Re: Accessing function on Usercontrol hosted from Window in MVVM and C# - WPF Discussion Boards

Kind of understand some but still confused. Below is the class I'm constructing

C#

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Text;

namespace Manufactured_Housing_Manager
{
     public class ContactCollection : ObservableCollection<Contact>
    {
        #region left, right, mid string functions

        public static string left(string param, int length)
        {
            //we start at 0 since we want to get the characters starting from the
            //left and with the specified length and assign it to a variable
            string result = param.Substring(0, length);
            //return the result of the operation
            return result;
        }

        public static string mid(string param, int startIndex, int length)
        {
            //start at the specified index in the string and get the number of
            //characters depending on the length and assign it to a variable
            string result = param.Substring(startIndex, length);
            //return the result of the operation
            return result;
        }

        public static string right(string param, int length)
        {
            //start at the index based on the length of the string minus
            //the specified length and assign it a variable
            string result = param.Substring(param.Length - length, length);
            //return the result of the operation
            return result;
        }

        #endregion

         public ContactCollection() : base()
         {
             Add(new Contact("Davis, Adam T.", 0));
             Add(new Contact("Zappa, Frank M.", 1));
             Add(new Contact("Henry, Victor", 2));
             Add(new Contact("Vern, Jules W.", 3));
         }

    }

     public class Contact
     {
         private string _name;
         private int _id;
         public string Name
         {
             get { return _name; }
             set { _name = value; }
         }

         public int Id
         {
             get { return _id; }
             set { _id = value; }
         }

         public Contact()
         {
         }

         public Contact(string name, int id)
         {
             _name = name;
             _id = id;
         }
     }
}

Thing is I need to open my OLEDB Database to populate my dataset then I populate ObservableCollection<contact> with the names from each Contact in my database. I used the following code in the past to populate the tree and concate the names into one name information field I used to display.

C#

//add letters sort nodes
for (int i = System.Convert.ToInt32('A'); i <= System.Convert.ToInt32('Z'); i++)
{
    MyTreeView.Items.Add(new tvIndex(Convert.ToString((char)(i)), contactdata)); //set text

    //add customers
    contactdata = new ObservableCollection<Contact>();
    string sContactsName = null;
    foreach (DataRow rowContacts in Properties.Settings.Default.DtContacts.Rows)
    {
        sContactsName = string.Concat(rowContacts["LastName"].ToString(), ", ", rowContacts["FirstName"].ToString());

        if (!(System.Convert.IsDBNull(rowContacts["MiddleInitial"].ToString())))
        {
            if (!(rowContacts["MiddleInitial"].ToString() == ""))
                sContactsName = string.Concat(sContactsName, " ", rowContacts["MiddleInitial"].ToString(), ".");
        }

        if (left(sContactsName, 1) == Convert.ToString((char)(i + 1)))
        {
            string temp = rowContacts["ContactID"].ToString();
            contactdata.Add(new Contact(sContactsName, Convert.ToInt32(temp)));
        }
    }

In this way I simply added the base A-Z to the parent Node in the Treeview and then bound childnodes to the contactdata name and assigned the id to pull up the record.

My confusion stems from trying to implement the proper way of doing the same thing in this new public class based on ContactCollection : ObservableCollection<contact>.

As you can see I added a base which can manually add names and id's to the Collection. This gives me a certain amount of sample data to see if binding is correct. I should place my code here that imports my Dataset information, Concats the Last,First,MI into one name value and gives the id.

modified on Friday, August 12, 2011 4:35 PM

Ok, so your ROOT object is going to be a:

SortedDictionary<char, ContactCollection>

So you would do something like:

C#

SortedDictionary<char, ContactCollection> dict = new SortedDictionary<char, ContactCollection>();

for (int i = System.Convert.ToInt32('A'); i <= System.Convert.ToInt32('Z'); i++)
{
  ContactCollection cc = new ContactCollection();

  // add contacts with the last name starting with i to cc here
  foreach (...)
  {
  }

  dict.Add(System.Convert.ToChar(i), cc);
}

tv.ItemsSource = dict;

Your contact object also needs to implement INotifyPropertyChanged for this all to work correctly.

Report what your tree looks like on the screen and we can tweak the HierarchialDataTemplate to display the right content.

