From d7eee191c55687785a2be927fd387d10514cdf1b Mon Sep 17 00:00:00 2001
From: Vadim Zeitlin <vadim@wxwidgets.org>
Date: Wed, 15 Aug 2001 12:45:53 +0000
Subject: [PATCH] implemented, tested and documented wxTextCtrl::SetMaxLength()

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@11383 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
---
 docs/changes.txt           |  1 +
 docs/latex/wx/cmdevent.tex |  4 ++++
 docs/latex/wx/text.tex     | 22 ++++++++++++++++++++
 include/wx/event.h         |  1 +
 include/wx/gtk/textctrl.h  |  2 ++
 include/wx/gtk1/textctrl.h |  2 ++
 include/wx/msw/textctrl.h  | 17 +++++++++------
 include/wx/textctrl.h      |  6 ++++++
 samples/text/text.cpp      | 17 +++++++++++++++
 src/common/textcmn.cpp     |  1 +
 src/gtk/textctrl.cpp       |  8 ++++++++
 src/gtk1/textctrl.cpp      |  8 ++++++++
 src/msw/textctrl.cpp       | 42 ++++++++++++++++++++++++++++++++------
 13 files changed, 119 insertions(+), 12 deletions(-)

diff --git a/docs/changes.txt b/docs/changes.txt
index 729bcef7a8..48d3c7cc7c 100644
--- a/docs/changes.txt
+++ b/docs/changes.txt
@@ -15,6 +15,7 @@ All (GUI):
 
 - support for virtual list control added
 - wxFindReplaceDialog added (based on work of Markus Greither)
+- wxTextCtrl::SetMaxLength() added (wxMSW/wxGTK)
 
 wxHTML:
 
diff --git a/docs/latex/wx/cmdevent.tex b/docs/latex/wx/cmdevent.tex
index 973f3956de..f129cfc0ce 100644
--- a/docs/latex/wx/cmdevent.tex
+++ b/docs/latex/wx/cmdevent.tex
@@ -39,6 +39,10 @@ which is generated by a wxTextCtrl control.}
 which is generated by a wxTextCtrl control. Note that you must use
 wxTE\_PROCESS\_ENTER flag when creating the control if you want it to generate
 such events.}
+\twocolitem{{\bf EVT\_TEXT\_MAXLEN(id, func)}}{Process a wxEVT\_COMMAND\_TEXT\_MAXLEN command,
+which is generated by a wxTextCtrl control when the user tries to enter more
+characters into it than the limit previosuly set with 
+\helpref{SetMaxLength}{wxtextctrlsetmaxlength}.}
 \twocolitem{{\bf EVT\_MENU(id, func)}}{Process a wxEVT\_COMMAND\_MENU\_SELECTED command,
 which is generated by a menu item.}
 \twocolitem{{\bf EVT\_MENU\_RANGE(id1, id2, func)}}{Process a wxEVT\_COMMAND\_MENU\_RANGE command,
diff --git a/docs/latex/wx/text.tex b/docs/latex/wx/text.tex
index 2d5697d970..a9c2117f2d 100644
--- a/docs/latex/wx/text.tex
+++ b/docs/latex/wx/text.tex
@@ -514,6 +514,28 @@ Sets the insertion point at the given position.
 Sets the insertion point at the end of the text control. This is equivalent
 to \helpref{SetInsertionPoint}{wxtextctrlsetinsertionpoint}(\helpref{GetLastPosition}{wxtextctrlgetlastposition}()).
 
