ExpandableObjectConverter Class

Definition

Provides a type converter to convert expandable objects to and from various other representations.

public class ExpandableObjectConverter : System.ComponentModel.TypeConverter
Inheritance
ExpandableObjectConverter
Derived

Inherited Members

System.ComponentModel.TypeConverter

System.Object

Examples

The following code example converts a variable of type Margins to a string variable.

String^ strM = "1,2,3,4";
System::Drawing::Printing::Margins^ m = gcnew System::Drawing::Printing::Margins( 1,2,3,4 );
Console::WriteLine( TypeDescriptor::GetConverter( strM )->CanConvertTo( System::Drawing::Printing::Margins::typeid ) );
Console::WriteLine( TypeDescriptor::GetConverter( m )->ConvertToString( m ) );
string strM="1,2,3,4";
System.Drawing.Printing.Margins  m= new System.Drawing.Printing.Margins(1,2,3,4);
Console.WriteLine(TypeDescriptor.GetConverter(strM).CanConvertTo(typeof(System.Drawing.Printing.Margins))); 
Console.WriteLine(TypeDescriptor.GetConverter(m).ConvertToString(m)); 
Dim strM As String
strM = "1,2,3,4"
            Dim m As New System.Drawing.Printing.Margins(1, 2, 3, 4)
Console.WriteLine(TypeDescriptor.GetConverter(strM).CanConvertTo(GetType(System.Drawing.Printing.Margins)))
Console.WriteLine(TypeDescriptor.GetConverter(m).ConvertToString(m))

The following code example demonstrates how to use the NotifyParentPropertyAttribute and the ExpandableObjectConverter class to create an expandable property on a custom control. This code example is part of a larger example provided for the NotifyParentPropertyAttribute class.

[TypeConverter(typeof(BorderAppearanceConverter))]
public class BorderAppearance
{
    private int borderSizeValue = 1;
    private Color borderColorValue = Color.Empty;

    [Browsable(true),
    NotifyParentProperty(true),
    EditorBrowsable(EditorBrowsableState.Always),
    DefaultValue(1)]
    public int BorderSize
    {
        get
        {
            return borderSizeValue;
        }
        set
        {
            if (value < 0)
            {
                throw new ArgumentOutOfRangeException(
                    "BorderSize",
                    value,
                    "must be >= 0");
            }

            if (borderSizeValue != value)
            {
                borderSizeValue = value;
            }
        }
    }

    [Browsable(true)]
    [NotifyParentProperty(true)]
    [EditorBrowsable(EditorBrowsableState.Always)]
    [DefaultValue(typeof(Color), "")]
    public Color BorderColor
    {
        get
        {
            return borderColorValue;
        }
        set
        {
            if (value.Equals(Color.Transparent))
            {
                throw new NotSupportedException("Transparent colors are not supported.");
            }

            if (borderColorValue != value)
            {
                borderColorValue = value;
            }
        }
    }
}
<TypeConverter(GetType(BorderAppearanceConverter))>  _
Public Class BorderAppearance
    Private borderSizeValue As Integer = 1
    Private borderColorValue As Color = Color.Empty
    
    
    <Browsable(True), NotifyParentProperty(True), EditorBrowsable(EditorBrowsableState.Always), DefaultValue(1)>  _
    Public Property BorderSize() As Integer 
        Get
            Return borderSizeValue
        End Get
        Set
            If value < 0 Then
                Throw New ArgumentOutOfRangeException("BorderSize", value, "must be >= 0")
            End If
            
            If borderSizeValue <> value Then
                borderSizeValue = value
            End If
        End Set
    End Property
    
    
    <Browsable(True), NotifyParentProperty(True), EditorBrowsable(EditorBrowsableState.Always), DefaultValue(GetType(Color), "")>  _
    Public Property BorderColor() As Color 
        Get
            Return borderColorValue
        End Get
        Set
            If value.Equals(Color.Transparent) Then
                Throw New NotSupportedException("Transparent colors are not supported.")
            End If
            
            If borderColorValue <> value Then
                borderColorValue = value
            End If
        End Set
    End Property
End Class

Remarks

This class adds support for properties on an object to the methods and properties provided by TypeConverter. To make a type of property expandable in the PropertyGrid, specify this TypeConverter for standard implementations of GetPropertiesSupported and GetProperties. Mark child properties with the NotifyParentPropertyAttribute to ensure correct behavior in a PropertyGrid control.

Note

You should never access a type converter directly. Instead, call the appropriate converter by using TypeDescriptor. For more information, see the examples in the TypeConverter base class.

For more information about type converters, see the TypeConverter base class and How to: Implement a Type Converter.

Constructors

ExpandableObjectConverter()

Initializes a new instance of the ExpandableObjectConverter class.

Methods

GetProperties(ITypeDescriptorContext, Object, Attribute[])

Gets a collection of properties for the type of object specified by the value parameter.

GetPropertiesSupported(ITypeDescriptorContext)

Gets a value indicating whether this object supports properties using the specified context.