Using .NET If Vs. IIf In Binding/rendering Expression?
Oct 8, 2009
I'm trying to bind UI controls to a business object exposed as a property on an ASP.NET page in a null-safe manner.Using the 'If' operator is null-safe, but results in compiler error:
Compiler Error Message: BC30201: Expression expected.Using 'IIf' succeeds, but isn't null-safe. I've tried both the render expression syntax ('<%= %>') binding expression syntax ('<%# %>'), but there was no difference.Can someone explain this inconsistency and perhaps provide an alternative?
Sample code:
This works:
<%=IIf(Me.Foo Is Nothing, "", Me.Foo.Id)%>
This throws the compiler error:
<%=If(Me.Foo Is Nothing, "", Me.Foo.Id)%>
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Aug 14, 2011
For adding some images to a WrapPanel, I'm trying to iterate through a collection. My TileCollection contains instances of a Tile class which has a ImageSource property. I've got it by doing all the stuff step by step - Create a new image 1, assign all the properties, create a bew binding 1, assign binding 1 to image 1, add image 1 to the panel, proceed with image 2, ... tons of code I want to shorten now. Here is what I've got so far:
For Each tile As Tile In TileCollection
MainPanel.Children.Add(New Image With {.Width = 80, .Height = 80, .Margin = New Thickness(10), .SetBinding = New Binding With {.Source = tile, Path = New PropertyPath("ImageSource"), .Mode = BindingMode.Default, .UpdateSourceTrigger = UpdateSourceTrigger.PropertyChanged)}})
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1) ."SetBinding" doesn't work in object initializer expression. Is there any workaround?
2) Is there any way to add a handler in object initializer expression, for e.g. capturing mousedown events?
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Nov 21, 2010
Im getting some VB.Net Late binding operations cannot be converted to an expression tree. errors, have search here on the site and can only find solutions to the SQL get data code, not to my problem. The error "Late binding operations cannot be converted to an expression tree." At all my x.NAME) lines !? Im new to this so can anyone say me why i get this error..
[Code]....
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Nov 19, 2010
I get this error "Late binding operations cannot be converted to an expression tree."
At all my x.NAME) lines !?
<div>Navn: <%: Html.EditorFor(Function(x) x.Name)%></div>
<h3>Adresse</h3>
<div>Linje 1: <%: Html.EditorFor(Function(x) x.Line1)%></div>
[Code].....
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Jul 26, 2010
I currently have a View in MVC where I pass a single set of data to the view. However, I've come across a problem where I am having to use a LINQ query within a For Each loop in the View to pull out additional information from a SQL View of data from another DB.
The error I'm getting is Late binding operations cannot be converted to an expression tree.
The particular snippet I'm encountering the error on is:
[Code]...
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Oct 29, 2011
is there any way that i could link/bind multiple binding source to only one binding source navigator?
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Jan 23, 2010
I got this Error. below is my code.
GenerateTheList is function.Need help
Private Sub buttGenerate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles buttGenerate.Click
Dim thread1 As New Thread(New ThreadStart(GenerateTheList))
thread1.Start()
End Sub
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Mar 21, 2010
While looking in the dataset designer for a database table I am doing in visual basic 2008 I found a line for expressions under the property menu for a specific column. I need to know the code that I would put in this expression line so that this column adds up the numbers I input into three other columns and displays that number in the column. I need it to automatically calculate this for each row in the database table.
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Oct 18, 2010
binding navigators, datagrid view, binding source are all sql database parts.Will these parts still work if you havent got sql on you pc and your not using an database file (.log and .mfd) and your not coding to them, im using MS Jet/Oledb to code to Excel.What not to put on an Employee evaluation: This employee has hit rock bottom and shows signs of starting to dig.
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Oct 12, 2010
I am trying to write following expression on a datacolumn. But it results in error:Replicate('*', nLevel) + NameWhere: Replicate() is a user defined function (in a module). nLevel and Name are two other columns in same data table.
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Jun 12, 2012
I am using Flee to build a formula builder. It works great but the only problem I'm facing is that Flee doesn't understand Generic Methods I guess. I have a function called IIf declared in the expression context I'm using. [code]How can I work around this. I mean cannot , in sense, write all possible overloads of the function of all .net primitive types. What approach should I take.
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Jul 2, 2011
Binding Master Table to TextBox and DateTimePicker and Binding Details Tables to Datagridview then Add / Update / Delete in both
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May 10, 2012
I am using IIS 5.1 on server 2000. I have set the asp.net page for custom error in IIS which is directing to C:InetpubwwwrootCustom_ ErrorIIS_Error.aspx. Custom error page appears when user keyin wrong password for 3 times.When i access the error page directly (for testing) from my laptop using following URL then i can see the page text and the text box.
//192.168.0.10/Custom_Error/IIS_Error.aspx
But when user keyin wrong password for 3 times, system shows the custom error page with text only and doesn't show the asp.net controls.Also, is there any way to show the local path from where the user has been redirected to the custom error page? For an example; we have got 10 folders under website called TestWeb, so when the user is accessing folder number (3) called webtest3 and custom error page should show webtest3 on the page.Can i do it either on asp.net or on asp classic page?
