TextBox: Data-type validation for max chars (fixes #18817) (#20843)

* configure max chars for textbox

* min 1

* Adds server-side check for text box min and max character validation.

* Applied suggestion from code review.

* Bumped version of test helper

* Fixed test that was creating a text string data type with too large a maximum characters setting.

---------

Co-authored-by: Andy Butland <abutland73@gmail.com>
Co-authored-by: Nhu Dinh <hnd@umbraco.dk>

src/Umbraco.Core/PropertyEditors/TextboxConfigurationEditor.cs

@@ -1,7 +1,8 @@
-// Copyright (c) Umbraco.
+// Copyright (c) Umbraco.
 // See LICENSE for more details.
 
 using Umbraco.Cms.Core.IO;
+using Umbraco.Cms.Core.PropertyEditors.Validators;
 
 namespace Umbraco.Cms.Core.PropertyEditors;
 
@@ -10,8 +11,17 @@ namespace Umbraco.Cms.Core.PropertyEditors;
 /// </summary>
 public class TextboxConfigurationEditor : ConfigurationEditor<TextboxConfiguration>
 {
+    /// <summary>
+    /// Initializes a new instance of the <see cref="TextboxConfigurationEditor"/> class.
+    /// </summary>
     public TextboxConfigurationEditor(IIOHelper ioHelper)
         : base(ioHelper)
     {
+        const int MinChars = 1;
+        const int MaxChars = 512;
+        Fields.Add(new ConfigurationField(new IntegerValidator(MinChars, MaxChars))
+        {
+            Key = "maxChars",
+        });
     }
 }

src/Umbraco.Core/PropertyEditors/Validators/IntegerValidator.cs

@@ -5,19 +5,52 @@ using Umbraco.Extensions;
 namespace Umbraco.Cms.Core.PropertyEditors.Validators;
 
 /// <summary>
-///     A validator that validates that the value is a valid integer
+///     A validator that validates that the value is a valid integer.
 /// </summary>
 public sealed class IntegerValidator : IValueValidator
 {
+    private readonly int? _minValue;
+    private readonly int? _maxValue;
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="IntegerValidator"/> class.
+    /// </summary>
+    public IntegerValidator()
+    {
+    }
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="IntegerValidator"/> class with minimum and/or maximum values.
+    /// </summary>
+    public IntegerValidator(int? minValue, int? maxValue)
+    {
+        _minValue = minValue;
+        _maxValue = maxValue;
+    }
+
     /// <inheritdoc />
     public IEnumerable<ValidationResult> Validate(object? value, string? valueType, object? dataTypeConfiguration, PropertyValidationContext validationContext)
     {
-        if (value != null && value.ToString() != string.Empty)
+        if (value == null || value.ToString() == string.Empty)
         {
-            Attempt<int> result = value.TryConvertTo<int>();
-            if (result.Success == false)
+            yield break;
+        }
+
+        Attempt<int> result = value.TryConvertTo<int>();
+        if (result.Success == false)
+        {
+            yield return new ValidationResult("The value " + value + " is not a valid integer", ["value"]);
+        }
+        else
+        {
+            if (_minValue.HasValue && result.Result < _minValue.Value)
             {
-                yield return new ValidationResult("The value " + value + " is not a valid integer", new[] { "value" });
+                yield return new ValidationResult("The value " + value + " is less than the minimum allowed value of " + _minValue.Value, ["value"]);
+            }
+
+            if (_maxValue.HasValue && result.Result > _maxValue.Value)
+            {
+                yield return new ValidationResult("The value " + value + " is greater than the maximum allowed value of " + _maxValue.Value, ["value"]);
             }
         }
     }