How do I make validation rules work with two controls, Part 2 of 2

Question

(Part 1 is here: https://learn.microsoft.com/en-us/answers/questions/94723/how-do-i-make-validation-rules-work-with-two-contr.html)

I'm not sure this will help, but here's the code to the validation rule class I've defined:

using System;  
using System.Globalization;  
using System.Windows.Controls;  
  
namespace CoreFramework.ViewModel.ValidationRules  
{  
    public class MaxProficienciesValidationRule : ValidationRule  
    {  
        public long Min { get; set; }  
  
        public long SolutionID { get; set; }  
  
        public override ValidationResult Validate(object value, CultureInfo cultureInfo)  
        {  
            long proposedMaxProficiencies = 0;  
  
            if (SolutionID > 0)  
            {  
                return ValidationResult.ValidResult;  
            }  
  
            try  
            {  
                if (((string)value).Length > 0)  
                {  
                    proposedMaxProficiencies = Int64.Parse((string)value);  
                }  
                else  
                {  
                    return new ValidationResult(false, "Empty string invalid");  
                }  
            }  
            catch (Exception ex)  
            {  
                return new ValidationResult(false, $"Illegal character(s) or {ex.Message}");  
            }  
  
            if (proposedMaxProficiencies < Min)  
            {  
                return new ValidationResult(false, "MaxProficiencies must be greater than 0");  
            }  
  
            return ValidationResult.ValidResult;  
        }  
    }  
}  

I'm sure I'm going to have to define a converter class that will take the ValidationResult and converter it to a Thickness, but I'm not sure where to do that within the XAML.

Answer 1

Here is the code for demo.
Part 1: Code for MainWindow.xaml(ps: code for the picture which i can't paste here)

     <StackPanel>  
            <Border>  
                <TextBox x:Name="MaxProficienciesTextBox"  
                         Margin="0,5"  
                         MaxLength="2"  
                         >  
                    <TextBox.Text>  
                        <Binding Path="MaxProficiencies" UpdateSourceTrigger="PropertyChanged">  
                            <Binding.ValidationRules>  
                                <!--<local:MaxProficienciesValidationRule Min="1" SolutionID="{Binding SolutionID}" />-->  
                                <local:MaxProficienciesValidationRule Min="2" SolutionID="0" />  
                            </Binding.ValidationRules>  
                        </Binding>  
                    </TextBox.Text>  
                </TextBox>  
            </Border>  
        </StackPanel>  

Part 2 : Code for MainWindow.xaml.cs

 public partial class MainWindow : Window  
    {  
        MyModel myModel = new MyModel();  
        public MainWindow()  
        {  
            InitializeComponent();  
            this.DataContext = myModel;  
        }        
    }  
    
    public class MaxProficienciesValidationRule : ValidationRule  
    {  
        public long Min { get; set; }  
        public long SolutionID { get; set; }  
        public override ValidationResult Validate(object value, CultureInfo cultureInfo)  
        {  
            long proposedMaxProficiencies = 0;  
            if (SolutionID > 0)  
            {  
                return ValidationResult.ValidResult;  
            }  
            try  
            {  
                if (((string)value).Length > 0)  
                {  
                    proposedMaxProficiencies = Int64.Parse((string)value);  
                }  
                else  
                {  
                    return new ValidationResult(false, "Empty string invalid");  
                }  
            }  
            catch (Exception ex)  
            {  
                return new ValidationResult(false, $"Illegal character(s) or {ex.Message}");  
            }  
  
            if (proposedMaxProficiencies < Min)  
            {  
                return new ValidationResult(false, "MaxProficiencies must be greater than 0");  
            }  
  
            return ValidationResult.ValidResult;  
        }  
    }  

Part 3: Code for MymModel.cs

class MyModel : ViewModeBase  
    {  
        private long maxProficiencies;  
        public long MaxProficiencies  
        {  
            get { return maxProficiencies; }  
            set  
            {  
                maxProficiencies = value;  
                InvokePropertyChanged("MaxProficiencies");  
            }  
        }  
    }  
  
    class ViewModeBase : INotifyPropertyChanged  
    {  
  
        public event PropertyChangedEventHandler PropertyChanged;  
        protected void InvokePropertyChanged(string property)  
        {  
            if (this.PropertyChanged != null)  
            {  
                this.PropertyChanged.Invoke(this, new PropertyChangedEventArgs(property));  
            }  
        }  
    }  

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