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Feb 16, 2011
Working on some UI stuff, but I am having a problem drawing 'Top rounded' rectangles when the two top corners are rounded. I have methods to draw all four corners rounded and bottom rounded rectangles and they render fine.
I have attempted the graphics methods in CreateTopRoundedRect() in a variety of different orders, drawing the other corner first, the bottom line first, the bottom line before the left line, etc. In this function you can see a diagonal line splitting the shape. If you were to switch the bottom and left lines only half of the shape would be filled.
[Code]...
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Jul 5, 2011
I'm getting a strange problem with an ASP.NET web application that is in production. The problem is that pages intermittently don't render correctly (see screen shot below). It isn't one particular page in the application or one particular use that is having the problem.
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Apr 16, 2009
i have looked all over and can not figure out how to use the firefox rendering engine in vb for my web browser?
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Jul 4, 2009
I have a web application that works in our stage/test environment fine but once we moved it to our production environment something weird happens. All the control ids change. a label went from ctl00_cphMainContent_lblPetName to _ctl0_cphMainContent_lblPetName. Why would this happen? What could cause something like this to happen. The only two differences I know of are the production environment has HTTPS and I've disabled debugging.
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Jul 26, 2010
I'm wondering what the best way to render a scene made up of multiple-sized tiles, from back to front, with different heights. [code] Objects are sorted based on not their initial X/Y value, but their X/Y+Height value. That way, objects are rendered based on where they 'touch' the playing field. E.g., X/Y = top of a tree object, X/Y = trunk of the tree object.People (including the player) will be just normal map objects that get rendered and updated within a huge sorted list every frame. Right now, fudging around with my code allows my Player (32x64 pixels) to stand infront of a building but has her feet get overlapped with a patch of grass, which doesn't work. However, changing the sorting algorithm makes the player disappear in the building but you can see her feet.Also, should my players be included with the list of map objects? Granted, these will only be graphical representations of their data stored elsewhere (won't be cleared when map changes), or should I throw them into a whole new rendering list (which might open whole new problems). url...From what he says, he has 4 different layers and then draws the actor between Layer 3 and 4, with layer 4 being objects that will always appear on-top of the person.So, it appears that his player isn't a map object but an actor rendered separately from everything else.
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May 20, 2011
I'm trying to paint a cell indicating the progress with number and drawing a background like a progress bar. When I change the cell value it changes the background ok but thnumber looks awfull, only when the percentage bar reaches the number it looks ok, also if i minimisize the form and maximize it, all controls look with the
Private Sub dgLine_CellPainting(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellPaintingEventArgs) Handles dgLine.CellPainting
[code]....
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Apr 18, 2012
I'm trying to create a list of labels and textboxes. No errors but they aren't rendering on the form. I have confirmed my loop have values[code]...
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Dec 23, 2011
I'm having a few problems with the layout of my new browser. I have a WebBrowser control which is docked 'Fill', and a MenuBar at the top docked 'Top'. When I run the program and go to Google (which has a dark bar at the top), a white gap becomes visible. I think that this is because the MenuBar's RenderMode is set to 'System'. When I click on it in the editor the bottom of the background is a few pixels away from the MenuBar's bounding square.Also, the MenuBar's RenderMode has to be set to System other wise the control is drawn as a rounded-rectangle and there are gaps in the background image in the corners. That said, I could change it, if someone could provide a solution to showing the background image in another control and set the MenuBar's background to transparent.
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Nov 2, 2011
I have been reading the various blog posts on how to deal with a Complex Type. However I don't really get it. I am using EF code first development, MVC and VB. From what I have read so far to render a editor field for a complex types requires a custom object, right? However I don't really understand what code I need to put into the custom template. What code needs to go into custom template so I can render a textbox for the PostTags icollection?
My classes:
Public Class Post
Inherits EntityBase
<Key()> Property PostId As Integer
<DisplayName("Title")> <Required()> Property PostTitle As String
<UIHint("MultilineText")> <DisplayName("Text")> Property PostText As String
Code] .....
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Jun 21, 2010
I'm in essense trying to make my own interpretation of the NES hardware, so I can make a game that ideally would resemble what a NES game would look like. I'm currently stuck with how to adjust how to draw the playfield to the video memory (back buffer).
Backbuffer: The NES had restrictions on the nametable, or backbuffer. For my example, the backbuffer is 256x240pixels big, or the size of one screen. If I drew this to the TV, it would fill up the screen perfectly. Now, if I drew this to the screen with an offset of X=5, the entire image would be shifted and would wrap around the screen.
For example.....
ORIGINAL, NO OFFSET: DRAWN WITH OFFSET OF X=5:
ABCDEFGHIJK GHIJKABCDEF
DRAWN WITH OFFSET OF X=-5:
FGHIJKABCDE
The screen is split up into squares 8x8 pixels each, totalling 32x30 rows and columns. (256x240 pixels). The offset is represented in pixels - not columns; so in theory, I could offset the screen by 5 pixels and every column would be shifted to the right by five pixels.
