I am setting my viewmodel as datacontext in my xaml but I override it to my view to make few functions work however to achieve the visibility on some grids and I have a property in my VM can I override my datacontext back to my VM? If so how? I have a stackpanel that has datacontext overriden as my grid and within that stackpanel I need to change the datacontext for a button.
View 1 RepliesI'm going through an XML file of articles and the journalist(s) that wrote them. As we are adding the articles into _Data our datacontext we may come across a journalist that needs adding so we do this: [code] However subsequently we may come across this same journalist again and nothing is returned when we do this: [code] So it uses the code above again to insert the same journalist again.Once all of our inserts are done we do a submitchanges. At this point it has a head fit:INSERT statement conflicted with COLUMN FOREIGN KEY constraint 'FK_ articles_ journalists_journalists'. The conflict occurred in database 'blah', table 'journalists', column 'id'. The statement has been terminated.From looking through the sql generated in sql profiler you can see that it is trying to add some journalists more than once, this will fail as the name must be distinct. The subsequent records that are trying to be inserted with these journalists are failing as the journalist wasn't updated.Surely if I have a collection of journalists, add some to it and then look in my collection I should see all of them and not just the original ones.
View 3 Replies<ItemsControl DockPanel.Dock="Top" ItemsSource="{Binding Path={x:Static vmc:clsPersonViewModel.ChildrenPath}, Mode=OneWay}">
<ItemsControl.ItemTemplate>
[Code].....
In the code above, if there are no children (the ChildrenPath property returns NULL), nothing is rendered in the view. In the code below, when ChildrenDataSetPath is NULL the XamDataGrid still gets rendered. How do I achieve the same for a single object (as opposed to a collection) as the datacontext?
<DataTemplate DataType="{x:Type vmb:clsPersonViewModel}">
<igDP:XamDataGrid DataSource="{Binding Path={x:Static vmb:clsPersonViewModel.ChildrenDataSetPath}}">
[Code].....
I have a context menu on my DataTemplete for a list box, and that menu will contain links to Favourite and Retweet the tweet (the menu item) But I don't know how to get the information about the Tweet in code. I am trying the following Line:
[Code]...
I have some data in my Linq.DataContext.I had succes in converting it to an XSD - Schema, using the following code:
Dim changeset As System.Data.Linq.ChangeSet = c.GetChangeSet()
Dim objDic As New Dictionary(Of System.Type, List(Of Object))
If Not changeset Is Nothing AndAlso Not changeset.Inserts Is Nothing AndAlso Not
[code].....
I would like to know if its possible to discard changes of only one record of only one table in datacontext. I use databind to bind my controls on a form. I modify one record at a time. after the modification, the user have to hit save button to validate. But he can hit cancel. I would like that the cancel button discard all the changes that the user has done. Is it possible?
View 3 RepliesI asked a question earlier where I was told a simple way to "bind data to objects" is to just run a SqlConnection(connectionString). The response also included a comment saying I could get fancy with L2S and Entity Frameworks, so I looked deeper into those. It seems all you have to do with the DataContext object is point to the database. Why would SqlConnection be a benefit? What is the difference (or pros/cons) of using either one of these? Is one more "standard"? Is one more modern?
View 1 RepliesHow to bind a textbox in design view to a LINQ to SQL datacontext class?
View 3 RepliesUPDATE: See the bottom of this question for what I did to solve the problem.I'm trying to understand how the ItemsSource and DataContext properties work in a Silverlight Toolkit DataGrid. I'm currently working with dummy data and trying to get the data in the DataGrid to update when the value of a combo box changes.
View 2 RepliesI have an object that may have been inflated via a plain old DataContext, or may just have been new-ed up with just its .ID property set. There's no way to know for sure. I'm looking to rehydrate the entire object from whatever is in the database. If the object was new-ed up, I can call .Attach() on the table object and refresh from the Data Context with no trouble. But, if the object was already inflated from the DataContext I get the error: "Cannot attach an entity that already exists.". There's no timestamp field or anything like that - just an integer primary key being used to control the rehydration. I'd like to know if there's a way to conditionally attach. Here's the code - it works the way I want it to, but this seems a hackish way to go about it:
' myDC is a shared instance of a vanilla DataContext...
' myObj is an instance of a linqed-up `SomeLinqObject`
Dim tbl = myDC.GetTable(Of SomeLinqObject)()
[Code[,,,,,
I'm trying to find a way to have the DataContext available from within Entities.
