WPF Discussion Boards

Databinding and Value Converter questions

Michael Eber4-Jan-10 10:39

4-Jan-10 10:39

OKAY -- I've done a ton of searching and I've not found anything that can directly help me with what I need to do.
I'm building a business application with Silverlight 3.0 and I'm down to my VERY LAST issue!

I have 3 ComboBox controls (building, datacenter, locationType) where datacenter has a dependancy on building.
I have a listbox with customers (works great).
When a customer is selected, a list of existing locations is populated. (works great)

For these (and other) populated controls, I put out a message "loading...blah blah blah" then when the data comes back I display "data loaded...blah blah blah" which works great.

I've got my datacenter dependancy working great as well. Pick a building and the correct set of datacenters is loaded.

My editor fields are wrapped in a grid and a datasource for my location object was created. I populate it in my code by setting editorContainer.DataContext = selectedCustomerLocation; editorContainer is the grid that wraps all of my editor controls. Each control that edits the fields of the control is bound to the datacontext of the grid, but Expression does not seem to place the parent object name as a fully-qualified name. (example my xaml says 'BuildingNumber' instead of CustomerLocation.BuildingNumber) I expected the editor controls to self populate with the data once DataContext was set. (doesn't work)

I also want each combobox to display the correct selected item. I know I need to say SelectedText = "{Binding {fieldName} Converter=myValueConverter, ConverterParameter= ....". I also expected that in the Convert logic I perform the linq to lookup the building enumerated object and return the text value for the integer returned in the customer location object.

Not quite sure how to explicitely pass to the converter the value of the building ID (for example) AND the list of building name/values to have it return the correct text. So this is the first question which is the syntax to pass parameters into the converter?

The second question, then, is Expression put the datacontext in a self-contained location within the grid followed by my fields. Do I have to extend the <datacontext> end tag to wrap my editor controls? Or is DataContext all wrong? I think I saw one guy use Data Template???

Any help at all would be great. I found a ton of examples but all of them are either too simplistic (working with internal collections statically created and never dealing with an externally selected object to bind with) or buried within the context of a DataGrid which I'm not using.

modified on Monday, January 4, 2010 4:53 PM

Re: Databinding and Value Converter questions

Abhinav S4-Jan-10 16:05

Abhinav S

4-Jan-10 16:05

Michael Eber wrote:
SelectedText = "{Binding {fieldName} Converter=myValueConverter, ConverterParameter=

A trick I used to pass multple values (my entire collection) to the converter was to not bind to the field name. Try this - SelectedText = "{Binding Converter=myValueConverter, ConverterParameter= ....".

Michael Eber wrote:
The second question, then, is Expression put the datacontext in a self-contained location within the grid followed by my fields. Do I have to extend the end tag to wrap my editor controls? Or is DataContext all wrong? I think I saw one guy use Data Template???

Not quite sure I understand your question. However, IMO, the datacontext looks fine. DataTemplates are used to specify the visual structure of a data object, so DataContexts and DataTemplates are actually two different things (used differently).

There are only 10 types of people in this world — those who understand binary, and those who don't.

Re: Databinding and Value Converter questions

Michael Eber5-Jan-10 6:27

Michael Eber

5-Jan-10 6:27

What I mean as far as passing data to the converter is this:
I need to pass the collection of objects that populate the dropdown box.
I also need to pass the value set by the object.
I've seen a setup like this for passing a date: ConvertParameter=0\d\ But I have no idea what that means or how they are actually passing the date field.

Re: Databinding and Value Converter questions

Abhinav S5-Jan-10 17:00

Abhinav S

5-Jan-10 17:00

Michael Eber wrote:
ConvertParameter=0\d

AFAIK, ConvertParameter does not support binding. So, you can only pass 'hardcoded' values like 0\d, which will format your date. The date is passed using the binding value e.g. Text="{Binding myDate, Converter={StaticResource myConverter}}".

However, the entire collection can be passed into the converter. The appropriate value(s) can then be used inside the converter to construct the value you want to display in your UI.

There are only 10 types of people in this world — those who understand binary, and those who don't.

GridSplitter Behaviour

rj_hogan4-Jan-10 5:35

rj_hogan

4-Jan-10 5:35

Hello,

I'm studying for the WPF exam and playing with the different setting in the GridSplitter control and one of the behaviours makes no sense to me.

