Range validator in MAUI Blazor

Question

Here is a simple app to Add numbers from 0 to 100 , after which I like to perform some statistical operations.

Add Insert works fine , I can restrict only 0 to 100

Delete works fine.

When editing it is accepting all numbers , I like to restrict 0 to 100,please suggest.I am looking something like a range validator to restrict my input from 0 to 100.

@page "/Range"
 
<PageTitle>Probability</PageTitle>
 
<ul>
    @foreach (var todo in todos)
    {
        <li>
            <input type="checkbox" @bind="todo.IsDone" />
            <input   @bind="todo.Title"  />
        </li>
    }
</ul
<ul>
    @foreach (var todo in listsort)
    {
        <li>
            
            <input readonly @bind="todo.Title" />
        </li>
    }
</ul>
<input placeholder="Something todo" @bind="newTodo" />
<button @onclick="AddTodo">Add</button> <br>
<button @onclick="DeleteTodo">Delete</button>
<p>To Delete Check the Box </p>
<div>
    Range:
  </div>
<div>
    @ran
    </div>
<div>
        @errmsg
    </div>
@code {
    public class TodoItem
    {
        public int Title { get; set; }
        public bool IsDone { get; set; }
    }
    private List<TodoItem> todos = new();
    private List<TodoItem> listsort = new();
    private int newTodo; int rancnt;
    private string errmsg;private string skip; private int max;private int ran;
    private void DeleteTodo()
    {
        int rem = todos.Count((s => s.IsDone == true));
        if (rem > 0)
        {
            var toRemove = todos.Where(todos => todos.IsDone == true).ToList();  
            foreach (var s in toRemove)
            {
                todos.Remove(s);
            }
        }
        listsort = todos.OrderBy(p => p.Title).ToList();
          rancnt = todos.Count();
         if (rancnt >0)
         { 
        ran =   todos.Max(p => p.Title)-todos.Min(p => p.Title) ;
         }
    }
    private void AddTodo()
    {errmsg = "";
        skip = "N";
        errmsg = "";
        if( (newTodo <= 0) ||   (newTodo > 100)) 
        { skip = "Y"; 
        errmsg = "Enter number between 0 and 100";}
        
   //   int cnt  = todos.Where(todos => todos.Title ==newTodo).Count();
    //  if (cnt>0)
    // {  
   //  errmsg = "Number already exists";}
       
  if(skip=="N")
  { 
        todos.Add(new TodoItem { Title = newTodo });
  }
        newTodo = 0;
        listsort = todos.OrderBy(p => p.Title).ToList(); 
        rancnt = todos.Count();
         if (rancnt >0)
         { 
        ran =   todos.Max(p => p.Title)-todos.Min(p => p.Title) ;
         }
    }
    
    
}

Answer 1

As said By AgaveJoe I will try to capture the validation during Submit.

@page "/Range"
 
@using System.ComponentModel.DataAnnotations;  
 
  
<PageTitle>Probability</PageTitle>
 
<ul>
    @foreach (var todo in todos)
    {
        <li>
            <input type="checkbox"  @bind="todo.IsDone" />
            <input  readonly @bind="todo.Title"  />
        </li>
    }
</ul
<input placeholder="Something todo" @bind="newTodo" />
<button @onclick="AddTodo">Add</button> <br>
<button @onclick="DeleteTodo">Delete</button>
  <div>
   Ascending Order  
  </div>
 <ol>
    @foreach (var todo in listsort)
    {
        <li>
            
            <input readonly @bind="todo.Title" />
        </li>
    }
</ol>
<button @onclick="Submit">Perform Calc</button>
<div>
    Range:
  </div>
<div>
    @ran
    </div>
      <br />
    <div>
    Count:
  </div>
<div>
    @rancnt
    </div>
 
         <br />
    <div>
    Sum:
  </div>
<div>
    @meansum
    </div>
         <br />
    <div>
    Mean:
  </div>
<div>
    @calcmean
    </div>
         <br />
  <div>
    Mode(s)
  </div>  
  
