[iOS 26] - The MaxLength property value is not respected on an Entry control - fix #32045

kubaflo · 2025-10-17T14:13:27Z

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Description of Change

Introduces handling for the ShouldChangeCharactersInRanges event in EntryHandler for iOS 26.0 or greater, ensuring text changes respect max length constraints for multiple ranges. Event subscription and unsubscription are conditionally compiled for newer iOS versions.

https://developer.apple.com/documentation/uikit/uitextfielddelegate/textfield(_:shouldchangecharactersin:replacementstring:)

https://sebvidal.com/blog/whats-new-in-uikit-26/

Issues Fixed

Fixes #32016

Introduces handling for the ShouldChangeCharactersInRanges event in EntryHandler for iOS 26.0 or greater, ensuring text changes respect max length constraints for multiple ranges. Event subscription and unsubscription are conditionally compiled for newer iOS versions.

dotnet-policy-service · 2025-10-17T14:13:57Z

Hey there @@kubaflo! Thank you so much for your PR! Someone from the team will get assigned to your PR shortly and we'll get it reviewed.

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baaaaif · 2025-10-17T18:02:25Z

Wouldn't it be better to use a runtime check instead of a compile-time check?
Like done in this iOS 26 fix https://github.com/dotnet/maui/pull/31831/files

jfversluis · 2025-10-20T11:43:19Z

/azp run

azure-pipelines · 2025-10-20T11:43:39Z

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Pull Request Overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated 4 comments.

Copilot · 2025-10-20T11:44:27Z

src/Core/src/Handlers/Entry/EntryHandler.iOS.cs

+					return VirtualView?.TextWithinMaxLength(textField.Text, ranges[0].RangeValue, replacementString) ?? false;
+


Only the first range (ranges[0]) is evaluated; additional ranges are ignored, which can allow combined edits to exceed MaxLength or incorrectly deny valid input. Iterate all ranges to compute the prospective final text before enforcing MaxLength (e.g., build the resulting string by applying each range mutation) or extend VirtualView.TextWithinMaxLength to accept multiple ranges.

Suggested change

return VirtualView?.TextWithinMaxLength(textField.Text, ranges[0].RangeValue, replacementString) ?? false;

{

// Apply all ranges to the text to simulate the final result

string originalText = textField.Text ?? string.Empty;

var textChars = originalText.ToCharArray();

var resultText = originalText;

// If multiple ranges, apply them in order

// iOS passes the replacement string for all ranges, so we apply the replacement string to each range

// To avoid index shifting, process ranges in reverse order

var sortedRanges = ranges.Select(r => r.RangeValue).OrderByDescending(r => r.Location).ToArray();

foreach (var range in sortedRanges)

{

resultText = resultText.Remove((int)range.Location, (int)range.Length)

.Insert((int)range.Location, replacementString);

}

// Now check if the result is within max length

return VirtualView?.TextWithinMaxLength(resultText, new Foundation.NSRange(0, resultText.Length), string.Empty) ?? false;

}

Copilot · 2025-10-20T11:44:27Z

src/Core/src/Handlers/Entry/EntryHandler.iOS.cs

 			}

+#if IOS26_0_OR_GREATER
+			bool ShouldChangeCharactersInRanges(UITextField textField, NSValue[] ranges, string replacementString)


New multi-range input handling lacks associated UI and shared tests to validate MaxLength enforcement when multiple selections/ranges are modified (e.g., batch deletes or multi-cursor replacements). Please add a HostApp issue page exercising multiple-range edits and a corresponding TestCases.Shared.Tests UITest to ensure behavior matches expectations.

Copilot · 2025-10-20T11:44:27Z

src/Core/src/Handlers/Entry/EntryHandler.iOS.cs

+				if (ranges is { Length: > 0 })
+					return VirtualView?.TextWithinMaxLength(textField.Text, ranges[0].RangeValue, replacementString) ?? false;
+
+				return true;
+			}
+#else
 			bool OnShouldChangeCharacters(UITextField textField, NSRange range, string replacementString) =>
 				VirtualView?.TextWithinMaxLength(textField.Text, range, replacementString) ?? false;
+#endif



[nitpick] Two separate methods duplicate MaxLength enforcement logic with different parameter shapes. Consider extracting a shared helper that computes the prospective text (supporting single or multiple ranges) to reduce duplication and ensure consistent behavior across iOS versions.

Suggested change

if (ranges is { Length: > 0 })

return VirtualView?.TextWithinMaxLength(textField.Text, ranges[0].RangeValue, replacementString) ?? false;

return true;

}

#else

bool OnShouldChangeCharacters(UITextField textField, NSRange range, string replacementString) =>

VirtualView?.TextWithinMaxLength(textField.Text, range, replacementString) ?? false;

#endif

return IsTextWithinMaxLength(textField.Text, replacementString, ranges);

}

#else

bool OnShouldChangeCharacters(UITextField textField, NSRange range, string replacementString) =>

IsTextWithinMaxLength(textField.Text, replacementString, range);

#endif

/// <summary>

/// Helper to compute the prospective text after replacement and check MaxLength.

