Use of the TreeView in WPF

Because the TreeView control is needed in the project, because it is used in WPF for the first time, a lot of methods about data binding have been searched on the internet beforehand, and individuals have actually applied it, and feel that WPF The Hierarchicaldatatemplate definition template is a lot more useful, but today there is another way to do it in your own WPF+MVVM project. The code is inappropriate, look at enlighten.

First, data binding:

1, front desk xmal code: (no template definition used)

<treeview name= "TreeView"/>

/2, XAML Interactive logic CS code in the background adds a data context and passes the TreeView as a parameter to the corresponding ViewModel

Public TreeView ()
{
InitializeComponent ();
This. DataContext = new TREEVIEWVM (This.treeview);
}

3. Define entity classes, examples here    

Contry: County entity Class (attribute description automatically extracts the description information of database fields, corresponding to the Contry table in the database)

public class Contry
{
public Contry ();

String Mc{get;set;}

int Id{get;set;}

int Parentid{get;set}

}

/4, implementing data Binding in TREEVIEWVM     

constructor to receive the TreeView object passed by the foreground.

Public Treeviewvm (TreeView tr)
{
This.treeview = TR;
Initialcommand ();
Refreshtreeview (); Refresh TreeView to get Data
}

<summary>
Create the item for the TreeView
</summary>
<param name= "" ></param>
<returns></returns>
Private TreeViewItem Createtreeviewitem (Contry cty)
{
TreeViewItem TVI = new TreeViewItem ();
TVi. Header = Cty. MC;
TVi. Tag = Cty;
TVi. isexpanded = true;//Set data list to expand
return TVI;
}

<summary>
Gets the first-level node in the TreeView and implements recursive traversal
</summary>
<param name= "Contrylist" ></param>
<returns></returns>
Public List<contry > Bind (List<contry > Contrylist)
{

Contrylist= diccachelist.instance.getlistbytablename<contry > (TRUE);//Gets a list collection of Contry data tables in the cached dictionary, The specific encapsulation method is omitted here;
var list = Contrylist.where (a = a.parentid== null | | a.parentid== "_"). ToList ();//The ParentID (parent ID) of the first-level node in the database is empty or "_", where the data collection of the first-level node is obtained;

if (list. Count = = 0)
{
return null;
}
List. ForEach (A =
{
TreeViewItem TVI1 = Createtreeviewitem (a);
Treeview. Items.Add (TVI1);
Finddownward (Contrylist, a.id, TVI1);
});
return null;
}

<summary>
Implementation method of Recursive traversal treeview
</summary>
<param name= "" ></param>
<param name= "id" ></param>
<param name= "TVI" ></param>
<returns></returns>
Public Contry Finddownward (list<contry> contrylist, string ID, TreeViewItem TVI)
{
if (contrylist = = null)
{
return null;
}
var list = Contrylist.where (a = a.parentid== ID). ToList ();

if (list. Count = = 0)
{
return null;
}
List. ForEach (A =
{
TreeViewItem Tvi2 = Createtreeviewitem (a);
TVi. Items.Add (TVI2);
Finddownward (Contrylist, a.id, TVI2);
});
return null;
}

<summary>
Get the TreeView list, refresh the list
</summary>
private void Refreshtreeview ()
{
var contrylist= diccachelist.instance.getlistbytablename<contry> (True);
Treeview. Items.clear ();
Bind (contrylist);
}

Use of the TreeView in WPF