Silverlight 4: Need help with Iteration

I'm having trouble with thinking of a solution that I'm trying to build, maybe someone here is able to guide me to the right direction.

I have a list of processes that belong to a processflow, these processes might have childs, and these childs might also have childs and so on.

The list looks like this:

ProcID     ChildOFID
1          0 (means no child)
2          1
3          2
4          3
5          3
6          5

As you can see Proc "3" contains 2 childs, of which one (5) also has a child (6).

I want to iterate over this list and draw objects for them on a canvas.

Right now I have the following code but it requires me to write up a loop for every level that I want to show.

int prev_location_left = 0;            
        int prev_location_top = 0;

        // Select Last ProcessStep (has no PreID!)
        var lastProcess = (from p in processlist
                           where p.PreID == 0
                           select p).FirstOrDefault<ProcessStep>();

        if (lastProcess != null)
        {
            create_processStep(lastProcess.ProcessID,
                                lastProcess.Name,
                                lastProcess.ProcessTypeID,
                                (900),
                                (30),
                                lastProcess.CummulativeCT,
                                lastProcess.WaitingTimeActual,
                                lastProcess.ValueAddTimeActual,
                                lastProcess.ProcessStepTime);

    开发者_高级运维        prev_location_left = 900;
            prev_location_top = 30;
        }

        // Select all the ProcessSteps that are a child of the last(first) one.
        var listChilds = (from p in processlist
                          where p.PreID == lastProcess.ProcessID
                          select p);


        int childscount = listChilds.Count();
        int cnt = 0;

        foreach (ProcessStep ps in listChilds)
        {
            create_processStep(ps.ProcessID,
                ps.Name,
                ps.ProcessTypeID,
                (prev_location_left - (150) ),
                (30 + (60 *cnt)),
                ps.CummulativeCT,
                ps.WaitingTimeActual,
                ps.ValueAddTimeActual,
                ps.ProcessStepTime);


            var listChilds2 = (from p in processlist
                              where p.PreID == ps.ProcessID
                              select p);

            int cnt2 = 0;

            foreach (ProcessStep ps2 in listChilds2)
            {
                create_processStep(ps2.ProcessID,
                    ps2.Name,
                    ps2.ProcessTypeID,
                    (prev_location_left - (300) ),
                    (30 + (60 *cnt2)),
                    ps2.CummulativeCT,
                    ps2.WaitingTimeActual,
                    ps2.ValueAddTimeActual,
                    ps2.ProcessStepTime);


                var listChilds3 = (from p in processlist
                                   where p.PreID == ps2.ProcessID
                                   select p);

                int cnt3 = 0;

                foreach (ProcessStep ps3 in listChilds3)
                {
                    create_processStep(ps3.ProcessID,
                        ps3.Name,
                        ps3.ProcessTypeID,
                        (prev_location_left - (450)),
                        (30 + (60 * cnt2)),
                        ps3.CummulativeCT,
                        ps3.WaitingTimeActual,
                        ps3.ValueAddTimeActual,
                        ps3.ProcessStepTime);
                    cnt3 = cnt3 + 1;
                }


                cnt2 = cnt2 + 1;
            }


            cnt = cnt + 1;
        }

So what needs to be done is the following:

• Get last process (the one with PreId == 0)
• Check what his childs are and draw them on canvas: Left -150, first child on Top 30, Second on Top 90, Third on Top 150 and so on.

Now for every child found I also need to check if they have childs and do the same logic again, i'm having trouble making this a sort-endless loop.

Help! :)

You could create a recursive parent/child object and bind to it with your view. Below is a very basic example using the data that you've provided.

MainPage.xaml

<UserControl x:Class="SilverlightApplication4.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
xmlns:local="clr-namespace:SilverlightApplication4"
d:DesignHeight="300" d:DesignWidth="400">

<UserControl.DataContext>
    <local:MainPage_ViewModel/>
</UserControl.DataContext>

<Canvas>
    <local:RecursiveView DataContext="{Binding RecursiveObject}"/>
</Canvas>

MainPage_ViewModel.cs

public class MainPage_ViewModel
{
    public MainPage_ViewModel()
    {
        List<KeyValuePair<int, int>> collection = new List<KeyValuePair<int, int>>()
        {
            new KeyValuePair<int,int>(1,0),
            new KeyValuePair<int,int>(2,1),
            new KeyValuePair<int,int>(3,2),
            new KeyValuePair<int,int>(4,3),
            new KeyValuePair<int,int>(5,3),
            new KeyValuePair<int,int>(6,5)
        };

        KeyValuePair<int, int> parent = collection.Where(kvp => kvp.Value == 0).First();
        collection.Remove(parent);

        RecursiveObject recursiveObject = new RecursiveObject()
        {
            root = parent.Key
        };

        populateChildren(recursiveObject, collection);

        this.RecursiveObject = recursiveObject;
    }

    public RecursiveObject RecursiveObject 
    {
        get { return recursiveObject; }
        set { recursiveObject = value; }
    }
    private RecursiveObject recursiveObject;


    private void populateChildren(RecursiveObject parent, List<KeyValuePair<int, int>> list)
    {
        List<KeyValuePair<int, int>> children = list.Where(kvp => kvp.Value == parent.root).ToList();
        children.ForEach(child => list.Remove(child));
        children.ForEach(child =>
        {
            RecursiveObject newChild = new RecursiveObject() { root = child.Key };
            parent.Children.Add(newChild);
            populateChildren(newChild, list);
        });
    }
}

RecursiveObject.cs

public class RecursiveObject
{
    public int root { get; set; }
    public List<RecursiveObject> Children 
    {
        get { return children; }
        set { children = value; }
    }
    private List<RecursiveObject> children = new List<RecursiveObject>();
}

RecursiveView.xaml

<UserControl x:Class="SilverlightApplication4.RecursiveView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
xmlns:local="clr-namespace:SilverlightApplication4"
d:DesignHeight="300" d:DesignWidth="400">

<StackPanel Margin="30,0,0,0">
    <TextBlock Text="{Binding root}"/>
    <ItemsControl ItemsSource="{Binding Children}">
        <ItemsControl.ItemTemplate>
            <DataTemplate>
                <local:RecursiveView DataContext="{Binding}"/>
            </DataTemplate>
        </ItemsControl.ItemTemplate>
    </ItemsControl>
</StackPanel>

Image of output:

I just placed a margin of '30' on the left of each child, but you could adjust it to be whatever you'd like. Not sure if this helps, I just thought it was a fun challenge to try :)