InsertMenuItem cutting off the string to first char

I am trying to modify window's system menu using InsertMenuItem (instead of InsertMenu - the reason is that I want to insert submenus eventually). Language is C#.

Tried inserting a new item, tried getting existing item and reinserting it, it inserts, but the item string is shown in the menu only as the first character. Anyone have a clue about what I am missing?

// try creating one from scratch
MENUITEMINFO it = new MENUITEMINFO();
it.cbSize = (uint)Marshal.SizeOf(it);
it.fMask = 64;// MIIM_STRING
it.wID = 12345;
it.dwTypeData = "Now is the time";
it.fType = 0;
it.cch = 0;
InsertMenuItem(hSysMenu, 7, true, ref it);

//try copying one
GetMenuItemInfo(hSysMenu, (uint)0, true, ref it);
it.cch += 10;
it.dwTypeData = new string(' ', (int)(menuItemInfo.cch+10));
GetMenuItemInfo(hSysMenu, (uint)0, true, ref it);
it.wID = 123456;
var err = InsertMenuItem(hSysMenu, 1, true, ref it);


The result of the above code

1 Answer
1

Ok I finally figured it out. I will leave this here so maybe someone else later will find it when they are baffled by this.

The reason was that the InsertMenuItem p/invoke was defined with

[DllImport("user32.dll")] in the pinvoke.net site - see https://www.pinvoke.net/default.aspx/user32/insertmenu.html?diff=y

and it needs to be

[DllImport("user32.dll", CharSet = CharSet.Auto) ]

I changed the pinvoke.net page to reflect it.

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