Level Design: My stages are made up of screens, containing data that is represented in 16x15 rows and columns, each by 16x16 pixels. This is to emulate how many NES games stored level data - each tile holds info about what should be in each 8x8 block.
E.g.:
AA
BC with A,B,C,D representing what 8x8 graphic should go where
Level design is represented by this as well, with each number being a different screen and - meaning nothing, null.
-----
-123-
---4-
--54-
-----
Character Replacement: This is easy. I already know how I can determine which table, row, and column my characters are on based on their absolute positioning. I can also determine the relative positioning within the screen.
With this info, I can easily figure out which columns are to the left and right of the character, if any (if the character is at the left side of screen 1, thered be no more level left). How do I draw my levels to the screen, so that they scroll from one to the next. It would be relatively easy to draw one full screen at a time, and when the character gets to the edge just flip to another screen. However, the problem I'm conceptually having is that I need to 'stream' the level data onto the screen. That, lets say the character moves 24 pixels to the right. The BG needs to move as well. So, I need to adjust the scrolling of the backbuffer by 24 pixels.
However, just scrolling alone will cause the screen to wrap over, diplsaying old portion of the level. So, while scrolling I need to make sure to draw new pieces of the level to the back buffer. But before I can do that, which tiles need to get drawn first. And if the person goes 24 pixels to the left, I need to redraw tiles onto the backbuffer and change the offset accordingly as well. And let's not forget that if the character moves right and there's no more level data to be drawn, there should be no offset but instead the character gets closer to the side of the screen (instead of being centered in the middle of the screen via the X axis).
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Aug 20, 2010
The short is that I have a temperature model that calculates steel temperatures inside of a furnace at specific points inside a cross section. Typically, the nodes are 7x11, but I'm using a 3x3 here for simplicity. What I've done (and shout out if there's a better way) is to create an in-memory bitmap of that size (3x3), and set each pixel to a specific temperature-based color. Then I the form's Paint event handler to get a graphics object and render the bitmap to the size of the form's client area. Here's my simple code:
Public Class Form1
Private Const m_PixelRows As Integer = 3
Private Const m_PixelColumns As Integer = 3
[Code]...
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Feb 19, 2012
I've pulled down a webpage using a WebRequest object, and need to parse it, but first I need to render it since there is scripting on the page. I don't want to use the WebBrowser control because that forces me to jump out of my current function to the DocumentCompleted event, and "lose my place" (so to speak). Is there any way for me to pull down a URL using a WebRequest object and have the page rendered but still stay in my function?
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Aug 4, 2009
I am Using VS.NET 2008 VB - I am trying to render graphics from an off screen form or an invisble panel as comparison to as the previous version of VB (5.0,6.0) can use an invisible picture boxes to blt from. The problem that I am having that does not make much sense is that when the form is actually off the screen the blt returns nothing. Is there a new GDI+ operation that can copy from an invisible panel or picturebox or offscreen visble form or is there another low level api call that can be used to return what should be drawn on the off screen form or an invisble device context... Its a shame to see certain fetures of VB degrade. Like transparency and zorder. I would probably been done with my app if it werent for the setbacks. Can anyone offer any assitance? I do have it working correctly to display the transparency correctly but I am looking for a way to eliminate the flicker that is generated by setting the order and visiblit of the controls to render proper transparency... An offscreen form with a panel with all the controls to endure the flicker while I copy the images that was captured during the rendering process after it is done changing the depth order and visiblity would make the most sense
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Oct 21, 2011
I am generating an RSS feed using MVC 3, VBNET and EF. However when i view the feed url in IE, its not being rendered properly - all i see is a string of text and HTML tags have been encoded. [code]...
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Jul 23, 2009
I am having some problems rendering text in my program. I wrote an independent program to illustrate the problem. For some reason when using Direct3d.Font.Drawtext method with Arabic characters it comes out really wierd. [code]
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Apr 30, 2009
I am trying to make a graphics program with mousewheel-controlled zooming using GDI+. My plan is to provide rapid feedback, such as a low resolution render or even just a bounding rectangle, followed by a full resolution render as soon as possible afterwards. It seems logical to me to try a BackgroundWorker for the latter task. This is my first attempt to use one of these, or any other way of multithreading for that matter. Mousewheel events can follow one another much more quickly than I can render to the screen. That means I need to kill any rendering process that is already running and start a new one with the latest value of the zoom scaling factor.[code]The above class coexists with a DrawingSurface class, a UserControl which listens for the ProvideFeedback and ScaledImageReady events and paints the image accordingly. It also raises mouse/keyboard events for the zoom and other tools to deal with. My problem arises in the DO loop waiting for Cancellation to finish. The zooming routine works for one or maybe half a dozen renders, depending on the image size, but then it hangs in that loop and never comes out.
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Feb 22, 2009
From this code
[Code]...
If I put New Action(AddressOf PrivateMesage), then I get the following error: Bounds can be specified only for the top-level array when initializing an array of arrays. on the following code
[Code]...
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