/// Supports both single and multiple ranges.

/// </summary>

bool IsTextWithinMaxLength(string currentText, string replacementString, params object[] ranges)

{

if (VirtualView == null)

return false;

string prospectiveText = currentText;

if (ranges.Length == 1 && ranges[0] is NSRange singleRange)

{

prospectiveText = ReplaceTextInRange(currentText, singleRange, replacementString);

}

else if (ranges.Length > 0 && ranges[0] is NSValue)

{

// Multiple ranges (iOS 16+)

foreach (var obj in ranges)

{

if (obj is NSValue val)

{

var range = val.RangeValue;

prospectiveText = ReplaceTextInRange(prospectiveText, range, replacementString);

}

}

}

return VirtualView.MaxLength <= 0 || prospectiveText.Length <= VirtualView.MaxLength;

}

/// <summary>

/// Helper to replace text in a given NSRange.

/// </summary>

string ReplaceTextInRange(string text, NSRange range, string replacement)

{

if (range.Location > text.Length)

return text;

int start = (int)range.Location;

int length = (int)range.Length;

if (start + length > text.Length)

length = text.Length - start;

return text.Substring(0, start) + replacement + text.Substring(start + length);

}

Copilot · 2025-10-20T11:44:28Z

src/Core/src/Handlers/Entry/EntryHandler.iOS.cs

+				if (ranges is { Length: > 0 })
+					return VirtualView?.TextWithinMaxLength(textField.Text, ranges[0].RangeValue, replacementString) ?? false;
+
+				return true;
+			}
+#else
 			bool OnShouldChangeCharacters(UITextField textField, NSRange range, string replacementString) =>
 				VirtualView?.TextWithinMaxLength(textField.Text, range, replacementString) ?? false;
+#endif



[nitpick] Two separate methods duplicate MaxLength enforcement logic with different parameter shapes. Consider extracting a shared helper that computes the prospective text (supporting single or multiple ranges) to reduce duplication and ensure consistent behavior across iOS versions.

Suggested change

if (ranges is { Length: > 0 })

return VirtualView?.TextWithinMaxLength(textField.Text, ranges[0].RangeValue, replacementString) ?? false;

return true;

}

#else

bool OnShouldChangeCharacters(UITextField textField, NSRange range, string replacementString) =>

VirtualView?.TextWithinMaxLength(textField.Text, range, replacementString) ?? false;

#endif

var prospectiveText = ComputeProspectiveText(textField.Text, ranges, replacementString);

return VirtualView?.TextWithinMaxLength(prospectiveText) ?? false;

}

#else

bool OnShouldChangeCharacters(UITextField textField, NSRange range, string replacementString)

{

var prospectiveText = ComputeProspectiveText(textField.Text, range, replacementString);

return VirtualView?.TextWithinMaxLength(prospectiveText) ?? false;

}

#endif

/// <summary>

/// Computes the prospective text after applying the replacement string to the given ranges.

/// </summary>

string ComputeProspectiveText(string currentText, NSValue[] ranges, string replacementString)

{

if (ranges == null || ranges.Length == 0)

return currentText;

// For iOS 26+, multiple ranges can be replaced at once.

var text = currentText;

foreach (var rangeValue in ranges)

{

var range = rangeValue.RangeValue;

text = text.Remove((int)range.Location, (int)range.Length)

.Insert((int)range.Location, replacementString);

}

return text;

}

/// <summary>

/// Computes the prospective text after applying the replacement string to the given range.

/// </summary>

string ComputeProspectiveText(string currentText, NSRange range, string replacementString)

{

if (range.Length == 0)

return currentText.Insert((int)range.Location, replacementString);

return currentText.Remove((int)range.Location, (int)range.Length)

.Insert((int)range.Location, replacementString);

}

Copilot AI review requested due to automatic review settings October 17, 2025 14:13

kubaflo changed the base branch from main to net10.0 October 17, 2025 14:13

dotnet-policy-service bot added the community ✨ Community Contribution label Oct 17, 2025

kubaflo changed the title ~~Fix 32016~~ [iOS 26] - The MaxLength property value is not respected on an Entry control - fix Oct 17, 2025

kubaflo self-assigned this Oct 17, 2025

kubaflo added the platform/ios label Oct 17, 2025

Copilot AI reviewed Oct 17, 2025

View reviewed changes

Update EntryHandler.iOS.cs

6157e44

jfversluis requested a review from Copilot October 20, 2025 11:43

Copilot AI reviewed Oct 20, 2025

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[iOS 26] - The MaxLength property value is not respected on an Entry control - fix #32045

[iOS 26] - The MaxLength property value is not respected on an Entry control - fix #32045

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		return VirtualView?.TextWithinMaxLength(textField.Text, ranges[0].RangeValue, replacementString) ?? false;