I want to do something like this:
partial public class MyEntity
public DataContext as MyDataContext
private sub OnLoaded()
[Code]....
This should be pretty easy, but it throws VS2008 for a serious loop.I'm trying out WPF with MVVM, and am a total newbie at it although I've been developing for about 15 years, and have a comp. sci. degree. At the current client, I am required to use VB.Net. I have renamed my own variables and removed some distractions in the code below, so please forgive me if it's not 100% syntactically perfect! You probably don't really need the code to understand the question, but I'm including it in cas.
I have a very simple MainView.xaml file:
<Window x:Class="MyApp.Views.MainView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
[code].....
I am preparing to deploy a web service that uses SqlConnection primarily as its means to get to the database, and I am adding some new methods that use a DataContext instead of thatand the default constructor and DBML file would use a connection string refering to my development machine (I believe...)
View 1 RepliesI am new to WPF and the MVVM design pattern this month, and more than a little out of practice in general. To learn, I've been playing around with textboxes, rectangles, and ways to display them in a window. I began with Ashley Davis' excellent "Simple Drag Selection in WPF" tutorial, which walks through creating a view model for a collection of rectangles, binding a listbox to said collection, and styling the listbox with a canvas, creating a data template for the rectangles, as well as basic "rubber band" selection logic.
I have since built on this tutorial to improve the drag selection so that it behaves much more like selection does in windows explorer, and to allow resizing the rectangles from the corners or edges.All was well until I changed the MainWindow.xaml in an effort to include a column on the side for various buttons and controls, thus moving the "editor surface" grid from inside a 1x1 grid on the main window to a column of a 1x2 grid, moving the data template to the grid's resources (since it will be the only element in the window that needs it). As soon as I did this, subroutines that I wrote which interact with the listbox started misbehaving--rubber band selection no longer works. There's no visual indication that listbox items are being selected (they were highlighted previously), and interrogating listBox.SelectedItems.Count after a drag-selection mouseUp event returns a zero.
After some experimentation, reading many questions on this site and sections of my WPF Unleashed book, and going over the msdn databinding overview, as of this morning I still cannot find my mistake(s). I believe it is a data binding mistake or incorrect data context.Some details about the view models involved:
DataFieldViewModel
...implements INotifyPropertyChanged and exposes properties for its (in this case a rectangle and a textbox) X,Y position, width, height, visibility, and selection status (a way to track it across several rubber band selection operations)
PageViewModel
...implements INotifyPropertyChanged, and has among other things an ObservableCollection of type DataFieldViewModel, called DataFields, and exposes it as a ReadOnly Property.Here's a look at MainWindow.xaml.vb and one of the broken subs:
Namespace EditorUI
'
' The main window of the editor.
[code]....
I have a LINQ to SQL DataContext with all my tables and all my stored procedures in it. Let me first start off by saying that we are upgrading our project from an access project to a WPF project. So in the Access project you could set a forms datasource to a stored procedure and edit and add new information. So in my WPF project on the page load I call my stored procedure to return an ISingleResult and then call a function to set the binding on every single textbox on the form. One is there an easier way to do this and two what if I want to add a new record since the textbox's are binded to an ISingleResult?
View 2 RepliesIs there a way to translate this code in VB? Most of it is easy, but I can't figure out a way to override the event handler.
public class MTObservableCollection<T> : ObservableCollection<T>
{
public MTObservableCollection()
{
[code]....
Protected Overrides Sub Dispose(ByVal disposing As Boolean)
Try
If disposing = true And components IsNot Nothing Then
components.Dispose()
End If
Finally
MyBase.Dispose(disposing)
End Try
End Sub
Error: Protected Overrides Sub Dispose(disposing As Boolean)' has multiple definitions with identical signatures.How can I call this without raising an error ?
Some of my DataGridViewCells return the wrong value in their GetClipboardContent method. They are cells in a DataGridViewComboBoxColumn cells, so they use the displayed property, not the value property of the cell. I want it to return the value itself.An initial attempt was simply using
Protected Overrides Function GetClipboardContent(ByVal rowIndex As Integer, ByVal firstCell As Boolean, ByVal lastCell As Boolean, ByVal inFirstRow As Boolean, ByVal inLastRow As Boolean, ByVal format As String) As Object Return Value End Function in my DataGridViewComboBoxCell descendant but then I noted that this method is called more than one time per cell value, once for every data format DataGridView supports by standard, which are format="HTML", "Text", "UnicodeText" and "Csv". For csv, the base implementation appends a comma if it's not the last cell, for html it adds the correct tags depending on if it's the first/last row/cell in the table/table row, etc. I consider this format-specific, not cell-value specific.
