dotnet/maui · error · ArgumentNullException

targetProperty

Error message

targetProperty

What it means

Thrown by BindableObjectExtensions.SetBinding(this BindableObject, BindableProperty, string, ...) when targetProperty is null. This string-path extension builds a Binding and forwards to instance.SetBinding; the null guard prevents constructing a binding against an undefined target and matches the guard in the underlying SetBinding.

Source

Thrown at src/Controls/src/Core/BindableObjectExtensions.cs:67

			}
		}

		/// <summary>Creates and applies a binding to a property.</summary>
		/// <param name="self">The <see cref="Microsoft.Maui.Controls.BindableObject"/>.</param>
		/// <param name="targetProperty">The BindableProperty on which to set a binding.</param>
		/// <param name="path">A <see cref="System.String"/> indicating the property path to bind to.</param>
		/// <param name="mode">The <see cref="Microsoft.Maui.Controls.BindingMode"/> for the binding. This parameter is optional. Default is <see cref="Microsoft.Maui.Controls.BindingMode.Default"/>.</param>
		/// <param name="converter">An <see cref="Microsoft.Maui.Controls.IValueConverter"/> for the binding. This parameter is optional. Default is <see langword="null"/>.</param>
		/// <param name="stringFormat">A string used as stringFormat for the binding. This parameter is optional. Default is <see langword="null"/>.</param>
		/// <remarks>The following example shows how to use the extension method to set a binding.</remarks>
		[RequiresUnreferencedCode(TrimmerConstants.StringPathBindingWarning, Url = TrimmerConstants.ExpressionBasedBindingsDocsUrl)]
		public static void SetBinding(this BindableObject self, BindableProperty targetProperty, string path, BindingMode mode = BindingMode.Default, IValueConverter converter = null,
									  string stringFormat = null)
		{
			if (self == null)
				throw new ArgumentNullException(nameof(self));
			if (targetProperty == null)
				throw new ArgumentNullException(nameof(targetProperty));

			var binding = new Binding(path, mode, converter, stringFormat: stringFormat);
			self.SetBinding(targetProperty, binding);
		}

#nullable enable
		/// <summary>
		/// Creates a binding between a property on the source object and a property on the target object.
		/// </summary>
		/// <remarks>
		///   <para>The following example illustrates the setting of a binding using the extension method.</para>
		///   <example>
		///     <code lang="csharp lang-csharp"><![CDATA[
		///      public class PersonViewModel
		///      {
		///          public string Name { get; set; }
		///          public Address? Address { get; set; }
		///          // ...

View on GitHub (pinned to f377ff1c5e)

Solutions

1. Pass the correct static BindableProperty field for the target type.
2. Null-check targetProperty before calling when it is resolved dynamically.
3. Verify the BindableProperty field exists on the object type you are extending.

Example fix

// before
view.SetBinding(maybeNullProp, "Foo");
// after
if (maybeNullProp is not null)
    view.SetBinding(maybeNullProp, "Foo");

if (targetProperty is null) throw new InvalidOperationException("targetProperty not resolved");
self.SetBinding(targetProperty, path);

static bool CanBindStringPath(Microsoft.Maui.Controls.BindableObject o, Microsoft.Maui.Controls.BindableProperty p)
    => o is not null && p is not null;

When it happens

Trigger: Calling the string-path SetBinding with a null BindableProperty field; referencing a property field that was never initialized or was renamed; a property lookup helper returning null.

Common situations: Refactor that renamed a BindableProperty field; binding to a property declared on a different type; generic helpers resolving properties by name.

Related errors

• self
• binding
• application
• mainRenderer
• renderer

AI-assisted analysis of dotnet/maui@f377ff1c5e (2026-08-13). Data as JSON: /api/errors/fe50abe9cb386e97. Report an issue: GitHub.