Preventing Registry.GetValue overflow

Question

I'm trying to get the DWM colorizationColor using: Microsoft.Win32.Registry.CurrentUser.OpenSubKey(@"Software\Microsoft\Windows\DWM").GetValue("ColorizationColor")

however it is returning -2144154163 (the real value is 2150813133)

I thinks this is because the value cannot be hold on a 32-bit int... however event casting (or Converting) to int64 fails.

PD: It may sound like an easy question to answer but I cannot find a solution :(

score 3 · Accepted Answer · answered Nov 14 '10 at 15:25

3

Color values are pretty impractical as int values, it is best to convert it quickly. A little wrapper to dispose the key doesn't hurt either:

using System.Drawing;
...
        public static Color GetDwmColorizationColor() {
            using (var key = Microsoft.Win32.Registry.CurrentUser.OpenSubKey(@"Software\Microsoft\Windows\DWM")) {
                return Color.FromArgb((int)key.GetValue("ColorizationColor"));
            }
        }

But don't do it this way, there's a documented API for it. P/Invoke DwmGetColorizationColor() to get the value, you'll get guaranteed compatibility behavior. Important if some future Windows version changes this registry details. Visit pinvoke.net for the declaration.

answered Nov 14 '10 at 15:25

Hans Passant

922,412
146
1,693
2,536

wow, it is exactly but i was looking for, thanks for the advice anyway, however is was using this because of http://www.withinwindows.com/2010/07/01/retrieving-aero-glass-base-color-for-opaque-surface-rendering/ the value can change depending whether transpareceny is enabled or not – David Fernández Nov 14 '10 at 15:32
See http://stackoverflow.com/questions/3560890/vista-7-how-to-get-glass-color for detailed examples showing `DwmGetColorizationColor` doesn't work as advertised. – Ian Boyd Jan 18 '11 at 18:04

score 2 · Answer 2 · edited Jul 23 '22 at 11:01

2

You need to make an unchecked cast:

unchecked {
    value = (uint)intValue;
}

EDIT: Registry.GetValue returns an object containing a boxed Int32 value.
You cannot unbox the value and cast to a different value type in a single cast.

When casting directly from object, you need to first unbox it to its actual type, then cast it to uint:

unchecked {
    value = (uint)(int)boxedObject;
}

edited Jul 23 '22 at 11:01

Glorfindel

21,988
13
81
109

answered Nov 14 '10 at 15:09

SLaks

868,454
176
1,908
1,964

@Luffy: See my edit, and see http://blogs.msdn.com/b/ericlippert/archive/2009/03/19/representation-and-identity.aspx – SLaks Nov 14 '10 at 15:20

Preventing Registry.GetValue overflow

2 Answers2