WPF Discussion Boards

31-Mar-13 3:44

Hi Guys, I have a nice working app in Windows Forms. I am attempting to port it to WPF and I am stuck with selecting a row and getting a value from one of the columns.

Apologies for the long code:

In Windows Forms App I do the below:

private void lstFiles_DoubleClick(object sender, EventArgs e)
{
    if (lstFiles.SelectedItems.Count != 0)
    {
        string file = lstFiles.SelectedItems[0].Text;
        openFormGeneral(file);
    }
}

In WPF .xaml:

<ListView x:Name="lstFile" Height="357" HorizontalAlignment="Left" Margin="18,144,0,0" VerticalAlignment="Top" Width="550"
          ItemsSource="{Binding songDetails}"
          MouseDoubleClick="lstFile_MouseDoubleClick"
          IsSynchronizedWithCurrentItem="True"
          SelectedItem="{Binding Path=SelectedSong}">
    <ListView.View>
        <GridView>
            <GridViewColumn CellTemplate="{StaticResource FirstCell}" Width="30" />
            <GridViewColumn Header="File Name" DisplayMemberBinding="{Binding FileName}" />
            <GridViewColumn Header="Title" DisplayMemberBinding="{Binding Title}" />
            <GridViewColumn Header="Artist" DisplayMemberBinding="{Binding Artist}" />
            <GridViewColumn Header="Album" DisplayMemberBinding="{Binding Album}" />
            <GridViewColumn Header="Set" DisplayMemberBinding="{Binding Set}" />
            <GridViewColumn Header="Genre" DisplayMemberBinding="{Binding Genre}" />
            <GridViewColumn Header="Language" DisplayMemberBinding="{Binding Language}" />
            <GridViewColumn Header="File Path" DisplayMemberBinding="{Binding FilePath}" />
        </GridView>
    </ListView.View>
</ListView>

I Populate the ListView as follows:

public class songDetails
{
public string Title { get; set; }
public string Artist { get; set; }
public string Track { get; set; }
public string Set { get; set; }
public string Album { get; set; }
public string Genre { get; set; }
public string Language { get; set; }
public string FileName { get; set; }
public string FilePath { get; set; }
}

public IList<songDetails> songDetail { get; set; }


public void AddFile(ID3Info File)
{
    lstFile.Items.Add(new
    {
        FileName = File.FileName,
        Artist = File.ID3v2Info.GetTextFrame("TPE1"),
        Title = File.ID3v2Info.GetTextFrame("TIT2"),
        Track = File.ID3v2Info.GetTextFrame("TRCK"),
        Album = File.ID3v2Info.GetTextFrame("TALB"),
        Genre = File.ID3v2Info.GetTextFrame("TCON"),
        Language = File.ID3v2Info.GetTextFrame("TLAN"),
        FilePath = File.FilePath
    });

    artist = File.ID3v2Info.GetTextFrame("TPE1");
    track = File.ID3v2Info.GetTextFrame("TRCK");
    set = File.ID3v2Info.GetTextFrame("TPOS");
    title = File.ID3v2Info.GetTextFrame("TIT2");
    album = File.ID3v2Info.GetTextFrame("TALB");
    genre = File.ID3v2Info.GetTextFrame("TCON");
    language = File.ID3v2Info.GetTextFrame("TLAN");

    InitializeComponent();
    this.DataContext = this;
}

How do I access the FilePath from the ListView with MouseDoubleClick event? Thanks in advance

Excellence is doing ordinary things extraordinarily well.

Mycroft Holmes31-Mar-13 12:39

31-Mar-13 12:39

You bound the SelectedSong so SelecedSong.FilePath should contain your information provided you double clicked on a row so test for null!

Never underestimate the power of human stupidity
RAH

MumbleB1-Apr-13 0:34

1-Apr-13 0:34

Hi Mycroft. Thanks for the reply. This may sound stupid but how do I do that? I have tried numerous things and nothing works or I get a very long string of all the items in the object returned. Frown | :(

Excellence is doing ordinary things extraordinarily well.

Mycroft Holmes1-Apr-13 1:23

1-Apr-13 1:23

Wherever this property (SelectedSong) is declared is where you object is

SelectedItem="{Binding Path=SelectedSong}"

In your doubleclick event you need to reference the SelectedSong

string sPath = class.SelectedSong.FileName

If you are using MVVM then class = your viewmodel.

Never underestimate the power of human stupidity
RAH

MumbleB2-Apr-13 9:10

2-Apr-13 9:10

Hi Mycroft. Apologies for taking this long to reply. Been a little busy. I tried the below and I get the SelectedItem but it does not get passed to "theSong". Am I going crazy or am I just missing the point completely here?

private void lstFile_MouseDoubleClick(object sender, MouseButtonEventArgs e)
{
    try
    {
        var theSong = this.lstFile.SelectedItem as songDetails;

        if (theSong != null)
        {
            string filePath = theSong.FilePath;
        }
    }
    catch (Exception ex)
    {
        System.Windows.Forms.MessageBox.Show(ex.Message.ToString());
    }

}

Excellence is doing ordinary things extraordinarily well.

