Transparency type converter.

using System;

using System.ComponentModel;

 

namespace TypeEditorsCS

{

  /// <summary>

  /// Summary description for TransparencyConverter.

  /// </summary>

  public class TransparencyConverter : TypeConverter

  {

    public TransparencyConverter()

    {

    }

 

    public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType)

    {

      if(sourceType == typeof(string))

        return true;

      return base.CanConvertFrom (context, sourceType);

    }

 

    public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType)

    {

      if(destinationType == typeof(string))

        return true;

      return base.CanConvertTo (context, destinationType);

    }

 

    public override object ConvertFrom(ITypeDescriptorContext context, System.Globalization.CultureInfo culture, object value)

    {

      if(value is string)

      {

        string s=(string)value;

        int n=s.IndexOf("%");

        if(n>-1)

          s=s.Substring(0,n);

        try

        {

          int i=int.Parse(s);

          i=i>100 ? 100 : i<0 ? 0 : i;

          return 255-(i*255/100);

        }

        catch(Exception)

        {

          return 0;

        }

      }

      return base.ConvertFrom (context, culture, value);

    }

 

    public override object ConvertTo(ITypeDescriptorContext context, System.Globalization.CultureInfo culture, object value, Type destinationType)

    {

      if(destinationType==typeof(string))

      {

        return string.Format("{0}%",((255-(int)value)*100/255).ToString(""));

      }

      return base.ConvertTo (context, culture, value, destinationType);

    }

  }

}

Imports System

Imports System.ComponentModel

 

Public Class TransparencyConverter

  Inherits TypeConverter

  Public Sub New()

  End Sub

 

  Public Overloads Overrides Function CanConvertFrom(ByVal context As ITypeDescriptorContext, ByVal sourceType As Type) As Boolean

    If sourceType Is GetType(String) Then

      Return True

    End If

    Return MyBase.CanConvertFrom(context, sourceType)

  End Function

 

  Public Overloads Overrides Function CanConvertTo(ByVal context As ITypeDescriptorContext, ByVal destinationType As Type) As Boolean

    If destinationType Is GetType(String) Then

      Return True

    End If

    Return MyBase.CanConvertTo(context, destinationType)

  End Function

 

  Public Overloads Overrides Function ConvertFrom(ByVal context As ITypeDescriptorContext, ByVal culture As System.Globalization.CultureInfo, ByVal value As Object) As Object

    If TypeOf value Is String Then

      Dim s As String = CType(value, String)

      Dim n As Integer = s.IndexOf("%")

      If n > -1 Then

        s = s.Substring(0, n)

      End If

      Dim e As Exception

      Try

        Dim i As Integer = Integer.Parse(s)

        i = IIf(i > 100, 100, IIf(i < 0, 0, i))

        Return 255 - (i * 255 / 100)

      Catch e

        Return 0

      End Try

    End If

    Return MyBase.ConvertFrom(context, culture, value)

  End Function

 

  Public Overloads Overrides Function ConvertTo(ByVal context As ITypeDescriptorContext, ByVal culture As System.Globalization.CultureInfo, ByVal value As Object, ByVal destinationType As Type) As Object

    If destinationType Is GetType(String) Then

      Return String.Format("{0}%", ((255 - CInt(value)) * 100 / 255).ToString("0.00"))

    End If

    Return MyBase.ConvertTo(context, culture, value, destinationType)

  End Function

End Class