Here is the XAML:

<Grid Name="grid1">
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="100" />
        <ColumnDefinition Width="5"/>
        <ColumnDefinition Width="173"/>
    </Grid.ColumnDefinitions>
    <Grid.RowDefinitions>
        <RowDefinition />
        <RowDefinition />
    </Grid.RowDefinitions>
    <ListBox Name="listbox1" Grid.Column="0" SelectionChanged="listbox1_SelectionChanged"></ListBox>
    <GridSplitter Name="gridsplitter1" Margin="0" Width="5" Grid.Column="1" Grid.RowSpan="2" ResizeBehavior="PreviousAndNext"  HorizontalAlignment="Left" VerticalAlignment="Stretch"/>
    <RichTextBox Grid.Column="2" Name="richtextbox1" />
    <TextBox Grid.Column="0" Grid.Row="1"/>
    <TextBox Grid.Column="2" Grid.Row="1"/>
</Grid>

When I use the splitter it resizes the previous column (0) but not the next (2), it just trundles across the window not changing size.

I know I can get the desired behaviour by just changing the third column to a proportional size but then it's the proportioning that is changing the column size not the splitter (and I'd get the same result if I put it back the ResizeBehavior to the default "BasedOnAlignment").

What am I missing here? Or is there no point to the PreviousAndNext setting?

Thanks,

Robert.
Robert

Re: GridSplitter Behaviour

Pete O'Hanlon4-Jan-10 9:25

Pete O'Hanlon

4-Jan-10 9:25

You have an absolute size for the last column. This size will be retained when you attempt the resize, hence the "move". Change it as follows:

<Grid Name="grid1" Width="278">
    <Grid.ColumnDefinitions>
       <ColumnDefinition Width="100"/>
       <ColumnDefinition Width="5"/>
       <ColumnDefinition Width="*"/>
    </Grid.ColumnDefinitions>
    <Grid.RowDefinitions>
       <RowDefinition/>
       <RowDefinition/>
    </Grid.RowDefinitions>
    <ListBox Name="listbox1" Grid.Column="0">
    </ListBox>
    <GridSplitter
       Name="gridsplitter1"
       Width="5"
       Grid.Column="1"
       Grid.RowSpan="2"
       HorizontalAlignment="Left"
       Margin="0"
       VerticalAlignment="Stretch"
       ResizeBehavior="PreviousAndNext"/>
    <RichTextBox Name="richtextbox1" Grid.Column="2"/>
    <TextBox Grid.Column="0" Grid.Row="1"/>
    <TextBox Grid.Column="2" Grid.Row="1"/>
 </Grid>

In order to see the effect, I limited your grid width to 278.

"WPF has many lovers. It's a veritable porn star!" - Josh Smith

As Braveheart once said, "You can take our freedom but you'll never take our Hobnobs!" - Martin Hughes.

My blog | My articles | MoXAML PowerToys | Onyx

Re: GridSplitter Behaviour

rj_hogan5-Jan-10 0:46

rj_hogan

5-Jan-10 0:46

Yes, I know about the using the * for the last column but I have two points of confusion with this.

1) The first column has an absolute size but it has no issue resizing that.

2) If we are going to set the 3rd column width to * we might as well go with the default ResizeBehavior of BasedOnAlignment as we will get exactly the same behaviour - hence why I wonder if PreviousAndNext has any purpose.

(I've explicitly set the ResizeBehavior but could have omitted it as BasedOnAlignment is the default):

<Grid Name="grid1">
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="100" />
        <ColumnDefinition Width="5"/>
        <ColumnDefinition Width="*"/>
    </Grid.ColumnDefinitions>
    <Grid.RowDefinitions>
        <RowDefinition />
        <RowDefinition />
    </Grid.RowDefinitions>
    <ListBox Name="listbox1" Grid.Column="0" SelectionChanged="listbox1_SelectionChanged"></ListBox>
    <GridSplitter  Name="gridsplitter1" Margin="0" Width="5" Grid.Column="1" Grid.RowSpan="2" ResizeBehavior="BasedOnAlignment" HorizontalAlignment="Left" VerticalAlignment="Stretch"/>
    <RichTextBox Grid.Column="2" Name="richtextbox1" />
    <TextBox Grid.Column="0" Grid.Row="1"/>
    <TextBox Grid.Column="2" Grid.Row="1"/>
</Grid>

Actually even if we use "BasedOnAlignment" but change the 3rd column back to an absolute width and set the HorizontalAlignment to "Right" it still won't resize the 3rd column, it just moves it across again. I can't see why there should be a difference in the behaviour (beyond which column is targeted) between setting the alignment to left or right.

