Forms :: Create A Dynamic DataGridView From A List Of Objects?
Feb 6, 2009
I am relatively new to C# and winforms, although I have been using Java for years, so forgive me if im asking something relatively straightforward!I have a DataGridView, it needs to update regularly so I wish to provide a Collection of objects as its DataSource and NOT a database table.So far I have a List<MyObject> which will be constantly updated via a BackgroundWorker thread. I want my DataGridView to update when a change has been made to the List i.e. if the objects are resorted, added to or deleted from etc.Currently my DataGridView only displays the first object I add to the List, if I add more the DataGridView doesn't update to display the new objects added.This is a basic overview of how im coding it:
private List<MyObject> myList= new List<MyObject>();
myDataGridView.DataSource = myList;
Then my BackgroundWorker thread updates the list, e.g.
I have to ask my first question at some point, so here she goes.I am trying to create a dynamic list of objects. The objects will have several types (String, Integer) associated with them. Currently I am forming a Collection as I instantiate new objects.Is there a prefered to map this collection to, say, a Datagridview? Will I have to Iterate through the collection and add the rows at each iteration?Would I be better served using an ArrayList or something else over a Collection?
If I have a large number of classes, each similar to the other in certain aspects (they all share a common base class, but each does things differently), and I need to create Windows forms for each to allow easy changing of their values through a GUI? Create one matching form for each object in VS' forms designer, Or Use code to create the forms dynamically at runtime.
#2 makes the most sense to me, because a lot of these objects will share very common features of the form, notably "Ok" and "Cancel" buttons. But one object might need to draw a textbox on the form while another might need to draw a combobox. Not to mention, if I want to put icons on the "Ok" and "Cancel" buttons, I'd have to do this for each copy of the form in designer, and that sounds like it could get out of hand quickly.But is drawing forms through code sane? VS' forms designer is pretty sophisticated and designed to make life easier. Am I wise to consider ignoring its functionality and diving into the trench warfare of forms design through code? Or are there examples of automating form creation based on an existing object's properties?
I am trying to create a form where depending on what the user selects, they are shown a collection of images from the web. Depending on what they select there will be a different amount of images so each picture will need to be added dynamically.
I am able to create PictureBoxes dynamically however I'm stumped how to create event handling in order for each control to give a unique response.This is what I originally tried but I got an error..
Private Sub Form1_Load For i=0 To 10 Dim picBox As PictureBox
[code]....
The error I got was
'AddressOf' operand must be the name of a method (without parentheses)
How ridiculous that you can't include arguments in your AddressOf! Can anyone shed some light on my situation (or knows a better way of carrying out my goal)?
I would like to create list of child objects from list of parent object. Like If i have list of bookingroom which has one member room then i would like to create list of room from it.
eg. code:
Dim BookingRoomList As List(Of BookingRoom) = New List(Of BookingRoom) Dim RoomList As List(Of Room) = New List(Of Room) BookingRoomList = BookingRooms.FillGrid()
[Code]....
Is there any short cut method instead of iterating over for earch?
I need two seperate lists, which every item is Integer, String, Bitmap - and one which every item is Integer, String String. However I don't know how to do this, or even where to look - I've googled for custom objects and custom object lists. What I'm trying to do is this.Custom Object1 is Integer, String, Bitmap Custom Object2 is Integer, String, String
In one thread I'll be adding items to List1(Of Object1), and processing them, and adding the results to List2(Of Object2), however I need to be able from other threads to look at the list and say only give me the items where Integer = (my thread ID), is this possible? Any help, or even links to information that would be relevant to this request would be helpful?
I figure I should use 'Aggregate' but apparently I am getting it wrong First I get a list of my Entity objects Dim employers As List(Of myEntity) = (New XXXX()).getZZZ(userName, userType) Then I figured this would be a way to put all the names in a string Dim names as String = employers.Aggregate(Function(current, [next]) current.Name & " " & [next].Name)
I have pairs of controls: immagebox + textbox = one pair.I want these to show up in a single column grid/tabular format.Each cell contains one image/text pair.I want this grid to scroll because the number of pairs is dynamic depending on a user selection.I suppose I will be adding these controls in code at runtime when the user makes his/her selection.
I have been playing with VB6 for quite a few years now and I can normally get by ok on my own.I finally made the move to VB.net, but I am totally lost.I have started writing a program that is basically a planner. It helps the user organize and plan activities with a client.I have created the ui and have added a BindingNavigator and it happily pulls in the records from my Access database which I can cycle through.What I would like it to be able to do is, allow the user to see all the current records (maybe in a flexgrid), select which record he/she would like to view, then the entire record is populated into the ui.I would have no problem in vb6 of course...but I could do with a little help in vb.net (2008).My main problem is I think is, once the flexgrid is populated, how to create the event that allows the user to view and update that record once in the ui.
I finally made the move to VB.net, but I am totally lost.I have started writing a program that is basically a planner. It helps the user organize and plan activities with a client.
