我正在为 Windows 资源管理器实现一个 shell 上下文菜单,并成功创建了菜单。我遇到的问题是 IContextMenu::GetCommandString 方法,当您将鼠标悬停在所选菜单项上时,该方法会在状态栏中显示帮助文本。
当我将鼠标悬停在每个项目上时,什么都没有显示,但奇怪的是我没有创建的其他一些项目,例如 - 打开或打印,它们的帮助文本变成了垃圾。
这是 IContextMenu::QueryContextMenu & IContextMenu::GetCommandString 的代码示例。
int ShellExtLib.IContextMenu.QueryContextMenu(IntPtr hMenu, uint indexMenu, uint idCmdFirst, uint idCmdLast, uint uFlags)
{
uint idCmd = idCmdFirst;
StringBuilder sb = new StringBuilder(1024);
try
{
if ((uFlags & 0xf) == 0 || (uFlags & (uint)ShellExtLib.CMF.CMF_EXPLORE) != 0)
{
uint selectedFileCount = Helpers.DragQueryFile(m_hDrop, 0xffffffff, null, 0);
if (selectedFileCount == 1)
{
Helpers.DragQueryFile(m_hDrop, 0, sb, sb.Capacity + 1);
Documents.Add(sb.ToString());
}
else
{
// MULTIPLE FILES SELECTED.
for (uint i = 0; i < selectedFileCount; i++)
{
Helpers.DragQueryFile(m_hDrop, i, sb, sb.Capacity + 1);
Documents.Add(sb.ToString());
}
}
Helpers.InsertMenu(hMenu, indexMenu++, ShellExtLib.UFLAGS.MF_SEPARATOR | ShellExtLib.UFLAGS.MF_BYPOSITION, 0, null);
IntPtr hSubMenu = Helpers.CreateMenu();
if (hSubMenu != IntPtr.Zero)
{
Helpers.InsertMenu(hSubMenu, 0, ShellExtLib.UFLAGS.MF_STRING | ShellExtLib.UFLAGS.MF_BYPOSITION, idCmd++, "Item 1");
Helpers.InsertMenu(hSubMenu, 1, ShellExtLib.UFLAGS.MF_STRING | ShellExtLib.UFLAGS.MF_BYPOSITION, idCmd++, "Item 2");
Helpers.InsertMenu(hSubMenu, 2, ShellExtLib.UFLAGS.MF_SEPARATOR | ShellExtLib.UFLAGS.MF_BYPOSITION, idCmd++, null);
Helpers.InsertMenu(hSubMenu, 3, ShellExtLib.UFLAGS.MF_STRING | ShellExtLib.UFLAGS.MF_BYPOSITION, idCmd++, "Item 3");
Helpers.InsertMenu(hSubMenu, 4, ShellExtLib.UFLAGS.MF_SEPARATOR | ShellExtLib.UFLAGS.MF_BYPOSITION, idCmd++, null);
Helpers.InsertMenu(hSubMenu, 5, ShellExtLib.UFLAGS.MF_STRING | ShellExtLib.UFLAGS.MF_BYPOSITION, idCmd++, "Item 4");
Helpers.InsertMenu(hSubMenu, 6, ShellExtLib.UFLAGS.MF_STRING | ShellExtLib.UFLAGS.MF_BYPOSITION, idCmd++, "Item 5");
}
Helpers.InsertMenu(hMenu, indexMenu++, ShellExtLib.UFLAGS.MF_STRING | ShellExtLib.UFLAGS.MF_BYPOSITION | ShellExtLib.UFLAGS.MF_POPUP, (uint)hSubMenu, "Main Menu");
Helpers.InsertMenu(hMenu, indexMenu++, ShellExtLib.UFLAGS.MF_SEPARATOR | ShellExtLib.UFLAGS.MF_BYPOSITION, 0, null);
return (int)(idCmd - idCmdFirst);
}
}
catch { }
return 0;
}
void ShellExtLib.IContextMenu.GetCommandString(int idCmd, uint uFlags, int pwReserved, StringBuilder commandString, int cchMax)
{
switch (uFlags)
{
case (uint)ShellExtLib.GCS.VERB:
commandString = new StringBuilder("x");
break;
case (uint)ShellExtLib.GCS.HELPTEXTA:
commandString = new StringBuilder("y");
break;
}
}
有没有人有什么建议?我已经阅读了许多关于如何构建 shell 扩展的文章,并且也一直在阅读 MSDN。
谢谢。