📄 gridctrl_combo.shtml
字号:
<HTML><HEAD> <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1"> <META NAME="Author" CONTENT="Chris Maunder"> <TITLE>Controls - Using a Combobox to edit cells in the Grid Control</TITLE></HEAD><!-- document properties --><body background="../fancyhome/back.gif" bgcolor="#FFFFFF" link="#B50029" vlink="#8E2323" alink="#FF0000"><!-- advertisment --><table WIDTH="100%"><tr WIDTH="100%"><td><!--#exec cgi="/cgi/ads.cgi"--><td></tr></table><!-- Title --><CENTER><H3><FONT COLOR="#AOAO99">Using a Combobox to edit cells in the Grid Control</FONT></H3></CENTER><HR>This article was contributed by <A HREF="mailto:Chris.Maunder@cbr.clw.csiro.au">Chris Maunder</A>.<!-- Image and download files --><P><IMG SRC="gridctrl_combo.gif" width="274" height="213" ALT="gridctrl with combo example image" BORDER=0 ALIGN=BOTTOM>Download <A HREF="gridctrl_combo_demo.zip">sample project</A>.</p><!-- Environment --><u>Environment:</u> VC++ 5.0 (SP3) NT 4.0 (SP3), Win95<!-- the article... --><p>Since I posted my <a href="gridctrl.shtml">MFC grid control</a> I've had a lotof requests asking how to use other methods of editing cells in the grid. I'vecreated a demo project that shows how to replace the default editing with a dropdown list of choices. This is achieved by deriving a new class from CGridCtrland overridding CGridCtrl::OnEditCell.<p>The In-Place list that I use to edit the cells instead of the in-place editcontrol is not the greatest - but it does demonstrate how to replace the defaulteditting.<br><br><p>The first step is to derive a new class from CGridCtrl - I call itCComboGridCtrl - and override OnEditCell. There are a number of thingsto be aware of when you override this function. OnEditCell receives therow and column to be edited plus the initial character that causedediting to commence (or VK_LBUTTON if the mouse was clicked on the currentcell). <ul><li>You must check that the cell given by (row, column) is valid, thatit is visible, and that it (and the grid in general) is in fact editable.<li>You must send a GVN_BEGINLABELEDIT notification message to the parentto inform it that editing will be commencing.<li>Your editing control must self-delete when it loses input focus.<li>Your editing object should handle mouse keys in a way that allowsthe user to navigate between cells while editing. If the control gets anarrow key for instance, it should cancel editing and return the last keyit encountered back to the grid via the GVN_ENDLABELEDIT notificationmessage.</ul><p>I pass the character that initiated editing to the edit control itself sothat it can deal with keys appropriately. For instance in the default edit control,if the edit control is passed a normal character or arrow key as the "initiating"key, then it will cease editing when it encounters an arrow key (to allow navigationusing the keyboard). If the edit control is passed VK_LBUTTON (meaning editingwas initiated by a mouse click) then arrow keys will not cause the editing tocease.<p>Once the control has finished editing (for whatever reason) it shouldsend a GVN_ENDLABELEDIT notification using the following code as an example: <FONT COLOR="#990000"><TT><PRE> // This code should appear in your editing control (editbox, list etc) // Send Notification that editing has finished to the parent grid GV_DISPINFO dispinfo; dispinfo.hdr.hwndFrom = GetSafeHwnd(); dispinfo.hdr.idFrom = GetDlgCtrlID(); dispinfo.hdr.code = GVN_ENDLABELEDIT; dispinfo.item.mask = LVIF_TEXT|LVIF_PARAM; dispinfo.item.row = m_nRow; dispinfo.item.col = m_nCol; dispinfo.item.szText = str; dispinfo.item.lParam = (LPARAM) m_nLastChar; CWnd* pOwner = GetOwner(); if (IsWindow(pOwner->GetSafeHwnd())) pOwner->SendMessage(WM_NOTIFY, GetDlgCtrlID(), (LPARAM)&dispinfo );</tt></PRE></FONT><p>where m_nRow and m_nColumn are member variables of the edit control that wereused to store the row and column, and m_nLastChar stores the value of the lastcharacter encountered by the control. See the <a href="gridctrl.shtml">GridCtrl</a>docs for more info on the GV_DISPINFO structure.<p>To actually catch the GVN_ENDLABELEDIT notification in your derived grid youshould place a message map entry as such:<FONT COLOR="#990000"><TT><PRE>BEGIN_MESSAGE_MAP(CComboGridCtrl, CGridCtrl) //{{AFX_MSG_MAP(CComboGridCtrl) //}}AFX_MSG_MAP ON_NOTIFY(GVN_ENDLABELEDIT, IDC_IPLIST, OnEndInPlaceEdit)END_MESSAGE_MAP()</tt></PRE></FONT><p>where IDC_IPLIST is the ID of the drop down list control used to edit the cells.<p>Once you have an edit control ready to be used, override OnEditCell and useyour own edit control instead of the default in-place edit control.<FONT COLOR="#990000"><TT><PRE>void CComboGridCtrl::OnEditCell(int nRow, int nCol, UINT nChar){ CCellID cell(nRow, nCol); if (!m_bEditable ||!IsCellVisible(nRow, nCol) || !IsValid(cell)) return; if (GetItemState(nRow, nCol) & GVIS_READONLY) return; CRect rect; if (!GetCellRect(cell, rect)) return; // Send message to parent letting it know we are about to edit NM_GRIDVIEW nmgv; nmgv.iRow = nRow; nmgv.iColumn = nCol; nmgv.hdr.hwndFrom = m_hWnd; nmgv.hdr.idFrom = GetDlgCtrlID(); nmgv.hdr.code = GVN_BEGINLABELEDIT; CWnd* pParent = GetOwner(); if (pParent) pParent->SendMessage(WM_NOTIFY, nmgv.hdr.idFrom, (LPARAM)&nmgv); // Fill a string array with possible choices for the list control to present. CString text = GetItemText(nRow, nCol); CStringArray Items; Items.Add("Choice 1"); Items.Add("Choice 2"); Items.Add("Choice 3"); Items.Add("Choice 4"); Items.Add("Choice 5"); // InPlaceList and auto-deletes itself new CInPlaceList(this, // parent of the edit control (this grid) rect, // cell boundary nRow, nCol, // Row and Column Items, // A list of items for the drop down list text, // Initial selection nChar); // Character that cuased editing (may be VK_LBUTTON)}</tt></PRE></FONT><p>The <A HREF="gridctrl_demo.zip">sample project</A> includes the source code for the CInPlaceList control presentedabove.<br><P>Last Updated: June 16, 1998.<P><HR><!-- Contact details --><TABLE BORDER=0 WIDTH="100%"><TR><TD WIDTH="33%"><FONT SIZE=-1><A HREF="http://www.codeguru.com">Goto HomePage</A></FONT></TD><TD WIDTH="33%"><CENTER><FONT SIZE=-2>© 1997 Zafir Anjum</FONT> </CENTER></TD><TD WIDTH="34%"><DIV ALIGN=right><FONT SIZE=-1>Contact me: <A HREF="mailto:zafir@home.com">zafir@home.com</A> </FONT></DIV></TD></TR></TABLE><!-- Counter --><CENTER><FONT SIZE=-2><!--#exec cgi="../cgi/counters/counter.cgi"--></FONT></CENTER></BODY></HTML>⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -