Bind A CollectionContainer To A Collection In A View Model?
Jun 22, 2011
I have a view model with a property that exposes a collection of things.I have a ComboBox whose ItemsSource property is bound to this collection.Now the user can select from the list.I want to allow the user to clear the selection, so I want to add an item (that is Null) to ComboBox. It's pretty straightforward.
I decided to try and use a CompositeCollection for the ItemsSource so that I could add the items in the existing list to the ComboBox as well as the extra Null item.After fighting with this for a while I decided to return to the documentation on the CompositeCollection Class. I copied their example and the modified it to use a view model instead of Static Resources.
I discovered that no items show up in the list when I bind the CollectionContainer to the list exposed by the ViewModel.I'm not sure how to get around this problem and I'm looking for any advice on this topic.
I am new to .net, I am just taking a shot in the dark through this whole thing. I have an Addresses table with a StateID and CountryID field. They refer to the States and Countries table. I am using LINQ to SQL and Visual Studio 2010.
I am wondering what I am missing in the attached code that is making it impossible for me to make the VB.NET program below work using MVC (Model-View-Controller). Right now, I am really lost despite my best efforts...
I am trying to implement the observer pattern and think that my code is getting closer to MVC but not quite there yet, firstly because it wont even run ... nevertheless I know that there is someone out there who knows what I am doing wrong and I would definitely benefit from any guidance or help that someone more experienced in MVC VB.NET implementation can give .. hence this letter.
I have an MVC application where all the data is tied together by VisitDate table in my database. The home page is a strongly typed view of type VisitDate, all it does is pull up some simple data. Now, here's where I'm having a problem. I need a link that passes the current model in the view back to a separate controller action so I can render a different page with different data. Here are my two controller actions. I'm going from News.aspx to FrontPage.aspx and hopefully passing SchoolVisit. [Code]
I will be doing an MVVM Project soon and I'm working a couple tutorial/examples out. How do I take the following code and connect it to a database. If I were to have a datagrid, how can I change information in the datagrid and have it automatically update? I'll be using MS SQL.
While working with an excel file (.xlsx), the data I get from it is an IEnumerable(of Dictionary). When I bind this to my datagrid, I get the problem that I only see 2 columnsI've been tracing this problem and discovered that in the first row in the excel, there are only 2 values (cell C and D). I think the binding to datagrid looks at this first row to create its headers. This results in my datagrid only showing columns C and D.
I want to bind data to telerik list view, if the database four record,each page of list view show 3 record, that means it will have an record show on 2nd page then still got 2 record was empty, so i want to show the first, two record under the fourth record,
i am trying to bind the combo box through details view in vb.net but unable. i am making a login form and i want to display two values e.g usertype admin , employee in combobox but when i run the form it doesnot show me anything in combo box although i have selected the true binding source and display member but still unable. Another problem is in my form load event if i left this line written
Me.StaffTableAdapter.Fill(Me.StaffDataSet.staff)
it not only shows me the combo box values but also types in the user name and password which is saved in database. All i wana do is when the form gets loaded ..user name and password field should be bland but the user type field should show two values.
I am having some problem in binding my linq with my data grid view..The code for binding is as follows:
objdt = objdalProduct.SelectProduct() It brings all the data from the database Dim Query = From Product In objdt.AsEnumerable _ Where Product.Field(Of String)("ProductName") = cbProductName.Text _ Select New With _
I want to bind two dynamic column's check box in one grid view like category column have some types and sub category have some types.. I should bind that two fields dynamic check box's with in a one grid view..how to do it.
I managed to do ASP.NET authentication work wih AD. Now, I want to query an OU in AD and display the result either ListView or GridView in ASP.NET page.[code]In the organizational unit (OU) UsersStudents there are following columns:First Name, Last Name, Pre-Windows 2000 Logon Name, Name , Type. I want to query column First Name, Last Name, Pre-Windows 2000 Logon Name in OU UsersStudents and bind the result to ListView or GridView.
