dotnet/maui · error · InvalidOperationException

MinimumDate must be lower than MaximumDate

Error message

MinimumDate must be lower than MaximumDate

What it means

The GTK DatePicker control's MinimumDate setter validates that the new MinimumDate is not above the existing MaximumDate (condition `MaximumDate < value`). Setting MinimumDate above the current MaximumDate throws InvalidOperationException. The check uses the live MaximumDate property, so order of setting matters.

Source

Thrown at src/Compatibility/Core/src/GTK/Controls/DatePicker.cs:186

			public RangeCalendar()
			{
				_minimumDate = new DateTime(1900, 1, 1);
				_maximumDate = new DateTime(2199, 1, 1);
			}

			public DateTime MinimumDate
			{
				get
				{
					return _minimumDate;
				}

				set
				{
					if (MaximumDate < value)
					{
						throw new InvalidOperationException($"{nameof(MinimumDate)} must be lower than {nameof(MaximumDate)}");
					}

					_minimumDate = value;
				}
			}

			public DateTime MaximumDate
			{
				get
				{
					return _maximumDate;
				}

				set
				{
					if (MinimumDate > value)
					{
						throw new InvalidOperationException($"{nameof(MaximumDate)} must be greater than {nameof(MinimumDate)}");

View on GitHub (pinned to f377ff1c5e)

Solutions

1. Set MaximumDate first (or widen it) before raising MinimumDate, or lower MinimumDate before lowering MaximumDate to keep the invariant min <= max.
2. Validate the incoming value against the current MaximumDate before assignment.
3. Clamp the value rather than throwing if the source is untrusted.

Example fix

// before — min above existing max
picker.MaximumDate = DateTime.Today;
picker.MinimumDate = DateTime.Today.AddDays(30); // throws
// after — raise the max first
picker.MaximumDate = DateTime.Today.AddDays(60);
picker.MinimumDate = DateTime.Today.AddDays(30);

static void SafeSetMinimum(DateTimePicker picker, DateTime value)
{
    if (value > picker.MaximumDate) picker.MaximumDate = value;
    picker.MinimumDate = value;
}

try { picker.MinimumDate = newMin; }
catch (InvalidOperationException) { picker.MaximumDate = newMin; picker.MinimumDate = newMin; }

When it happens

Trigger: Assigning MinimumDate to a value greater than the current MaximumDate — e.g. MaximumDate is DateTime.Today and you set MinimumDate to a week from now.

Common situations: Initializing DatePicker bounds from data where the min ends up above the max; setting MinimumDate before raising MaximumDate; binding both from a source where they cross.

Related errors

• MaximumDate must be greater than MinimumDate
• OpenGL dll not found!
• Glx entry point not found!
• call Forms.Init() before this
• call GtkThemes.Init() before this

AI-assisted analysis of dotnet/maui@f377ff1c5e (2026-08-13). Data as JSON: /api/errors/4e32af39ffbd301a. Report an issue: GitHub.