 1 is for VAT and is bound to the VAT table. This table has 3 columns configured as shown below[code]...
We have a coding standard that says all shared (static) fields and methods must be called with the class name. E.g. NameOfClass.whatever Is there a tool that we can use to check this is in fact the case? (Likewise for modules) I should have make it clearer we are using VB.NET.
[Code]...
I have a custom class called "Time" with the following function, for determining if one Time equals another Time.
Public Shared Shadows Function Equals(ByVal Time1 As Time, ByVal Time2 As Time) As Boolean
Dim x(2) As Integer
x(0) = CInt(Time1.Hour)
x(1) = CInt(Time1.Minute)
[code].....
Access of shared member, constant member, enum member or nested type through an instance; qualifying expression will not be evaluated.I know it shouldn't do any harm, just let the compiler skip evaluation, but is it a way of getting rid of this warning?
How should class member variables be used in combination with class methods?Let's say I have a class 'C' with a member variable 'someData'.I call C.getData(), which does not return a value but instead puts data in C.someData. The class that instantiated 'C' first calls C.getData and then uses the data by accessing the member variable C.someData.I call C.getData() in the class that instantiated 'C' which is a function that returns data.I myself prefer the second way. But it also depends on the situation and it's a small difference. Is it 'bad' to have class methods that depend on the classes internal state? What are the best conventions?
View 2 RepliesWhats the difference between these two initialization methods for obj? I've seen both of these, but know know if there is an appropriate time to use one vs the other. I found this post which covers C#, but not sure if the same applies to VB.Net.[code]
View 3 RepliesI have a routine that accepts a List of Objects, a property name and a value to search for and simply returns whether or not it found it.The code I have hangs up at the For loop in the findit routine.[code]
View 4 RepliesIf I have the following structure:[code]How can I select it in a conditional like this? [code]I know that myUsers.Contains(.ID = "1") is totally wrong, but I am curious how to do something like that?Is it possible? Is this a job for LINQ?
View 3 RepliesI want to replace the Public Declarations that I currently store in a Module with a Class.Currently in my Module I have a declaration like this:
Public SetPath As String = My.Computer.FileSystem.SpecialDirectories.MyDocuments
How do I get the same functionality from a Class?
Public Class Audits
Private _SetPath As String
Public Property SetPath() As String
[code]....
I know I can reference the SetPath in code by doing a Dim aud as New Audit so my question is this. Where is the correct place to put the
= My.Computer.FileSystem.SpecialDirectories.MyDocuments
And is this an good example of a member that should be shared? If so does both the Private and the Public need to be shared. I just started using Refactor Pro and it almost always is recommending that I make all members shared. Is there ever a good reason not to do so?
I have a bunch of classes that all contain a Shared ReadOnly Dictionary. If I want to access that Dictionary when the class is a generic type (such as when I have a wrapper function that takes T as an interface that all of these classes implement), what's the way to do it?
I want to do something like GetType(T).GetMember("Dict"), but that will return a MemberInfo type, and that cannot be cast to a Dictionary of my defined type(s). For calling functions this way, one can use a delegate + CreateDelegate + GetMethod. But there doesn't seem to be an equivalent Create*for GetMember stuff. Or am I missing something?
If I plug the GetMember call into the immediate window, and then use a subscript as if it is an array, then the debug output says I am getting a Dictionary back. But if I use that same approach in the actual function that I am trying to write, then I get an error about System.Reflection.MemberInfo cannot be converted to Dictionary(X, Y)
I need to avoid serializing an Event class member because when the event is handled by an object that is not marked as Serializable the serialization will fail.
I tried using the NonSerialized attribute on the Event class member but it fails to compile. This line of code:<NonSerialized()> Public Event PropertyValueChanged()
produces the following error: Attribute 'NonSerializedAttribute' cannot be applied to
'PropertyValueChanged' because the
attribute is not valid on this
declaration type.
Public Event PropertyValueChanged() ' compiles but needs the extra handling described below
Is there another way to avoid serializing Event members? This is not a problem if the event is not handled and I can work around it by cloning the objects (and ignoring the event) before serializing them. Just wondering if there is a better way.
I know that the MenuItem class contains an internal class named MenuItemData, which contains itself an internal member named onDrawItem. Given a MenuItem, I want to retrieve the object corresponding to the member onDrawItem. But all I manage to do is to get the FieldInfo, not the object itself.
Here is my code:
Dim obj As Object
Dim fi As FieldInfo
Dim item as System.Windows.Forms.MenuItem
Dim mType As System.Type
[Code] .....
When reaching the last line, I get an error saying something like that (it's traduced):
The field 'onDrawItem' défined in type 'System.Windows.Forms.MenuItem+MenuItemData' is not a field of the target object of type 'System.Windows.Forms.MenuItem. I don't know what object to pass to the GetValue function on the last line. My goal is to remove the base eventHandler of the menuItem, named DrawItem. See this post and the function RemoveClickEventin the accepted answer for a better understanding.
I am attempting to fix a vb.net (using Visual Studio 2005) and while I have extensive experience using VB6, my vb.net skills are pretty much as a beginner.I've added some code to this program which calls a stored procedure but it won't run becauseof an error when it compiles:
Error 1 'usp_select_media_to_removeNoGenres' is not a member of 'Lynd.Data.TestDatabase._StoredProceduresClass'
[code]....
I would like to understand the Pro & Cons in using the commonly used methods via Singleton class against Shared (Static) members of a class in VB.Net. It could be in terms Time, Space complexity or best practices. I have a BankAccount class with methods doing some business logic.
GetBalance()
GetLast5Credits()
GetMiniStatement()
[code].....
