C# Signature:
[DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]
static extern IntPtr LoadImage(IntPtr hinst, string lpszName, uint uType,
int cxDesired, int cyDesired, uint fuLoad);
VB Signature:
<DllImport("user32.dll", SetLastError:=True)> _
Private Shared Function LoadImage(ByVal hInst As IntPtr, ByVal lpszName As String, ByVal uType As UInt32, _
ByVal cxDesired As Integer, ByVal cyDesired As Integer, ByVal fuLoad As UInt32) As IntPtr
End Function
C++/CLI Signature:
[DllImportAttribute("user32.dll", SetLastError = true, CharSet = CharSet::Auto)]
extern "C" int LoadImage(int hinst, int lpszName, unsigned int uType, int cxDesired, int cyDesired, unsigned int fuLoad);
User-Defined Types:
None.
User-Defined Constants:
Notes:
C++/CLI: This solution allows you to load an image from an unmanaged resource in the assembly. In my case I added a .cur file to my .rc. The cursor had an ID of 101. After loading the cursor I assigned it to the Forms::Cursor.
Tips & Tricks:
To use integer resource ID instead of string, and avoid using MAKEINTRESOURCE, prepend the integer with '#'. For example, to use resource ID 32512, enter "#32512" for lpszName.
To load application icons of different sizes, use cxDesired and cyDesired (see the example).
Sample Code:
C++/CLI Example
using namespace System::Runtime::InteropServices;
using namespace System::Windows::Forms;
using namespace System::Reflection;
int a = LoadImage(Marshal::GetHINSTANCE(Assembly::GetExecutingAssembly()->GetModules()[0]).ToInt32(),101,2,0,0,0);
this->Cursor = gcnew ::Cursor(IntPtr(a));
Sample Code (C#):
namespace ITLN.Utils.GUI {
// http://www.itln.pl
public static class AuxiliaryGUIIcon {
[DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]
private static extern IntPtr LoadImage(IntPtr hinst, string lpszName, uint uType,
int cxDesired, int cyDesired, uint fuLoad);
[DllImport("user32.dll", SetLastError = true)]
private static extern int DestroyIcon(IntPtr hIcon);
[DllImport("kernel32.dll", SetLastError = true, CharSet = CharSet.Auto)]
private static extern IntPtr LoadLibraryEx(string lpFileName, IntPtr hFile, LoadLibraryFlags dwFlags);
private enum LoadLibraryFlags : uint {
DONT_RESOLVE_DLL_REFERENCES = 0x00000001,
LOAD_IGNORE_CODE_AUTHZ_LEVEL = 0x00000010,
LOAD_LIBRARY_AS_DATAFILE = 0x00000002,
LOAD_LIBRARY_AS_DATAFILE_EXCLUSIVE = 0x00000040,
LOAD_LIBRARY_AS_IMAGE_RESOURCE = 0x00000020,
LOAD_WITH_ALTERED_SEARCH_PATH = 0x00000008
}
/// <summary>
/// Returns an icon of given size.
/// </summary>
/// <param name="path">Path to a file (.exe/.dll) that contains the icons.
/// Skip it or use <c>null</c> to use current application's file.</param>
/// <param name="resId">Name of the resource icon that should be loaded.
/// Skip it to use the default <c>#32512</c> (value of <c>IDI_APPLICATION</c>) to use
/// the application's icon.</param>
/// <param name="size">Size of the icon to load. If there is no such size available, a larger or smaller
/// sized-icon is scaled.</param>
/// <returns>List of all icons.</returns>
public static Icon GetIconFromExe(string path = null, string resId = "#32512", int size = 32) {
// load module
IntPtr h;
if (path == null)
h = Marshal.GetHINSTANCE(Assembly.GetEntryAssembly().GetModules()[0]);
else {
h = LoadLibraryEx(path, IntPtr.Zero, LoadLibraryFlags.LOAD_LIBRARY_AS_DATAFILE);
if (h == IntPtr.Zero)
return null;
}
// 1 is IMAGE_ICON
IntPtr ptr = LoadImage(h, resId, 1, size, size, 0);
if (ptr != IntPtr.Zero) {
try {
Icon icon = (Icon)Icon.FromHandle(ptr).Clone();
return icon;
} finally {
DestroyIcon(ptr);
}
}
return null;
}
}
}
Alternative Managed API:
- or to load an image from a managed resource (dll):
System.Drawing.Bitmap.FromResource
