Re: How to connect a XPAP application to the Northwind database - WPF Discussion Boards

19-Jun-09 17:39

Please don't create a new account. You're the only person on EARTH who thinks it's wise to mix a 'browser application' ( i.e. you will put a web browser control in a window ), with a database.

CBenac wrote:
Data Source=TOSHIBA_PC\SQLEXPRESS

Is this your local machine ? Have you tried logging in with a username and password ? Have you googled the error message to see possible solutions ?

Christian Graus

Driven to the arms of OSX by Vista.

"! i don't exactly like or do programming and it only gives me a headache." - spotted in VB forums.

I can do things with my brain that I can't even google. I can flex the front part of my brain instantly anytime I want. It can be exhausting and it even causes me vision problems for some reason. - CaptainSeeSharp

[Message Deleted]

CBenac20-Jun-09 3:13

Re: Problem with WPF Browser application

20-Jun-09 3:13

[Message Deleted]

Christian Graus20-Jun-09 11:32

20-Jun-09 11:32

A WPF browser application runs in the browser ? I would assume that the issue is the application being sandboxed then.

Re: [Message Deleted]

Christian Graus20-Jun-09 13:09

How to connect a XPAP application to the Northwind database

20-Jun-09 13:09

I'm sorry if I misunderstood you at first, someone else has been posting about a browser application in WPF, and asking the same thing for days. I am trying to help you here, there's no need to delete your posts, or feel unwelcome. I am sorry for the misunderstanding, I do suspect that you're saying the app is running inside your browser, and that sandboxing is why you can't access a local DB, but you can probably access a network one. Have you had any luck with that avenue ?

CBenac20-Jun-09 15:34

Re: How to connect a XPAP application to the Northwind database

20-Jun-09 15:34

There is a sample application that uses the DataGrid (from the WPF Toolkit) and displays the customers table from the NorthWind database. It runs fine if it is created as an EXE which is the original intention of the author. However, since I need the application to run in the browser, I recreate the same project as a XPAP but the browser displays the bellow error message (snipet) from the "More information" link. It appears to be a connection issue with the database. I'm using Windows authentication mode.

>>
..
The action that failed was:
Demand
The type of the first permission that failed was:
System.Data.SqlClient.SqlClientPermission
The first permission that failed was:
<IPermission class="System.Data.SqlClient.SqlClientPermission, System.Data, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"
version="1"
AllowBlankPassword="False">
<add ConnectionString="Data Source=TOSHIBA_PC\SQLEXPRESS;Initial Catalog=Northwind;Integrated Security=True"
KeyRestrictions=""
KeyRestrictionBehavior="AllowOnly"/>
</IPermission>
.....
>>

The sample code was retrieved from here:
http://www.codeproject.com/KB/WPF/WPFDataGridExamples.aspx

Christian Graus21-Jun-09 0:39

Re: How to connect a XPAP application to the Northwind database

21-Jun-09 0:39

OK - well, if you're in the browser, then I assume you're serving your app over the web. You're going to need a connection string that connects to a remote machine, not one that relies on Windows security, because the browser is sandboxed from the rest of the machine. It's basically the security in the browser that is hitting you. Have you tried using a username/password to connect to the DB ?

CBenac21-Jun-09 12:58

Re: How to connect a XPAP application to the Northwind database

21-Jun-09 12:58

I changed from Windows to SQL Server authentication and logged as User: sa and the password, but it didn't make any difference. I'll look into this remote machine you mentioned. But any additional sugestion is welcomed. It is surprise to me the few online documentation regarding WPF.
Thanks so far for your input.

CBenac22-Jun-09 8:28

22-Jun-09 8:28

Christian,

I changed the properties of the application to "Full trusted site" and it worked nicely Smile | :)

Thanks for your help

CBenac

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19-Jun-09 10:48

N_tro_P

19-Jun-09 10:48

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Christian Graus19-Jun-09 11:02

19-Jun-09 11:02

You need to remember the size of the image itself, then you need to calculate the size of the canvas and work out a ratio to calculate a pixel position. If the aspect ratio is different, you need to work out if you use the width or the height to calculate position, and if you did any centring of the image, you need to calculate that offset, too.

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19-Jun-09 11:13

N_tro_P

19-Jun-09 11:13

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Christian Graus19-Jun-09 11:25

19-Jun-09 11:25

Welcome to hell. Width is the one you can set, but ActualWidth is the one that contains the width of the control. I believe the idea is, you can set what width you want, but you're not necessarily going to get it. I've had trouble, for example, placing an image in a grid. If they grid has no explicit size, even if it's told to stretch itself, you can put a BitmapImage in the Image, you can even set the Width of the Image, and the Height, but ActualWidth will stay zero.

ActualWidth is the one that you always use to know what the Width is.

Message Removed

19-Jun-09 11:28

N_tro_P

19-Jun-09 11:28

Message Removed

Christian Graus19-Jun-09 11:37

19-Jun-09 11:37

Glad to help.

How to remember the position of a GridSplitter

Mark Salsbery21-Jun-09 7:33

Mark Salsbery

21-Jun-09 7:33

This shouldn't be a "bumpy ride" if you understand how WPF layout works.

"There is a difference between the properties of Height and Width and
ActualHeight and ActualWidth. For example, the ActualHeight property is
a calculated value based on other height inputs and the layout system.
The value is set by the layout system itself, based on an actual rendering
pass, and may therefore lag slightly behind the set value of properties
such as Height that are the basis of the input change.

