PRB: "Invalid property value" Error Message While Setting Values for User Control Properties in Design View When Using Visual Studio .NET (818811)

SYMPTOMS

If you try to set the value of the BrowsableAttribute property to TRUE during design time in Microsoft Visual Studio .NET, and if the control class has certain types of properties, you receive the following error message:

Invalid property value

The following are the types of control class properties that this situation applies to:

PointF
SizeF
RectangleF

CAUSE

This problem occurs because predefined type converter classes are not available for the structures that are listed in "Symptoms". The default converters for the classes are as follows:

	Class	Default Converter
	Point	PointConverter
	Size	SizeConverter
	Rectangle	RectangleConverter

Note You cannot use these default converters as the type converters for PointF, SizeF and RectangleF.

WORKAROUND

To work around this problem, use one of the following methods:

Use different types for the properties that are to be exposed by the control:

	Instead of this property:	Use this property:
	PointF	Point
	SizeF	Size
	RectangleF	Rectangle

- or -

Use type converters for PointF, SizeF and RectangleF.

For more information about how to write type converters, see the "References" section of this article.

MORE INFORMATION

Steps to Reproduce the Behavior

Create a Microsoft Visual C# Windows Control Library in Visual Studio .NET.

Add the following code to the code that the wizard generated for the user control class:

private PointF m_Point;

[Browsable(true)]
[TypeConverter("System.Drawing.PointConverter, System.Drawing")]
public PointF Position
{
	get
	{
		return m_Point;
	}
	set
	{
		m_Point = value;
	}
}

Build the application.
Create a Visual C# Windows application in Visual Studio .NET.
Right-click Windows Forms Toolbox, and then click Customize Toolbox.
In the Customize Toolbox dialog box, select the .NET Framework Components check box, and then click Browse.
In the Open dialog box, specify the path of the dynamic link library (DLL) that you created for the Windows Control Library (steps 1 to 3), and then click Open.
Click OK to close the Customize Toolbox dialog box.
Drag the user control from the Windows Forms Toolbox onto the design view.
Right-click the control on the design view, and then click Properties.
Scroll to the Position property that is under the Misc section.

If you modify the value of this property, you receive the error that is mentioned in the "Symptoms" section.

REFERENCES

For additional information about implementing a type converter, see the following MSDN documentation:

Implementing a Type Converter
http://msdn.microsoft.com/library/en-us/cpguide/html/cpconimplementingtypeconverter.asp

For additional information about design time support that is available in Visual Studio .NET, see the following MSDN documentation:

Enhancing Design-Time Support
http://msdn.microsoft.com/library/en-us/cpguide/html/cpconenhancingdesign-timesupport.asp