Re: GridSplitter Behaviour

Pete O'Hanlon5-Jan-10 2:16

Pete O'Hanlon

5-Jan-10 2:16

Have a look at what happens if you add a second splitter. It's a bit of fun:

<Page xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
  <Grid Name="grid1">
    <Grid.ColumnDefinitions>
      <ColumnDefinition Width="100" MinWidth="100"/>
      <ColumnDefinition Width="5"/>
      <ColumnDefinition Width="173"/>
      <ColumnDefinition Width="5"/>
      <ColumnDefinition Width="*"/>
    </Grid.ColumnDefinitions>
    <Grid.RowDefinitions>
      <RowDefinition/>
      <RowDefinition/>
    </Grid.RowDefinitions>
    <ListBox Name="listbox1" Grid.Column="0">
    </ListBox>
    <GridSplitter
      Width="5"
      Grid.Column="1"
      Grid.RowSpan="2"
      HorizontalAlignment="Right"
      Margin="0"
      VerticalAlignment="Stretch"
      ResizeBehavior="PreviousAndNext"/>
    <GridSplitter
      Width="5"
      Grid.Column="3"
      Grid.RowSpan="2"
      HorizontalAlignment="Right"
      Margin="0"
      VerticalAlignment="Stretch"
      ResizeBehavior="PreviousAndNext"/>
    <RichTextBox Grid.Column="2"/>
    <RichTextBox Grid.Column="0" Grid.Row="1"/>
    <TextBox Grid.Column="2" Grid.Row="1"/>
    <RichTextBox Grid.Column="4"/>
    <TextBox Grid.Column="4" Grid.Row="1"/>
  </Grid>
</Page>

"WPF has many lovers. It's a veritable porn star!" - Josh Smith

As Braveheart once said, "You can take our freedom but you'll never take our Hobnobs!" - Martin Hughes.

My blog | My articles | MoXAML PowerToys | Onyx

WWF

Ramkumar_S3-Jan-10 14:36

Ramkumar_S

3-Jan-10 14:36

Hi All,

I need to create a editable Workflow in run time.
Is is possible?
Please help me with this.

Thanks in advance.

Ramkumar
("When you build bridges you can keep crossing them. ")

http://ramkumarishere.blogspot.com

Re: WWF

ProtoBytes4-Jan-10 3:52

ProtoBytes

4-Jan-10 3:52

Hmm Interesting... Well I would use reflections. Does it need to be a graphical work flow? If so there is a nice WPF Work flow front end here on CP that would work for the graphical front end. I am using it in a 'Visual Power Shell' article...

Here is the link to the work flow designer...

WPF Diagram Designer - Part 2[^]

How to animate To/From an Auto value?

spiritboy3-Jan-10 8:04

spiritboy

3-Jan-10 8:04

for example i want to animate the width of grid from 0 to its Auto Value! i've searched alot but cannot find anything, thanks in advance!

Re: How to animate To/From an Auto value?

Abhinav S3-Jan-10 16:39

Abhinav S

3-Jan-10 16:39

You will have to apply a resize animation.
Check this out[^].

There are only 10 types of people in this world — those who understand binary, and those who don't.

creating GridViewColumn.CellTemplate via C# ?

Mohammad Dayyan2-Jan-10 23:43

Mohammad Dayyan

2-Jan-10 23:43

Hi everybody.
I'm gonna create a ListView in WPF like below image via XAML and C#

http://xs.to/image-A835_4B3EF7EE.jpg[^]

I've already read some articles like this one[^] , but I'm a little confusing.
Could you please guide me , how I can do it ?
Thanks.

Dynamic data binding in WPF application

anishshrestha2-Jan-10 5:57

anishshrestha

2-Jan-10 5:57

I am trying to develop a quiz application for the children using WPF and Expression Blend. What actually happens in the quiz is the textblock with the question hovers in the screen for certain time and the children have to click the correct answer of this Multiple choice question. After that certain time the question and the multiple choice answer options has to be updated from the XML data source.

Using the concept of data context I have data bind the XML with the UI but I could not yet dynamically bind to it. Any help would be highly appreciated.

