Odtnhj

im new to WPF MVVM

i have 3 classes here (All classes have same BaseParent):

---- The Problem is ---->
Whenever i set my BaseParents GroupContent in [DPropertyViewModel], it doesnt update my ConsoleText in [DConsoleViewModel].

Model:

 public class BaseDParent

 public string GroupType get; set; = "None";

 public string GroupName get; set; = "None";

 public string GroupContent
 
 get => _groupcontent;
 set
 
 _groupcontent = value;
 SetContent();
 
 
 private string _groupcontent;

ViewModel:

 public class DConsoleViewModel : DNotify

 public BaseDParent DElement
 
 get => _delement;
 set
 
 _delement = value;
 NotifyPropertyChanged();
 
 
 private BaseDParent _delement;

 public string ConsoleText
 
 get => DElement.GroupContent;
 set
 
 DElement.GroupContent = value;
 NotifyPropertyChanged();
 
 

and here is where i change my BaseParents GroupContent:

public class DPropertyViewModel : DNotify

 public BaseDParent DElement
 
 get => _delement;
 set
 
 _delement = value;
 NotifyPropertyChanged();
 
 
 private BaseDParent _delement;

 public string Level get; set; = "0"; 
 public string Property get; set; = "Property"; 
 public string Value get; set; = "-Null-";

 public void SetDElementPropertyValue()
 
 string startline = " " + DElement.GroupType + " " + DElement.GroupName + DHelper.NewLine();
 string subpropline = DHelper.NewLine() + Level + " " + Property + " ";

 int start = DElement.GroupContent.IndexOf(startline);

 int propstart = DElement.GroupContent.IndexOf(subpropline, start - 3) + subpropline.Length;
 int propnext = DElement.GroupContent.IndexOf(DHelper.NewLine(), propstart);
 string propvalue = DElement.GroupContent.Substring(propstart, propnext - propstart);

 string toremove = subpropline + propvalue + DHelper.NewLine();
 int toaddindex = DElement.GroupContent.IndexOf(toremove);
 DElement.GroupContent = DElement.GroupContent.RemoveSub(toremove);

 string toadd = subpropline + Value + DHelper.NewLine();
 DElement.GroupContent = DElement.GroupContent.Insert(toaddindex, toadd);
 

Thanks for your help :)

The INotifyPropertyChanged interface is used to notify clients, typically binding clients, that a property value has changed. - Microsoft Docs on INotifyPropertyChanged

Your model BaseDParent is where you should be implementing INotifyPropertyChanged because this is where the values are changing, not in the ViewModel.

You can then remove ConsoleText from your ViewModel and bind directly to BaseDParent.GroupContent for your output.

As it currently stands, your DElement property on DConsoleViewModel is raising changes relating to the object reference itself. e.g. from null to a constructed version of BaseDParent.

Microsoft Docs on the subject: https://docs.microsoft.com/en-us/dotnet/api/system.componentmodel.inotifypropertychanged?view=netframework-4.7.2