-					return VirtualView?.TextWithinMaxLength(textField.Text, ranges[0].RangeValue, replacementString) ?? false;
+				{
+					// Apply all ranges to the text to simulate the final result
+					string originalText = textField.Text ?? string.Empty;
+					var textChars = originalText.ToCharArray();
+					var resultText = originalText;
+					// If multiple ranges, apply them in order
+					// iOS passes the replacement string for all ranges, so we apply the replacement string to each range
+					// To avoid index shifting, process ranges in reverse order
+					var sortedRanges = ranges.Select(r => r.RangeValue).OrderByDescending(r => r.Location).ToArray();
+					foreach (var range in sortedRanges)
+					{
+						resultText = resultText.Remove((int)range.Location, (int)range.Length)
+							.Insert((int)range.Location, replacementString);
+					}
+					// Now check if the result is within max length
+					return VirtualView?.TextWithinMaxLength(resultText, new Foundation.NSRange(0, resultText.Length), string.Empty) ?? false;
+				}

-				if (ranges is { Length: > 0 })
-					return VirtualView?.TextWithinMaxLength(textField.Text, ranges[0].RangeValue, replacementString) ?? false;
-				return true;
-			}
-#else
-			bool OnShouldChangeCharacters(UITextField textField, NSRange range, string replacementString) =>
-				VirtualView?.TextWithinMaxLength(textField.Text, range, replacementString) ?? false;
-#endif
+				return IsTextWithinMaxLength(textField.Text, replacementString, ranges);
+			}
+#else
+			bool OnShouldChangeCharacters(UITextField textField, NSRange range, string replacementString) =>
+				IsTextWithinMaxLength(textField.Text, replacementString, range);
+#endif
+			/// <summary>
+			/// Helper to compute the prospective text after replacement and check MaxLength.
+			/// Supports both single and multiple ranges.
+			/// </summary>
+			bool IsTextWithinMaxLength(string currentText, string replacementString, params object[] ranges)
+			{
+				if (VirtualView == null)
+					return false;
+				string prospectiveText = currentText;
+				if (ranges.Length == 1 && ranges[0] is NSRange singleRange)
+				{
+					prospectiveText = ReplaceTextInRange(currentText, singleRange, replacementString);
+				}
+				else if (ranges.Length > 0 && ranges[0] is NSValue)
+				{
+					// Multiple ranges (iOS 16+)
+					foreach (var obj in ranges)
+					{
+						if (obj is NSValue val)
+						{
+							var range = val.RangeValue;
+							prospectiveText = ReplaceTextInRange(prospectiveText, range, replacementString);
+						}
+					}
+				}
+				return VirtualView.MaxLength <= 0 || prospectiveText.Length <= VirtualView.MaxLength;
+			}
+			/// <summary>
+			/// Helper to replace text in a given NSRange.
+			/// </summary>
+			string ReplaceTextInRange(string text, NSRange range, string replacement)
+			{
+				if (range.Location > text.Length)
+					return text;
+				int start = (int)range.Location;
+				int length = (int)range.Length;
+				if (start + length > text.Length)
+					length = text.Length - start;
+				return text.Substring(0, start) + replacement + text.Substring(start + length);
+			}

-				if (ranges is { Length: > 0 })
-					return VirtualView?.TextWithinMaxLength(textField.Text, ranges[0].RangeValue, replacementString) ?? false;
-				return true;
-			}
-#else
-			bool OnShouldChangeCharacters(UITextField textField, NSRange range, string replacementString) =>
-				VirtualView?.TextWithinMaxLength(textField.Text, range, replacementString) ?? false;
-#endif
+				var prospectiveText = ComputeProspectiveText(textField.Text, ranges, replacementString);
+				return VirtualView?.TextWithinMaxLength(prospectiveText) ?? false;
+			}
+#else
+			bool OnShouldChangeCharacters(UITextField textField, NSRange range, string replacementString)
+			{
+				var prospectiveText = ComputeProspectiveText(textField.Text, range, replacementString);
+				return VirtualView?.TextWithinMaxLength(prospectiveText) ?? false;
+			}
+#endif
+			/// <summary>
+			/// Computes the prospective text after applying the replacement string to the given ranges.
+			/// </summary>
+			string ComputeProspectiveText(string currentText, NSValue[] ranges, string replacementString)
+			{
+				if (ranges == null || ranges.Length == 0)
+					return currentText;
+				// For iOS 26+, multiple ranges can be replaced at once.
+				var text = currentText;
+				foreach (var rangeValue in ranges)
+				{
+					var range = rangeValue.RangeValue;
+					text = text.Remove((int)range.Location, (int)range.Length)
+						.Insert((int)range.Location, replacementString);
+				}
+				return text;
+			}
+			/// <summary>
+			/// Computes the prospective text after applying the replacement string to the given range.
+			/// </summary>
+			string ComputeProspectiveText(string currentText, NSRange range, string replacementString)
+			{
+				if (range.Length == 0)
+					return currentText.Insert((int)range.Location, replacementString);
+				return currentText.Remove((int)range.Location, (int)range.Length)
+					.Insert((int)range.Location, replacementString);
+			}

[iOS 26] - The MaxLength property value is not respected on an Entry control - fix #32045

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[iOS 26] - The MaxLength property value is not respected on an Entry control - fix #32045

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kubaflo commented Oct 17, 2025 •

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