Because ActualHeight is a calculated value, you should be aware that
there could be multiple or incremental reported changes to it as a result
of various operations by the layout system. The layout system may be
calculating required measure space for child elements, constraints by
the parent element, and so on."

WPF: The Layout System[^]

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

fjparisIII19-Jun-09 8:57

fjparisIII

19-Jun-09 8:57

The goal is to remember the position of a GridSplitter from one execution of a window to the next so I can restore the previous position when the window reloads.

For purposes of discussion, assume my GridSplitter is vertical. I remember reading somewhere that to remember the position of the GridSplitter all you have to do is remember the width of the left element and when the window loads, set the element to that width.

However, my SizeChanged event for the left element only happens when the window is first loaded. Dragging the position of the splitter (hence changing the size of the left element - as well as the right element) does not generate any more SizeChanged events for the left element. That seems totally illogical.

Here is something else that seems totally illogical. I also tried getting MouseUp and MouseLeftButtonUp events for both the splitter and the Grid element the splitter is in, and I don't get any of these events either!

What could possibly be going on? The element that is in the left column of the Grid is a TreeView and I haven't even started populating it yet.

Re: How to remember the position of a GridSplitter (I "SOLVED" IT MYSELF)

fjparisIII19-Jun-09 11:37

fjparisIII

19-Jun-09 11:37

I searched the Code Project for the answer to this question and couldn't find one. I also Googled for it and found several proposed and confusing answers that I couldn't make much sense of. People don't seem to be very clear about what they really want. So I thought I'd ask the question on this Code Project WPF forum, but in the meantime I kept working on an answer myself. After trying a bunch of possibilities for a couple hours, I got the idea of remembering the width of the ColumnDefinition rather than the width of the element contained in the column. By itself, the latter doesn't work, but it does in conjunection with the former, depending on what you actually want to do. After receiving some success using the column definition, I ran into other problems, stemming from the fuzzy idea I had about the actual behavior I wanted. Eventually I defined that as follows, which may not be what you want:

Before my change, the position of my GridSplitter was automatically set to 1/3 the width of the grid and changing the width of the containing window maintained this 1/3 proportional ratio. I decided that for my application, this was undesirable behavior. I wanted the width of the left panel to remain fixed as the width of the window changed, and I wanted only the width of the right panel to change as I manually changed the width of the window. This required defining my grid columns as follows:

<Grid.ColumnDefinitions>
    <ColumnDefinition Name="treeColumn" Width="0"/>
    <ColumnDefinition Width="Auto" />
    <ColumnDefinition  Width="*"/>
</Grid.ColumnDefinitions>

The middle column corresponds to the GridSplitter. The width of the left column is set to 0 in this markup because that is actually the property I want to set programmatically in code-behind, both when the window is loaded and when the user drags the GridSplitter.

The only thing I had to work out is that the Width property of a ColumnDefinition is a GridLength object, not a simple double.

The other thing I had to figure out is what event to look for. I already explained in my initial post that SizeChanged on the element in the left column didn't work, and neither did MouseLeftButtonUp. I wasn't getting either event. That's because these are bubbling events that are being handled by higher level controls. I needed a tunneling event, a Preview event. For my purposes, PreviewMouseLeftButtonUp on the GridSplitter did the trick. Here is that event from my code-behind:

private void mainSplitter_PreviewMouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
    State.TreeWidth = treeColumn.Width.Value;
    treeCtrl.Width = frameForPages.Width - 16;
}

(The hard-coded 16 is a kludge: the hard-coded width of the left and right border. I'll clean this up later.) Now all I needed was the code to set the initial width of left column (treeControl) when my application started:

treeColumn.Width = new GridLength(State.TreeWidth);
treeCtrl.Width = frameForPages.Width - 16;

So now I know how to save the position of the GridSplitter from one invocation of its window to the next, and the next time someone searches for the answer to this question, hopefully he'll run into this post and see what some of the issues are that need to be addressed to accomplish the behavior he wants.

modified on Friday, October 30, 2009 12:12 PM

Re: How to remember the position of a GridSplitter (I SOLVED IT MYSELF)

Christian Graus19-Jun-09 12:46

Re: How to remember the position of a GridSplitter (I "SOLVED" IT MYSELF)

19-Jun-09 12:46

fjparisIII wrote:
Either I'm trying to do things that nobody knows the answer to or my questions are so stupid that people just laugh when they see them.

The traffic in this forum is pretty slow. However, there's a few people who are very good at WPF, and then there's me, who is doing his best. We'd all answer you, given a chance. Timezones mean you may need to wait a day.

You should use ActualWidth if it exists, rather than width. The preview events always fire, but the non preview events may not fire if something further up the tree consumes the event. Upshot is, I typically use the preview events only.

fjparisIII19-Jun-09 13:55

fjparisIII

19-Jun-09 13:55

Christian Graus wrote:
You should use ActualWidth if it exists, rather than width.

ColumnDefinition.Width is not the same as UIElement.Width. The latter is a double, the former is a GridLength and doesn't work the same way as a UIElement.Width. You can't use ActualWidth to solve this problem.

Christian Graus wrote:
The preview events always fire, but the non preview events may not fire if something further up the tree consumes the event. Upshot is, I typically use the preview events only.

As I explained above, this is because a tunneling event is needed here, i.e. a Preview event.

Re: How to remember the position of a GridSplitter (I SOLVED IT MYSELF)

Christian Graus19-Jun-09 17:37