+\membersection{wxTextCtrl::SetMaxLength}\label{wxtextctrlsetmaxlength}
+
+\func{virtual void}{SetMaxLength}{\param{unsigned long }{len}}
+
+This function sets the maximum number of characters the user can enter into the
+control. In other words, it allows to limit the text value length to {\it len}
+not counting the terminating {\tt NUL} character.
+
+If the user tries to enter more characters into the text control when it
+already is filled up to the maximal length, a 
+{\tt wxEVT\_COMMAND\_TEXT\_MAXLEN} event is sent to notify the program about it
+(giving it the possibility to show an explanatory message, for example) and the
+extra input is discarded.
+
+Note that this function may only be used with single line text controls.
+
+\wxheading{Compatibility}
+
+Only implemented in wxMSW/wxGTK starting with wxWindows 2.3.2.
+
+The {\tt wxEVT\_COMMAND\_TEXT\_MAXLEN} event is only sent by wxMSW.
+
 \membersection{wxTextCtrl::SetSelection}\label{wxtextctrlsetselection}
 
 \func{virtual void}{SetSelection}{\param{long}{ from}, \param{long}{ to}}
diff --git a/include/wx/event.h b/include/wx/event.h
index d3daa5b71e..19922acda2 100644
--- a/include/wx/event.h
+++ b/include/wx/event.h
@@ -120,6 +120,7 @@ BEGIN_DECLARE_EVENT_TYPES()
     DECLARE_EVENT_TYPE(wxEVT_COMMAND_TEXT_UPDATED, 7)
     DECLARE_EVENT_TYPE(wxEVT_COMMAND_TEXT_ENTER, 8)
     DECLARE_EVENT_TYPE(wxEVT_COMMAND_TEXT_URL, 13)
+    DECLARE_EVENT_TYPE(wxEVT_COMMAND_TEXT_MAXLEN, 14)
 #endif // WXWIN_COMPATIBILITY_EVENT_TYPES
     DECLARE_EVENT_TYPE(wxEVT_COMMAND_MENU_SELECTED, 9)
     DECLARE_EVENT_TYPE(wxEVT_COMMAND_SLIDER_UPDATED, 10)
diff --git a/include/wx/gtk/textctrl.h b/include/wx/gtk/textctrl.h
index 085d5ca4b6..5a5ab756ff 100644
--- a/include/wx/gtk/textctrl.h
+++ b/include/wx/gtk/textctrl.h
@@ -74,6 +74,8 @@ public:
     // clears the dirty flag
     virtual void DiscardEdits();
 
+    virtual void SetMaxLength(unsigned long len);
+
     // writing text inserts it at the current position, appending always
     // inserts it at the end
     virtual void WriteText(const wxString& text);
diff --git a/include/wx/gtk1/textctrl.h b/include/wx/gtk1/textctrl.h
index 085d5ca4b6..5a5ab756ff 100644
--- a/include/wx/gtk1/textctrl.h
+++ b/include/wx/gtk1/textctrl.h
@@ -74,6 +74,8 @@ public:
     // clears the dirty flag
     virtual void DiscardEdits();
 
+    virtual void SetMaxLength(unsigned long len);
+
     // writing text inserts it at the current position, appending always
     // inserts it at the end
     virtual void WriteText(const wxString& text);
diff --git a/include/wx/msw/textctrl.h b/include/wx/msw/textctrl.h
index b76a6d5fb8..d2d7315e4e 100644
--- a/include/wx/msw/textctrl.h
+++ b/include/wx/msw/textctrl.h
@@ -1,5 +1,5 @@
 /////////////////////////////////////////////////////////////////////////////
-// Name:        textctrl.h
+// Name:        wx/msw/textctrl.h
 // Purpose:     wxTextCtrl class
 // Author:      Julian Smart
 // Modified by:
@@ -72,6 +72,8 @@ public:
     // clears the dirty flag
     virtual void DiscardEdits();
 
+    virtual void SetMaxLength(unsigned long len);
+
     // writing text inserts it at the current position, appending always
     // inserts it at the end
     virtual void WriteText(const wxString& text);
@@ -164,18 +166,21 @@ public:
     void OnUpdateRedo(wxUpdateUIEvent& event);
 
 protected:
-#if wxUSE_RICHEDIT
-    bool      m_isRich; // Are we using rich text edit to implement this?
-#endif
-
     // call this to increase the size limit (will do nothing if the current
     // limit is big enough)
-    void AdjustSpaceLimit();
+    //
+    // returns true if we increased the limit to allow entering more text,
+    // false if we hit the limit set by SetMaxLength() and so didn't change it
+    bool AdjustSpaceLimit();
 
