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@mlasson
Created May 24, 2018 16:54
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Pinning to the taskbar a “chained process”
using System;
using System.Windows.Forms;
using System.Runtime.InteropServices;
using System.Runtime.CompilerServices;
/* Source: https://stackoverflow.com/questions/48539789/pinning-to-the-taskbar-a-chained-process */
internal struct PropertyKey
{
Guid formatId;
int propertyId;
internal PropertyKey(Guid guid, int propertyId)
{
this.formatId = guid;
this.propertyId = propertyId;
}
}
[StructLayout(LayoutKind.Explicit)]
internal struct PropVariant
{
[FieldOffset(0)] internal ushort vt;
[FieldOffset(8)] internal IntPtr pv;
[FieldOffset(8)] internal UInt64 padding;
[DllImport("Ole32.dll", PreserveSig = false)]
internal static extern void PropVariantClear(ref PropVariant pvar);
internal PropVariant(string value)
{
this.vt = (ushort)VarEnum.VT_LPWSTR;
this.padding = 0;
this.pv = Marshal.StringToCoTaskMemUni(value);
}
internal void Clear()
{
PropVariantClear (ref this);
}
}
[ComImport,
Guid("886D8EEB-8CF2-4446-8D02-CDBA1DBDCF99"),
InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
interface IPropertyStore
{
int GetCount([Out] out uint propertyCount);
void GetAt([In] uint propertyIndex, [Out, MarshalAs(UnmanagedType.Struct)] out PropertyKey key);
void GetValue([In, MarshalAs(UnmanagedType.Struct)] ref PropertyKey key, [Out, MarshalAs(UnmanagedType.Struct)] out PropVariant pv);
void SetValue([In, MarshalAs(UnmanagedType.Struct)] ref PropertyKey key, [In, MarshalAs(UnmanagedType.Struct)] ref PropVariant pv);
void Commit();
}
internal static class TaskBar {
[DllImport("shell32.dll")]
static extern int SHGetPropertyStoreForWindow(
IntPtr hwnd,
ref Guid iid /*IID_IPropertyStore*/,
[Out(), MarshalAs(UnmanagedType.Interface)]out IPropertyStore propertyStore);
internal static class Key {
private static Guid propGuid = new Guid("9F4C2855-9F79-4B39-A8D0-E1D42DE1D5F3");
internal static PropertyKey AppId = new PropertyKey(propGuid, 5);
internal static PropertyKey RelaunchCommand = new PropertyKey(propGuid, 2);
internal static PropertyKey DisplayName = new PropertyKey(propGuid, 4);
}
private static void ClearValue(IPropertyStore store, PropertyKey key) {
var prop = new PropVariant();
prop.vt = (ushort)VarEnum.VT_EMPTY;
store.SetValue(ref key, ref prop);
}
private static void SetValue(IPropertyStore store, PropertyKey key, string value) {
var prop = new PropVariant(value);
store.SetValue(ref key, ref prop);
prop.Clear();
}
internal static IPropertyStore Store(IntPtr handle) {
IPropertyStore store;
var store_guid = new Guid("886D8EEB-8CF2-4446-8D02-CDBA1DBDCF99");
int rc = SHGetPropertyStoreForWindow(handle, ref store_guid, out store);
if (rc != 0) throw Marshal.GetExceptionForHR(rc);
return store;
}
internal static void SetupLauncher(Form form) {
IntPtr handle = form.Handle;
var store = Store(handle);
SetValue (store, Key.AppId, "Stackoverflow.chain.process.pinning");
form.FormClosed += delegate { Cleanup(handle); };
}
internal static void SetupLaunchee(Form form) {
IntPtr handle = form.Handle;
var store = Store(handle);
SetValue (store, Key.AppId, "Stackoverflow.chain.process.pinning");
string exePath = System.IO.Path.Combine(System.Windows.Forms.Application.StartupPath, "launcher.exe");
SetValue (store, Key.RelaunchCommand, exePath);
SetValue (store, Key.DisplayName, "Test");
form.FormClosed += delegate { Cleanup(handle); };
}
internal static void Cleanup(IntPtr handle) {
var store = Store(handle);
ClearValue (store, Key.AppId);
ClearValue (store, Key.RelaunchCommand);
ClearValue (store, Key.DisplayName);
}
}
@mlasson
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mlasson commented Dec 5, 2023

Thanks for this feedback !
This problem is no longer a problem I need to solve but it may be helpful to someone else.

@marbel82
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marbel82 commented Dec 5, 2023

Do you remember why you are doing:

  form.FormClosed += delegate { Cleanup(handle); };

Is it needed? Why should we clean it as the window is closed?

@mlasson
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mlasson commented Dec 6, 2023

No idea ! I would not be surprised if this is just a zealous and unnecessary cleanup.

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