I have created the ui and have added a BindingNavigator and it happily pulls in the records from my Access database which I can cycle through.What I would like it to be able to do is, allow the user to see all the current records (maybe in a flexgrid), select which record he/she would like to view, then the entire record is populated into the ui.
I would have no problem in vb6 of course...but I could do with a little help in vb.net (2008).My main problem is I think is, once the flexgrid is populated, how to create the event that allows the user to view and update that record once in the ui.
how to create a list shown in following image using vb 2005 ?i want the following list (contents doesn't matters) to be appeared when i click the button.
What I am trying to do is to instantly apply a filter to a large list of data such that the list is updated almost immediately regardless of the number of items in the list. I have this working using a listview right now but it is far from instant, a list of 5000 items takes over a minute to get through. What I do currently is to maintain a cache of my data that my listview entries are based on. When the user selects a filter I parse this data one item at a time and determine if each item should still be displayed in the listview, if not I remove it. The complexity of determining whether or not a data entry meets the filter requirements is O(1), but just getting through each element in a loop takes significant time, and so does updating the list view graphically at the end of the process.
I have considered using a datagridview instead, using a database connection. I have never done this before and my main question here is whether this would allow me to do what I have described. With the database I could form an SQL query to return only the items that meet the new filter requirements... but would the data in the form update immediately, or would there still be significant delay?
I have BIG trouble trying to understand the decleration and creation of an instance with respect to arrays of objects. Basically I struggle with with this error:
Object reference not set to an instance of an object.
complete the test code I made below, so that I can try to understand it..? Been figthing with this for hours..
I made a browser and its awesome but i want to reference the browser name so that i can add script to it, I am calling the new browser window "wb" cause that's what it gets named in the script. here is my code. (it labels the tab, the window, and changes the URL text field)
Private Sub wb_Navigated(ByVal sender As Object, ByVal e As System.Windows.Forms.WebBrowserNavigatedEventArgs) Handles wb.Navigated TextBox1.Text = wb.Url.ToString() Me.Text = CType(TabControl1.SelectedTab.Controls.Item(0), WebBrowser).DocumentTitle & " - My Browser"
[code]....
It says "Browse.Name = "wb"" so thats why im trying to call it "wb". I inserted a WebBrowser on the form named wb and then tried to run it and it worked, it labeled the window, tab, and changed the URL field. So i know that the script works. Please help me, I know you guys can solve this, I'm really new at this.So my final question is... What should I call the browser instead of "wb" when I am referring to it in the first script I posted above? I am so confused. How do you refer to an object that gets created dynamically?
I am using a DataGridView bound to a BindingSource which is itself bound to a List of objects. This all works well until I remove objects from the list. If I am scrolled down to the bottom of the DataGridView and then remove a bunch of items from the list it is bound to it generates a DataError exception because the length changed and the rows I am looking at no longer exist... I changed my code to handle that error, but now instead of popping up a message it SLOWLY erases the data in each of the newly invalid rows at the end of the table (I think each time it does one it generates a new DataError, which is why it is so slow).
How do I prevent this? I want to be able to dynamically (and programmatically) add and remove items from the table without the possibility of this error... I assumed this would be handled automatically as part of the data binding process but I guess not.
'decleare variables Dim vmcount As Integer Dim tabcount As Integer[code].....
The trouble I'm having is working out a way to be able to call the objects in the dynamically created usercontrols. I thought a list maybe an option but I am struggling to get the syntax/get it working. Wondering if anyone has some ideas or different approaches..
Limited to using v2.0 of .Net framework (we use VB.net) due to environmental constraints on our servers.I've got an ASP.net webpage which pulls data from a webservice that performs checks on user accounts in active directory. Operators can check multiple accounts at one time using the web interface. The webservice returns a list(of AccountCheck) objects which themselves contain single properties like username, email address, and List(of AccountError) objects which contain multiple properties.[code]What I want to do is using some kind of repeater, create multiple panels or divs which contain labels showing the username, email etc, and a gridview which has the accounterror list bound to it to show all the errors. The users could be checking 2, 5, 7 accounts at once, and is dynamic.
I have an Object structured as follows:[code]I thought this would work but I keep getting the following error: Object reference not set to an instance of an object.
just needed to get my head round something. Say I have a class 'myClass' with properties ID and Name. Now say I have 2 lists of objects of this type as follows:
Dim list1 as List(of myClass) = GetList1() Dim list2 as List(of myClass) = GetList2()
What I want is to 'intersect' (this may not be the right word!) the two sets of data by the Name property, but bring back the ID property from list1. A suitable database analogy would be if list1 and list2 were tables, I'd want to do a left join from list1 to list2 on the Name field.
The scenario is this, I have several variables that are set as a list(of objects). The values for these lists are populated during code via a SQL query. I want to be able to take these values and then use them within another SQL query. Each time the program runs the values will be different and there will be more or less within the list.