I have a form called studentForm which has a studentCombobox, studentTextbox and a studentDatagridView
In the constructor of the studentForm I need to bind studentCombobox to the StudentbindingSource of the main form and to bind studentDataGridView to appropriate binding source in the mainForm.So that this datagrid view displays all the bookings for the studentID currently selected in studentComboBox
I am trying to bind my SQL param's qurey to bind to a table. My problem is i get this error "Fill: SelectCommand.Connection property has not been initialized."
Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click If RadioButton3.Checked = True Then Dim connectionGrid As SqlConnection = New SqlConnection("Data Source=BST;Initial Catalog=dsfs;uid=dfsdf; pwd='dsfsf'") Dim commandgrid As SqlCommand = New SqlCommand()
Is it good practice to store sub-collections of item X inside a parent collection of item X for caching 'filter-queries' which are performed on the parent collection? (They won't be used together (as in color AND type).) Or is it also ok to just Loop over the collection and return the correct entities in a temporary collection?
I have been researching for a couple of days now and to no avail. Does Anyone know how to make a custom collection that take advantage of the collection editor? I would like to be able to have 3 Color Values, 1 Boolean and 1 String.
I'm currently developing an application with a reasonably complex DataGridView that allows the user to build the lines of a sales document: Quantitiy, Description, Price, etc with some additional fields to help calculate price based on cost or discount i'm sure you get the jist - all this means we're not just diplaying data but adding and manipulating it - It also means there's mainly decimal fields, nit just simple text fields
Now, i'm new to VB.net, so i've perhaps done things a bit backwards during my learning curve, namely designing and coding my DGV before creating the underlying database table and binding to it - so as i'm sure you can image there's a bit recoding to do to allow for the fact that it's now bound to a datasource.
I'd got the DGV working just how a wanted it to, but now that i've bound it to a datasource i'm hiting multiple problems with: Formating the appearance of figures in the DGV Problems with blank fields while enering data (before the i try to save the data back to the database) How the DGV is functioning - it seems to behave differently when adding lines to a new sales document than it does when adding lines to an existing sales document
And given that when saving edits to an existing line i need to provide a valid update command i'm begining to think that it might be easier to scrap the databinding altogether and just Select, Add and Edit the database with code rather than binding the DGV in the IDE
I've read various threads about avoiding databinding due to it's limitations, but i've also read that it's far better in later versions of Visual Studio and .net. and i'm using VS2010
I'd just like some advise as to whether my gut feeling is right or whether i should persevere with databinding the DGV. i've noticed some quirks of databinding while working with other controls such as text and combo boxes, but i've overcome these and the result seems to be easier than coding the data transfer manually.
But i'm really struggling with databinding the DGV and the fact that i'm dtatbinding to a seperate table to the rest of the controls is leaning me away from databinding
I'm trying to support Basic.NET on my framework so I'm trying to convert C# 4 code to Basic.NET 10. Microsoft is committed to "co-evolve" these two but I'm having a problem with collection initialization... I found that I can initialize a collection much like in C#:
I've got the following ADO.NET Entity Framework Entity Data Model:I want to find all the Policyholders with both a Service of a given Id and also a Keyword of a given Status.
This LINQ Does Not Work:
Dim ServicesId As Integer = ... Dim KeywordStatus As Integer = ... Dim FoundPolicyholders = From p As Policyholder In db.PolicyholderSet.Include("Keywords").Include("Services") _ Where p.Services.Id = ServicesId _ And p.Keywords.Status = KeywordStatus _ Select p
The Where clause cannot search the p.Services and p.Keywords EntityCollections in that way.
currently in my application I have a Global Collection that is a Collection of Collections.Currently I am trying to add items/ elements to one of the child collections of the Global Collection but I am unable to use the collections methods of the child.When I assign a variable to the child collection and return the collection it is just an object with the collection inside.
Ex: Dim GlobalCollection as New Collection Dim ChildCollection1 as New Collection Dim tempCurrentCollection[code]......
