Is it possible to mark a property shown in a property grid as a password field

Starting with .Net 2, you can use the PasswordPropertyTextAttribute attached to your password property.

Hope this helps.

Here's what I've done in the past. It displays "********" for the password in the grid, with a "..." button to allow the user to set the password (using a dialog that you supply).

public class User
{
    [TypeConverter(typeof(PasswordConverter))]
    [Editor(typeof(PasswordEditor), typeof(UITypeEditor))]
    public string Password { get; set; }
}

public class PasswordConverter : TypeConverter
{
    public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType)
    {
        if (destinationType == typeof(string)) return true;

        return base.CanConvertTo(context, destinationType);
    }

    public override object ConvertTo(ITypeDescriptorContext context, System.Globalization.CultureInfo culture, object value, Type destinationType)
    {
        if (destinationType == typeof(string))
        {
            string password = (string)value;

            if (password != null && password.Length > 0)
            {
                return "********";
            }
        }

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

public class PasswordEditor : UITypeEditor
{
    public override object EditValue(ITypeDescriptorContext context, IServiceProvider provider, object value)
    {
        string password = (string)value;

        // Show a dialog allowing the user to enter a password

        return password;
    }

    public override UITypeEditorEditStyle GetEditStyle(ITypeDescriptorContext context)
    {
        return UITypeEditorEditStyle.Modal;
    }
}