Thank you in advance.

Re: Dynamic data binding in WPF application

Pete O'Hanlon2-Jan-10 7:06

Pete O'Hanlon

2-Jan-10 7:06

Take a look into using the Model View ViewModel (MVVM) pattern. There are lots of links on Google about using MVVM in WPF.

"WPF has many lovers. It's a veritable porn star!" - Josh Smith

As Braveheart once said, "You can take our freedom but you'll never take our Hobnobs!" - Martin Hughes.

My blog | My articles | MoXAML PowerToys | Onyx

Re: Dynamic data binding in WPF application

Mark Salsbery2-Jan-10 7:13

Mark Salsbery

2-Jan-10 7:13

anishshrestha wrote:
Using the concept of data context I have data bind the XML with the UI but I could not yet dynamically bind to it.

What do you mean by "dynamically bind to it"?

Programmatically you can create a Binding object, set its properties
as needed, and then set the binding to the property on the element:

Binding binding = new Binding();
binding.XPath = "Name";
myTextBlock.SetBinding(TextBlock.TextProperty, binding);

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

Re: Dynamic data binding in WPF application

anishshrestha2-Jan-10 8:36

anishshrestha

2-Jan-10 8:36

For the application, Actually I wish to move to the next question from the XML node as soon as a the time limit is up and so the options for that particular question. I seem to have no idea how to accomplish that in code.

How is it possible to bind the different node of data from the XML, one at a time,for a same control after the certain time gap???

Thank you for the response. I would appreciate any help or suggestions.

Thank you.

Resolution setting in WPF

Anu_Bala31-Dec-09 18:33

Anu_Bala

31-Dec-09 18:33

Hi,

In my applcaiton,i make Grid of size Grid Width="1300.441" Height="80",
Its working fien in this resolution.But when i changed my resolution to 1152 width,quater of application get out of the desktop.
How can i avoid that?
I want to display full page in all resolution.
Pls help me

Anu

Re: Resolution setting in WPF

Mark Salsbery1-Jan-10 9:10

Mark Salsbery

1-Jan-10 9:10

Anu_Bala wrote:
How can i avoid that?

Don't use hard-coded dimensions.

Instead, use an element that sizes the Grid.

For example, if the Grid is the child of a Window element,
you could set the Window's WindowState to Maximized and the Grid
will fill the Window's client area.

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

Silverlight combobox in aspx page

Shivan Nandan31-Dec-09 18:32

Shivan Nandan

31-Dec-09 18:32

Hi friends,

I am new to silverlight. I have created a silverlight combo with options 'Male' and 'Female', and included it in an aspx page.
Now I want to know, how to retrieve the selected value and selected text in aspx code.

Please help me.

Shivanandan C V

Re: Silverlight combobox in aspx page

Mark Salsbery1-Jan-10 9:01

Mark Salsbery

1-Jan-10 9:01

Shivan Nandan wrote:
how to retrieve the selected value and selected text in aspx code.

aspx code runs on the server and Silverlight runs on the client.

You can use javascript on the client to communicate with a
Silverlight plugin.

HTML Bridge: Interaction Between HTML and Managed Code[^]

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

Re: Silverlight combobox in aspx page

April Fans6-Jan-10 19:12

April Fans

6-Jan-10 19:12

You can use javascript. Detailed info can be found at:

http://pietschsoft.com/post/2008/06/Silverlight-and-JavaScript-Interop-Basics.aspx

April

Comm100 - Leading Live Chat Software Provider

modified 27-May-14 21:45pm.

Google map in wpf application

vsaratkar31-Dec-09 8:16

vsaratkar

31-Dec-09 8:16

Hi,

I have a list of locations, I want to use google map for routing thro' the locations to find the shortest path, get directions and see street view using google API. This a wpf application, I am downloading locations from server.

As far as possible we don't want to use WebBrowser control.

Is there any way to do this? Any help or related link will be greatly appreciated.

Thanks!!
Happy new year

Veena

Re: Google map in wpf application

Mark Salsbery31-Dec-09 13:02

Mark Salsbery

31-Dec-09 13:02

A bunch of ideas...[^]

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

Re: Google map in wpf application

Mohammad Dayyan31-Dec-09 20:48

Mohammad Dayyan

31-Dec-09 20:48

Have you seen http://greatmaps.codeplex.com/[^] ?

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