     // override some base class virtuals
     virtual bool MSWShouldPreProcessMessage(WXMSG* pMsg);
     virtual wxSize DoGetBestSize() const;
 
+#if wxUSE_RICHEDIT
+    bool m_isRich; // Are we using rich text edit to implement this?
+#endif
+
 private:
     DECLARE_EVENT_TABLE()
     DECLARE_DYNAMIC_CLASS(wxTextCtrl)
diff --git a/include/wx/textctrl.h b/include/wx/textctrl.h
index f70f125f4c..94a65ac2c3 100644
--- a/include/wx/textctrl.h
+++ b/include/wx/textctrl.h
@@ -174,6 +174,10 @@ public:
     // clears the dirty flag
     virtual void DiscardEdits() = 0;
 
+    // set the max number of characters which may be entered in a single line
+    // text control
+    virtual void SetMaxLength(unsigned long WXUNUSED(len)) { }
+
     // writing text inserts it at the current position, appending always
     // inserts it at the end
     virtual void WriteText(const wxString& text) = 0;
@@ -289,6 +293,7 @@ BEGIN_DECLARE_EVENT_TYPES()
     DECLARE_EVENT_TYPE(wxEVT_COMMAND_TEXT_UPDATED, 7)
     DECLARE_EVENT_TYPE(wxEVT_COMMAND_TEXT_ENTER, 8)
     DECLARE_EVENT_TYPE(wxEVT_COMMAND_TEXT_URL, 13)
+    DECLARE_EVENT_TYPE(wxEVT_COMMAND_TEXT_MAXLEN, 14)
 END_DECLARE_EVENT_TYPES()
 
 #endif // !WXWIN_COMPATIBILITY_EVENT_TYPES
@@ -332,6 +337,7 @@ typedef void (wxEvtHandler::*wxTextUrlEventFunction)(wxTextUrlEvent&);
 #define EVT_TEXT(id, fn) DECLARE_EVENT_TABLE_ENTRY( wxEVT_COMMAND_TEXT_UPDATED, id, -1, (wxObjectEventFunction) (wxEventFunction) (wxCommandEventFunction) & fn, (wxObject *) NULL ),
 #define EVT_TEXT_ENTER(id, fn) DECLARE_EVENT_TABLE_ENTRY( wxEVT_COMMAND_TEXT_ENTER, id, -1, (wxObjectEventFunction) (wxEventFunction) (wxCommandEventFunction) & fn, (wxObject *) NULL ),
 #define EVT_TEXT_URL(id, fn) DECLARE_EVENT_TABLE_ENTRY( wxEVT_COMMAND_TEXT_URL, id, -1, (wxObjectEventFunction) (wxEventFunction) (wxCommandEventFunction) (wxTextUrlEventFunction) & fn, (wxObject *) NULL ),
+#define EVT_TEXT_MAXLEN(id, fn) DECLARE_EVENT_TABLE_ENTRY( wxEVT_COMMAND_TEXT_MAXLEN, id, -1, (wxObjectEventFunction) (wxEventFunction) (wxCommandEventFunction) & fn, (wxObject *) NULL ),
 
 #endif // wxUSE_TEXTCTRL
 
diff --git a/samples/text/text.cpp b/samples/text/text.cpp
index cda6812c40..ac11396a01 100644
--- a/samples/text/text.cpp
+++ b/samples/text/text.cpp
@@ -66,8 +66,11 @@ public:
     void OnKeyDown(wxKeyEvent& event);
     void OnKeyUp(wxKeyEvent& event);
     void OnChar(wxKeyEvent& event);
+
     void OnText(wxCommandEvent& event);
     void OnTextURL(wxTextUrlEvent& event);
+    void OnTextMaxLen(wxCommandEvent& event);
+
     void OnMouseEvent(wxMouseEvent& event);
 
     bool m_hasCapture;
@@ -99,6 +102,7 @@ public:
     MyTextCtrl    *m_enter;
     MyTextCtrl    *m_tab;
     MyTextCtrl    *m_readonly;
+    MyTextCtrl    *m_limited;
 