One last problem I think. How do I get tv.ItemsSource = dict;
to work. I get, An object reference is required for the non-static field, method, or property 'Manufactured_Housing_Manager.Outlookbar.MyTreeView'

I tried adding this to the tope of this class

using tv = Manufactured_Housing_Manager.Outlookbar;

also this is my xaml for binding

it's inside Outlookbar.xaml

HTML

<HierarchicalDataTemplate x:Key="ChildTemplate">
    <StackPanel Orientation="Horizontal">
        <Image x:Name="img2" Width="16"  Height="16" Stretch="Fill" Source="Images\closedfolder16.png" />
        <TextBlock Text="{Binding Path=Name}" Margin="5,0" ToolTip="{Binding Path=Name}"/>
    </StackPanel>
</HierarchicalDataTemplate>
<HierarchicalDataTemplate x:Key="MyTreeViewStyle"
                          ItemsSource="{Binding Path=Contact}"
                          ItemTemplate="{StaticResource ChildTemplate}">
    <!-- Display the Index by showing it's Index string -->
    <StackPanel Orientation="Horizontal">
        <Image x:Name="img" Width="16" Height="16" Stretch="Fill" Source="Images\closedfolder16.png" />
        <TextBlock Text="{Binding Path=Index}" Margin="5,0" ToolTip="{Binding Path=Index}"/>
    </StackPanel>
</HierarchicalDataTemplate>

modified on Friday, August 12, 2011 7:49 PM

I know I'm over thinking this. The whole Observable Collections thing is new to me. I'm confusing myself and getting discouraged. I created a hierarchical observable collection that worked before. but populating the class with data from my user selected OLE database was done outside the class. I can vaguely see how this is supposed to work , I'm just not visualizing the code to make it happen very well.

All of you help has been and is appreciated.

I was just showing you what property you needed to set. In proper MVVM, you don't set the ItemsSource explicitly. You just return it from your ViewModel.

public SortedDictionary<char, observablecollection<contact="">> ItemsSource
{
get
{
if (_dict == null)
{
// create the dictionary and observable collections here and
// store in _dict
}

return _dict;
}

then your XAML's DataContext should point to your ViewModel.

Then you can just do:

<treeview itemssource="{Binding" itemssource}="">

and your tree should be built for you.

You were talking about my needing to implement INotifyPropertyChanged, I've tried to use this before but I never was able to get it to work properly. How do you implement it and respond to it? I know that if I add or remove an item from my collection it will flag the INotifyPropertyChanged event. and I know that if I setup a function to respond to this it will run the code within it. But how do I use it actually?

If you use ObservableCollection, that already implements INotifyCOLLECTIONChanged for you. That will automatically update the UI when an item is added or removed. Your Contact object needs to implement INotifyPROPERTYChanged so the UI knows when a property of the contact object has changed. See this for a basic example: http://msdn.microsoft.com/en-us/library/ms229614.aspx[^].

For both INotifyPropertyChanged and INotifyCollectionChanged, you do not need to do anything else beyond implement the interfaces. When you bind to stuff, the WPF infrastructure will subscribe to the necessary events and do its thing for you.

This is what I came up with

C#

using System;
using System.Data;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Linq;
using System.Text;

namespace Manufactured_Housing_Manager
{
    public class Contact : INotifyPropertyChanged
    {
        private string _name = String.Empty;
        private int _id = 0;

        public event PropertyChangedEventHandler PropertyChanged;
        private void NotifyPropertyChanged(String info)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(info));
            }
        }  

        public string Name
        {
            get { return this._name; }

            set
            {
                if (value != this._name)
                {
                    this._name = value;
                    NotifyPropertyChanged("Name");
                }
            }  
        }

        public int Id
        {
            get { return this._id; }
            
            set
            {
                if (value != this._id)
                {
                    this._id = value;
                    NotifyPropertyChanged("Id");
                }
            }  
        }

        public Contact()
        {
        }

        public Contact(string name, int id)
        {
            _name = name;
            _id = id;
        }
    } 
}

My Xaml code is

HTML

<HierarchicalDataTemplate x:Key="ChildTemplate">
    <StackPanel Orientation="Horizontal">
        <Image x:Name="img2" Width="16"  Height="16" Stretch="Fill" Source="Images\closedfolder16.png" />
        <TextBlock Text="{Binding Path=Index}" Margin="5,0" ToolTip="{Binding Path=Index}"/>
    </StackPanel>
</HierarchicalDataTemplate>
<HierarchicalDataTemplate x:Key="MyTreeViewStyle"
                          ItemsSource="{Binding Path=Contacts}"
                          ItemTemplate="{StaticResource ChildTemplate}">
    <!-- Display the Index by showing it's Index string -->
    <StackPanel Orientation="Horizontal">
        <Image x:Name="img" Width="16" Height="16" Stretch="Fill" Source="Images\closedfolder16.png" />
        <TextBlock Text="{Binding Path=Name}" Margin="5,0" ToolTip="{Binding Path=Name}"/>
    </StackPanel>
</HierarchicalDataTemplate>

and the code Inside the UserControl is like this

C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.Collections.ObjectModel;

namespace Manufactured_Housing_Manager
{
    /// <summary>
    /// Interaction logic for Outlookbar.xaml
    /// </summary>
    public partial class Outlookbar : UserControl
    {        
        static public ObservableCollection<Contact> Contacts = new ObservableCollection<Contact>();

        public Outlookbar()
        {
            InitializeComponent();
            InitializeTreeview(); 
        }