  <div>
  <ul>
     
    @for  (int i = 0; i < myNum.Length; i++) 
    {
            <li>
                @if(display=="Y")
                { 
               @myNum[i] 
                }
             
            </li>
    }
       
</ul>
 </div>  
  <br />
  <div>
      Median
      </div>  
      <div>
    @calcmedian
    </div>
<div>
  
        @errmsg
    </div>
 
@code {
    public class TodoItem
    {
        public int Title { get; set; }
        public bool IsDone { get; set; }
    }
    public class  Groups
    {
        public int Title { get; set; }
    }
    public class  Summary
    {
        public int Title { get; set; }
        public int cnts { get; set; }
    }
    private List<TodoItem> todos = new();
    private List<TodoItem> listsort = new();
    private int newTodo; int rancnt; int meansum;
    private string errmsg;private string skip; private int max;private int ran; private decimal calcmean; private decimal calcmedian; int median = 0; private int[] myNum = { 0  }   ;
    private List<Groups> modegroups = new();
    private List<Groups> tempgroups = new(); private string display = "N"; private int[] medarr; 
    private List<Summary> sumgroups = new();
    protected override void OnInitialized()
    {
    }
    private void DeleteTodo()
    {
        display = "N";  
        ran = 0;
        rancnt = 0;meansum = 0; calcmean = 0;calcmedian = 0;
        int rem = todos.Count((s => s.IsDone == true));
        if (rem > 0)
        {
            var toRemove = todos.Where(todos => todos.IsDone == true).ToList();  
            foreach (var s in toRemove)
            {
                todos.Remove(s);
            }
        }
        listsort = todos.OrderBy(p => p.Title).ToList();
    }
    private void AddTodo()
    {     display = "N";
        myNum[0] = 0;
        ran = 0;
        rancnt = 0;meansum = 0;calcmean = 0;calcmedian = 0;
        errmsg = "";
        skip = "N";
        errmsg = "";
        if( (newTodo <  0) ||   (newTodo > 100)) 
        { skip = "Y"; 
            errmsg = "Enter number between 0 and 100";}
        int cnt  = todos.Count();
        if (cnt>20)
        {   skip = "Y"; 
            errmsg = "Cannot enter number more than 20 numbers";}
        if(skip=="N")
        { 
            todos.Add(new TodoItem { Title = newTodo });
        }
        newTodo = 0;
        listsort = todos.OrderBy(p => p.Title).ToList(); 
    }
    private void Submit()
    { display = "Y";
        meansum = todos.Sum(p => p.Title) ;
        rancnt = todos.Count();
        if (rancnt >0)
        { 
            ran =   todos.Max(p => p.Title)-todos.Min(p => p.Title) ;
            calcmean = Math.Round( Decimal.Divide(meansum ,  rancnt),2)  ;
            //
            var tempgroups =listsort.GroupBy(n => n.Title)
                             .Select(n => new
                             {
                                 Title = n.Key,
                                 TitleCount = n.Count()
                             })
                             .OrderBy(n => n.Title);
          //  sumgroups = tempgroups;
            int groupmax = tempgroups.Max(p => p. TitleCount );
            var   modegroup  =tempgroups.Where(groups => groups.TitleCount == groupmax).Select(n =>  n.Title ).ToList();
            myNum =   modegroup.ToArray();
            var   medgroup  =listsort.Select(n =>  n.Title ).ToList();
            medarr = medgroup.ToArray();
            int size = medarr.Length;
            int mid = size/2;
            // int median = 0;
            if ((size % 2) != 0){
                calcmedian =  medarr[mid];
            }
            else {
                int val1 = medarr[mid - 1];
                int val2 = medarr[mid];
                int val3 = val1 + val2;
                calcmedian = Decimal.Divide(val3,2);
                calcmedian = Math.Round(calcmedian, 2);
            }
         }}
}