So how could I replace the value that ends up in the clipboard without re-implementing all those format-specific aspects? That would result in quite some code for functionality that already exists in the base class, wouldn't it?
I have a theoretical class Name_Order, that has a string Name and a int Order. I need to indicate that two Name_Order's are different, if the pair NameOrder is different, that is, or name or order are different. Now, overriding Equals no problemo, but I have some "issues" with GetHashCode:
[Code]...
I have a main class that has a Sub procedure with no implementation. Any derived class should override and implement this procedure, so I used MustOverride in the base class.
Now, any time this procedure is called, I need to set a specific Boolean variable to True at the beginning of the procedure and set it to False at the end.
Is there a way to avoid writing these two lines of code in procedure implementation of every single derived class? Can I set this value to True in the base class, then run procedure in the derived class and then set the value back in the base class?
I inherited DataGridViewTextBoxCell because I need to add some custom property to it.
At run-time after creating the DataGridView instance and bind the data I do the following:
For k As Integer = 0 To grid.Columns.Count - 1
grid.Columns(k).AutoSizeMode = DataGridViewAutoSizeColumnMode.ColumnHeader
If k > 0 Then grid.Columns(k).CellTemplate = New CustomCell()
Next
[Code]....
the cell type is never of type CustomCell but it remains DataGridViewTextBoxCell.
Is it the best override for Equals (in VB.NET) for an object having an unique ID? [code]I took that example from the MSDN, but not entirely sure if from all points of view (including performance) is the better solution.[code]
View 2 RepliesI know how to handle overriding form closing with FormClosing event and MessageBox prompt by setting e.cancel to true but how can I override deactivation of the mdi child form?
View 3 RepliesI have a DataViewGrid that is populated with emp records sorted by a 'header' record listing the managers name. Currently, the user is a ble to select any row, even the manager row. I want to modify the program to prevent users from being able to select the manager record or 'header' record
View 9 RepliesI have an access database for steel members. Each table has a different type of member, and then in those tables, each size of that member type.
I am about to create a tool that draws these sections when they are selected, but as there are 12 different member types, I don't really want to have 12 different Subs for "Draw" that essentially do the same thing.
I considered polymorphism.. (I think I have it correct)
[code...]
I have a DGV with the Alternating row color set to grey.In the CellFormatting event on the DGV I want to go through the rows as if a cell contains a certain value I want to set the BackColor to red.However when I do this, it just gets overridden with the Alternating grey color. The cell in question in a normal colored row appears in red as expected, just not the alternating row.
rticularly when creating jQuery buttons with no text and just icons) as a result of this.Secondly I am attempting to create my own custom button output by overriding the Render() event and am having a bit of difficulty trying to understand how to go about changing the output that is provided by this event.If I look at the HtmlTextWriter that is provided as the parameter to the Render() event I can see it contains a protected property TagKey = Input {47}, is it possible to simply modify this property somehow and change it to a Button or do I need to create a new instance of the HtmlTextWriter and populate it all from the start? If so, could anyone provide some guidance as to how this would typically be done and if there are any special considerations I need to make to ensure that my derived button class is functionally equivalent to the original (excluding the html)?
<Assembly: TagPrefix("MyCompany", "MyCustomButton")>
Public Class MyButton
Inherits Button
[code].....
I would like to use the windows messagebox with for exampleyes' and 'no' buttons on it, but I want to be free to choose the lanuage on the buttons.I mean 'Ja' and 'Nein' or 'Oui' and 'Non' instead of the systems default language.
View 2 RepliesI've overriden the WndProc of the ComboBox and I am drawing my own combo box, a code snippet is below:
Protected Overrides Sub WndProc(ByRef m As Message)
MyBase.WndProc(m)
Select Case m.Msg
Case &HF
[Code]....
Though the old control is still being painted as my drawn combo box is just overlapping the old drawing. Is there a way to stop it drawing the default combo box?
I was asked to build a winform exe that receives arguments from a web service and decide in which mode the application should start.what is the best way to design and build the application?The application needs to receive 3 arguments.
User name. - stringApplication mode - Boolean (user read write privileges)List on string.
Where do I receive this arguments in the new method ?