I've been working with a CMS called InsiteCreations 2008. I'm running into an error I just can't wrap my head around. I would even be willing to compensate anyone a small amount over paypal, for a solution. The error is rare in occurance, and appears when clicking about 3-4% of links to other pages within our CMS.The full code page is quite large, but there seems to be only one function associated with the error. The error also only appears when not logged into the CMS. If logged into the CMS, clicking the link simply displays the page as normal. I have already checked permissions on the page from the CMS admin console, and it is public.
The error message is as follows:
Server Error in '/' Application.Collection index must be in the range 1 to the size of the collection. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Public Class Store Public Overridable Property Areas As List(Of Area) End Class Public Class Area
[code]....
What's the quickest way to get a total count of shelves for a store? I.e. for a store I get the total count of areas by using Areas.Count Or will I need to loop through each area and tally the count of shelves?
I have an ASP.NET app with lots of textboxes all over the page that need updating at various points through program execution. These textboxes actually belong to a certain class, so for easy updating I thought I could create a Dictionary(Of string, object) and add the control.ID and the control to it and then for updating do something like this:
I need to convert a VB Collection to a modern one, like Dictionary or Hashtable. For my approach, I need the Collection's KEYS. Googling tells me that it's impossible. Re-writing the entire application using new collections is not an option as the application is really old and large (converted from VB6 to VB.Net).Using the old Collection also is not good - as there are new components in development.Converting a - for example - Hashtable to Collection works:
using VBCollection = Microsoft.VisualBasic.Collection; public static VBCollection ToVBCollection(this Hashtable table) {
Assuming an architecture as such.MODEL > BLL > DLL
Trying to implement lazy loading in my MODEL I have run into a circular dependency between my MODEL and BLL..Basically imagine a property in my model that I want to implement as follows
Public Readonly Property ProjectCategory As ProjectCategory Get If Me._ProjectCategory Is Nothing Then Me._ProjectCategory = ProjectCategoryBLL.GetProjectCategoryByID(Me._ProjectCategoryID) End If
[Code]...
I have my MODEL, BLL and DLL in separate projects and because of the fact that my BLL references my model I can not reference my BLL from my model as this would create a circular dependency.
I'm quite new to MVC and while I've been trying to follow the best practices , I believe I may not be understanding certain fundamentals of either
-a. Using models and viewmodels appropriately
-b. Passing models into a controller for validation purposes.
The general purpose of my program is to select a stored procedure from a list of stored procedures, create a form where the user can fill out all the appropriate input variables, and then to execute that stored procedure. The tool is for non-technical people, so I'm eventually going to have to do a good deal of input validation.
As such I have four models: A Script Model, a Parameter Model, a Parameter Enum model and a Query Model, and two viewmodels: a paramviewmodel that generates the form to fill out, and a scriptviewmodel that creates a listbox filled with the possible script choices. I am using a prewritten database system to fill out my viewmodels in an init method in my controller (which I'm not sure is the proper way to do this?).
The viewmodels are as follows:
Imports System Imports System.Collections.Generic Public Class ScriptViewModel
[Code]....
I'm trying to work out the functionality. Also, I think this may be too much code in the view, even though most of it is display code.
Anyways, I have two main questions. One, does creating a model in my controller, calling an init method on it, and then passing it to the view make any sense in an mvc context (if not, how would I proceed?). Two, if I want to perform validation on the form I output in my htmlhelper, but I want to use my query model validation (and not my paramviewmodel), how can I do that? Most of the examples I've seen involve a controller that recieves an appropriate model variable, and the binding is performed outside the controller itself. They then just check modelstate. Is there any way I could do something similar here?
Edit: Is there any way I can make the syntax highlighting less crappy?
I am trying to figure out the best way to implement a certain part of my model.I have an entity named Customer which has CustomerLocations (1-*) which have SalesOrders (1-*) which have Invoices (1-*).I want to allow them to have multiple addresses (Billing and Shipping) per customer and per location. I want to store those values in the sales orders and invoices, not a foreign key, what if they delete one of their addresses later down the road.I have tried complex types, but then they can't have multiple, can they? And having an Address entity, customer --> address (1-*) is ok, but a bit clumsy. How would you have a collection of billing and shipping addresses.?