Mycroft Holmes2-Apr-13 12:15

2-Apr-13 12:15

You are missing the point completely Smile | :)

you are thinking like winforms, stop.

You should not/never be referencing the controls in the view but the collection it is bound to in you viewmodel or code behind. Stop trying to get the info from the list control and look in the SelectedSong property where you have bound the SelectedItem to!

Never underestimate the power of human stupidity
RAH

MumbleB3-Apr-13 7:27

Collection of User Controls

3-Apr-13 7:27

I bound the SelectedSong to a textBox and it works now. Not the cleanest way of doing things but it works.

Thanks

Excellence is doing ordinary things extraordinarily well.

modified 3-Apr-13 17:25pm.

Mycroft Holmes30-Mar-13 22:44

30-Mar-13 22:44

I have a requirement to display a collection of sections, each section needs needs to show a few combos, a couple of large textboxes, probably a grid and support drag and drop files.

I was thinking of using a listbox of user controls, the user control would be an expander (telerik) with all the bits in it.

My issues is how to put together the collection/control/viewmodel. Building the VM that accepts a SelectedSection and loads the static lists for the combos etc is not a problem. I can then bind the view datacontext to the viewmodel.

I would then use the UC as the datatemplate of the listbox. How do I bind the SectionsList collection to the listbox and the UC data template.

Are there any good examples of this!

Never underestimate the power of human stupidity
RAH

SledgeHammer0131-Mar-13 14:48

31-Mar-13 14:48

You should not expose a collection of user controls, or any control for that matter. Define a class called Section (whatever the hell that is) that contains all the data for a section. Then define an ObservableCollection<Section> and expose that from your VM and bind it to the ListBox ItemsSource. Then simply define the ItemTemplate for the ListBox and you are good to go.

Your ItemTemplate would define the controls and their layout and bind them to the Section object which will be the ListBoxItem content.

Mycroft Holmes31-Mar-13 14:55

31-Mar-13 14:55

This is fine for a standard list of items, I need a UC and a VM for each item in the list.

Never underestimate the power of human stupidity
RAH

SledgeHammer0131-Mar-13 15:13

31-Mar-13 15:13

Not quite sure what you mean. When you say "UC", you should be using a DataTemplate that defines that "UC". When you say "VM" for each item, that would be your Section object. In fact, if you want to argue semantics, your DataTemplate could just be your user control. It would inherit the DataContext.

Mycroft Holmes31-Mar-13 15:30

31-Mar-13 15:30

My section object is a Model, basically a POCO with onpropertychanged events.

Main View has an observable collection of Sections, these are to be displayed in a list/tree container that needs to contain a set of controls (UC) for the management of the section contents.

UC UserControl will be a set of controls required for each section (datatemplate), including combos and a drag and drop target, an expander and some large textboxes.

The UC will need bind to a ViewModel to manage the Section interactions. How to achieve the binding is my problem!

Never underestimate the power of human stupidity
RAH

SledgeHammer0131-Mar-13 15:43

31-Mar-13 15:43

Sounds like we are saying pretty much the same thing, but you don't like my semantics lol Smile | :)

.

Ok, so Section is a model an observable POCO. Check.

UC UserControl = DataTemplate for an item.

Here is where you are arguing semantics. You say you need a VM for binding to the UC UserControl / DataTemplate... I'm agreeing with you, but saying it needs to be part of Section. Then you can bind as normal.

If you still want to argue semantics, you can do something like:

class Section
{
public Prop1
public Prop2
public Prop3
ViewModelBase ViewModel;
}

and then in your XAML, you could either do:

<MyUserControl /> and the DataContext will point to the Section object and you can reference the VM from there using Path=ViewModel.Blah;

Or if you want to be pedantic, you can do:

<MyUserControl DataContext="{Binding ViewModel}" />

and the MyUserControl will only get the ViewModel rather then the whole Section object. Either way works, but the VM / sub object / whatever you want to call it, has to be part of Section since that is what you are binding to.

If you don't want to do that for whatever reason, the only other thing you can probably do if you want to get all tricky is use DataTemplates to instantiate the VMs based on something in the Section object, but that would require modifying how the item creation works and the end result will be that you could have just stuck your "VM" into the section object and achieved the same thing and kept a few more hairs Smile | :)

Mycroft Holmes31-Mar-13 15:59

31-Mar-13 15:59

Ah I think I see where I am diverging, my Section object is part of the ViewModel whereas your Section object would contain the ViewModel.

So the collection of Section objects should include the POCO AND the VM functionality, in my architecture this is then a collection of VMs which becomes the DataContext for CollectionControl.

Have a bunch of 5s - thank you!

Never underestimate the power of human stupidity
RAH

SledgeHammer0131-Mar-13 16:20

31-Mar-13 16:20

You got it Smile | :)

.

Calling something a ViewModel is just arguing semantics. Its just some random (generally observable) object that the DataContext points to. In the MVVM world its just some random (always observable) object that derives from "ViewModelBase" or something similiar.

The VM that owns the listbox would have the ObservableCollection<Section>. Section would then contain the VM / whatever for the UserControl.

Mycroft Holmes31-Mar-13 18:02