        #region left, right, mid string functions

        public static string left(string param, int length)
        {
            //we start at 0 since we want to get the characters starting from the
            //left and with the specified length and assign it to a variable
            string result = param.Substring(0, length);
            //return the result of the operation
            return result;
        }

        public static string mid(string param, int startIndex, int length)
        {
            //start at the specified index in the string and get the number of
            //characters depending on the length and assign it to a variable
            string result = param.Substring(startIndex, length);
            //return the result of the operation
            return result;
        }

        public static string right(string param, int length)
        {
            //start at the index based on the length of the string minus
            //the specified length and assign it a variable
            string result = param.Substring(param.Length - length, length);
            //return the result of the operation
            return result;
        }

        #endregion

        private void InitializeTreeview()
        {
            Contacts.Add(new Contact("Davis, Adam T.", 1));
            Contacts.Add(new Contact("Zappa, Frank", 2));

            // This is where I need to add the code to populate the treeview with name data

 
            myTreeView.DataContext = Contacts;
        }

    }
}

In this way I can see the 2 contacts I have manually added but I still don't know how to get the base a-z stucture setup right in my Collection. also need to figure out how to only populate the treeview after I have opened the oledb database and populated the dataset.

This all works fine if I have everything in one class form but by having seperate usercontrols it's prving to be more difficult to do. If I had a static database to bind too it might be easier but I am allowing for user selected databases.

I have told you how a few times now Smile | :)

and even gave you the code last time.

You need to have *26* ObservableCollection<Contact>'s.

Your *ROOT* object needs to be a SortedDictionary<char, ObservableCollection<Contact>>.

You will insert 26 entries into the sorted dictionary. Key is 'A' - 'Z' and the value is a new ObservableCollection<Contact> that contains the last names starting with that key.

Thanks for all the help I have it working now! Smile | :)

Hello,
Listbox control is being populated from the xml file using WCF.
As I place the items inside the listbox, I also would like to assign a tag for each item.
How can I dynamically populate the tag for each item in the list please?
Thanks

There are several ways to do waht you want. I suppose the most application answer would be to ask what you want to set the tag to. It can be any object, and you could use data binding to accomplish your goal.

".45 ACP - because shooting twice is just silly" - JSOP, 2010
-----
You can never have too much ammo - unless you're swimming, or on fire. - JSOP, 2010
-----
"Why don't you tie a kerosene-soaked rag around your ankles so the ants won't climb up and eat your candy ass." - Dale Earnhardt, 1997

Hi,
How is it possible to fill a listbox with a colour?
I have populated the listbox but using the background colour does not fill all the background of each item.
How is this solved please?

Thanks

Try setting the item background to tansparent.

The chase down each element in item and make them transparent as well.

Never underestimate the power of human stupidity
RAH

Thanks

Hello Everyone,

I am viewing a pdf file which is generated in Temp folder in WebBrowser in WPF.

After viewing that there is a button for deleting that file. But while doing

File.Delete(filePath);

It gives me an error of Access denied.File is used by another process.

It is a AcrRdr which is locking the PDF file.but how to delete that file?

Thanks In Advance,
Ashish

I believe you must close the file so that it is no longer being viewed within the webbrowser, then you should be able to delete it.

Thanks,

I have done WebBrowser.Dispose(); and it releases the file.

But the webbrowser variable declared in XAML. I need to view another new file again it will not work since the object is Disposed.

Can you help me out how can I release PDF file? I have surfed on google It says AcrRdr holds the file since it is the last file.There is nothing where the browser can be redirected.

Help Needed please.

Regards,

Ashish

When you do WebBrower.Dispose(), you are "throwing out" your Web Browser control and all its content into the "trash can". All you have to do to release the PDF file it to close the file stream - something like pdfFileStream.Close(), with this you will be able to delete the PDF file and view another PDF file in your web browser

I am using

webbrowser1.source = filepath;

so there is not anything like filestream..

Before you delete set webbrowser1.source = null; or try = ""; the point is the system sees it as being used by the webbrowser control and therefore won't allow it to be deleted.

Thanks for reply..

I have tried Webbrowser1.source = null;

but its not releasing file.

Hi
I am looking for a open source project which is a vector editor (like MS Visio)using Silverlight. Any information will be appreciated.

Best regards,

I have some code written as such:

C#

public override void OnApplyTemplate()
{
    base.OnApplyTemplate();

    if ((object)Template != null)
    {
        CheckBox chkBox = Template.FindName("chkBox", this) as CheckBox;

        // do stuff with checkbox
    }
}

at runtime, this code works perfectly fine and everything is peachy. Inside of the designer, it apperently fails to find the CheckBox. I'm not really sure why... I can find parts that are in the "standard" template like Border "Bd" and ContentPresenter "PART_Header", but nothing in my overridden template.

Any ideas?

Hmm... kind of weird, but it seems like triggers aren't executed in the designer or something? I set the template via a trigger. If I hard code the template instead, it does show up... so it seems like my trigger isn't getting executed and its not picking my template.