     MyTextCtrl    *m_multitext;
     MyTextCtrl    *m_horizontal;
@@ -308,8 +312,11 @@ BEGIN_EVENT_TABLE(MyTextCtrl, wxTextCtrl)
     EVT_KEY_DOWN(MyTextCtrl::OnKeyDown)
     EVT_KEY_UP(MyTextCtrl::OnKeyUp)
     EVT_CHAR(MyTextCtrl::OnChar)
+
     EVT_TEXT(-1, MyTextCtrl::OnText)
     EVT_TEXT_URL(-1, MyTextCtrl::OnTextURL)
+    EVT_TEXT_MAXLEN(-1, MyTextCtrl::OnTextMaxLen)
+
     EVT_MOUSE_EVENTS(MyTextCtrl::OnMouseEvent)
 END_EVENT_TABLE()
 
@@ -524,6 +531,11 @@ void MyTextCtrl::OnText(wxCommandEvent& event)
     }
 }
 
+void MyTextCtrl::OnTextMaxLen(wxCommandEvent& event)
+{
+    wxLogMessage(_T("You can't enter more characters into this control."));
+}
+
 void MyTextCtrl::OnTextURL(wxTextUrlEvent& event)
 {
     const wxMouseEvent& ev = event.GetMouseEvent();
@@ -667,6 +679,10 @@ MyPanel::MyPanel( wxFrame *frame, int x, int y, int w, int h )
     m_readonly = new MyTextCtrl( this, -1, "Read only",
       wxPoint(10,90), wxSize(140,-1), wxTE_READONLY );
 
+    m_limited = new MyTextCtrl(this, -1, "Max 8 ch",
+                              wxPoint(10, 130), wxSize(140, -1));
+    m_limited->SetMaxLength(8);
+
     // multi line text controls
 
     m_horizontal = new MyTextCtrl( this, -1, "Multiline text control with a horizontal scrollbar.",
@@ -990,6 +1006,7 @@ void MyFrame::OnSetEnabled(wxCommandEvent& WXUNUSED(event))
     m_panel->m_password->Enable(enabled);
     m_panel->m_multitext->Enable(enabled);
     m_panel->m_readonly->Enable(enabled);
+    m_panel->m_limited->Enable(enabled);
     m_panel->m_textrich->Enable(enabled);
 }
 
diff --git a/src/common/textcmn.cpp b/src/common/textcmn.cpp
index 523b23085c..7ced7d2de5 100644
--- a/src/common/textcmn.cpp
+++ b/src/common/textcmn.cpp
@@ -51,6 +51,7 @@ IMPLEMENT_DYNAMIC_CLASS(wxTextUrlEvent, wxCommandEvent)
 DEFINE_EVENT_TYPE(wxEVT_COMMAND_TEXT_UPDATED)
 DEFINE_EVENT_TYPE(wxEVT_COMMAND_TEXT_ENTER)
 DEFINE_EVENT_TYPE(wxEVT_COMMAND_TEXT_URL)
+DEFINE_EVENT_TYPE(wxEVT_COMMAND_TEXT_MAXLEN)
 
 // ----------------------------------------------------------------------------
 // ctor
diff --git a/src/gtk/textctrl.cpp b/src/gtk/textctrl.cpp
index f16643b0c7..0e2fab3a26 100644
--- a/src/gtk/textctrl.cpp
+++ b/src/gtk/textctrl.cpp
@@ -826,6 +826,14 @@ void wxTextCtrl::DiscardEdits()
     m_modified = FALSE;
 }
 
+void wxTextCtrl::SetMaxLength(unsigned long len)
+{
+    if ( !HasFlag(wxTE_MULTILINE) )
+    {
+        gtk_entry_set_max_length(GTK_ENTRY(m_text), len);
+    }
+}
+
 void wxTextCtrl::SetSelection( long from, long to )
 {
     wxCHECK_RET( m_text != NULL, wxT("invalid text ctrl") );
diff --git a/src/gtk1/textctrl.cpp b/src/gtk1/textctrl.cpp
index f16643b0c7..0e2fab3a26 100644
--- a/src/gtk1/textctrl.cpp
+++ b/src/gtk1/textctrl.cpp
@@ -826,6 +826,14 @@ void wxTextCtrl::DiscardEdits()
     m_modified = FALSE;
 }
 
+void wxTextCtrl::SetMaxLength(unsigned long len)
+{
+    if ( !HasFlag(wxTE_MULTILINE) )
+    {
+        gtk_entry_set_max_length(GTK_ENTRY(m_text), len);
+    }
+}
+
 void wxTextCtrl::SetSelection( long from, long to )
 {
     wxCHECK_RET( m_text != NULL, wxT("invalid text ctrl") );
diff --git a/src/msw/textctrl.cpp b/src/msw/textctrl.cpp
index c6beb418d7..391af4da13 100644
--- a/src/msw/textctrl.cpp
+++ b/src/msw/textctrl.cpp
@@ -878,6 +878,11 @@ wxString wxTextCtrl::GetLineText(long lineNo) const
     return str;
 }
 
+void wxTextCtrl::SetMaxLength(unsigned long len)
+{
+    ::SendMessage(GetHwnd(), EM_LIMITTEXT, len, 0);
+}
+
 // ----------------------------------------------------------------------------
 // Undo/redo
 // ----------------------------------------------------------------------------
@@ -1020,8 +1025,8 @@ bool wxTextCtrl::MSWCommand(WXUINT param, WXWORD WXUNUSED(id))
         case EN_KILLFOCUS:
             {
                 wxFocusEvent event(param == EN_KILLFOCUS ? wxEVT_KILL_FOCUS
-                        : wxEVT_SET_FOCUS,
-                        m_windowId);
+                                                         : wxEVT_SET_FOCUS,
+                                   m_windowId);
                 event.SetEventObject( this );
                 GetEventHandler()->ProcessEvent(event);
             }
@@ -1038,7 +1043,13 @@ bool wxTextCtrl::MSWCommand(WXUINT param, WXWORD WXUNUSED(id))
 
         case EN_MAXTEXT:
             // the text size limit has been hit - increase it
-            AdjustSpaceLimit();
+            if ( !AdjustSpaceLimit() )
+            {
+                wxCommandEvent event(wxEVT_COMMAND_TEXT_MAXLEN, m_windowId);
+                InitCommandEvent(event);
+                event.SetString(GetValue());
+                ProcessCommand(event);
+            }
             break;
 
             // the other notification messages are not processed
@@ -1127,11 +1138,27 @@ void wxTextCtrl::OnEraseBackground(wxEraseEvent& event)
 }
 #endif
 
-void wxTextCtrl::AdjustSpaceLimit()
+bool wxTextCtrl::AdjustSpaceLimit()
 {
 #ifndef __WIN16__
-    unsigned int len = ::GetWindowTextLength(GetHwnd()),
-    limit = ::SendMessage(GetHwnd(), EM_GETLIMITTEXT, 0, 0);
+    unsigned int limit = ::SendMessage(GetHwnd(), EM_GETLIMITTEXT, 0, 0);
+
+    // HACK: we try to automatically extend the limit for the amount of text
+    //       to allow (interactively) entering more than 64Kb of text under
+    //       Win9x but we shouldn't reset the text limit which was previously
+    //       set explicitly with SetMaxLength()
+    //
+    //       we could solve this by storing the limit we set in wxTextCtrl but
+    //       to save space we prefer to simply test here the actual limit
+    //       value: we consider that SetMaxLength() can only be called for
+    //       values < 32Kb
+    if ( limit < 0x8000 )
+    {
+        // we've got more text than limit set by SetMaxLength()
+        return FALSE;
+    }
+
+    unsigned int len = ::GetWindowTextLength(GetHwnd());
     if ( len >= limit )
     {
         limit = len + 0x8000;    // 32Kb
@@ -1156,6 +1183,9 @@ void wxTextCtrl::AdjustSpaceLimit()
         }
     }
 #endif // !Win16
+
+    // we changed the limit
+    return TRUE;
 }
 
 bool wxTextCtrl::AcceptsFocus() const
-- 
2.50.0

