Use symbolic constants for list model columns in dataview sample.

Using Col_EditableText, Col_IconText and Col_TextWithAttr instead of 0, 1 and
2 makes the sample code a bit easier to read.

Also use switch on the column value instead of nested ifs everywhere to give
compiler a chance to warn us if we forget to update some function when a new
column is added.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@62587 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

samples/dataview/dataview.cpp

@@ -545,10 +545,17 @@ void MyFrame::BuildDataViewCtrl(wxPanel* parent, unsigned int nPanel, unsigned l
             m_ctrl[1]->AssociateModel( m_list_model.get() );
 
             // the various columns
-            m_ctrl[1]->AppendTextColumn("editable string", 0, wxDATAVIEW_CELL_EDITABLE);
+            m_ctrl[1]->AppendTextColumn("editable string",
-            m_ctrl[1]->AppendIconTextColumn("icon", 1, wxDATAVIEW_CELL_EDITABLE);
+                                        MyListModel::Col_EditableText,
+                                        wxDATAVIEW_CELL_EDITABLE);
+            m_ctrl[1]->AppendIconTextColumn("icon",
+                                            MyListModel::Col_IconText,
+                                            wxDATAVIEW_CELL_EDITABLE);
             m_ctrl[1]->AppendColumn(
-                new wxDataViewColumn("attributes", new wxDataViewTextRenderer, 2 ));
+                new wxDataViewColumn("attributes",
+                                     new wxDataViewTextRenderer,
+                                     MyListModel::Col_TextWithAttr)
+            );
         }
         break;
 

samples/dataview/mymodels.cpp

@@ -404,14 +404,16 @@ void MyListModel::AddMany()
 void MyListModel::GetValueByRow( wxVariant &variant,
                                  unsigned int row, unsigned int col ) const
 {
-    if (col==0)
+    switch ( col )
     {
+        case Col_EditableText:
             if (row >= m_textColValues.GetCount())
                 variant = wxString::Format( "virtual row %d", row );
             else
                 variant = m_textColValues[ row ];
-    }
+            break;
-    else if (col==1)
+
+        case Col_IconText:
             {
                 wxString text;
                 if ( row >= m_iconColValues.GetCount() )
@@ -421,7 +423,9 @@ void MyListModel::GetValueByRow( wxVariant &variant,
 
                 variant << wxDataViewIconText(text, m_icon[row % 2]);
             }
-    else if (col==2)
+            break;
+
+        case Col_TextWithAttr:
             {
                 static const char *labels[5] =
                 {
@@ -430,6 +434,11 @@ void MyListModel::GetValueByRow( wxVariant &variant,
 
                 variant = labels[row % 5];
             }
+            break;
+
+        case Col_Max:
+            wxFAIL_MSG( "invalid column" );
+    }
 }
 
 bool MyListModel::GetAttrByRow( unsigned int row, unsigned int col,
@@ -437,16 +446,16 @@ bool MyListModel::GetAttrByRow( unsigned int row, unsigned int col,
 {
     switch ( col )
     {
-        case 0:
+        case Col_EditableText:
             return false;
 
-        case 1:
+        case Col_IconText:
             if ( !(row % 2) )
                 return false;
             attr.SetColour(*wxLIGHT_GREY);
             break;
 
-        case 2:
+        case Col_TextWithAttr:
             // do what the labels defined above hint at
             switch ( row % 5 )
             {
@@ -471,6 +480,9 @@ bool MyListModel::GetAttrByRow( unsigned int row, unsigned int col,
                     return false;
             }
             break;
+
+        case Col_Max:
+            wxFAIL_MSG( "invalid column" );
     }
 
     return true;
@@ -481,8 +493,8 @@ bool MyListModel::SetValueByRow( const wxVariant &variant,
 {
     switch ( col )
     {
-        case 0:
+        case Col_EditableText:
-        case 1:
+        case Col_IconText:
             if (row >= m_textColValues.GetCount())
             {
                 // the item is not in the range of the items
@@ -492,22 +504,25 @@ bool MyListModel::SetValueByRow( const wxVariant &variant,
                 return false;
             }
 
-            if ( col == 0 )
+            if ( col == Col_EditableText )
             {
                 m_textColValues[row] = variant.GetString();
             }
-            else // col == 1
+            else // col == Col_IconText
             {
                 wxDataViewIconText iconText;
                 iconText << variant;
                 m_iconColValues[row] = iconText.GetText();
             }
+            return true;
+
+        case Col_TextWithAttr:
+            wxLogError("Cannot edit the column %d", col);
             break;
 
-        default:
+        case Col_Max:
-            wxLogError("Cannot edit the column %d", col);
+            wxFAIL_MSG( "invalid column" );
-            return false;
     }
 
-    return true;
+    return false;
 }

samples/dataview/mymodels.h

@@ -188,6 +188,14 @@ private:
 class MyListModel: public wxDataViewVirtualListModel
 {
 public:
+    enum
+    {
+        Col_EditableText,
+        Col_IconText,
+        Col_TextWithAttr,
+        Col_Max
+    };
+
     MyListModel();
 
     // helper methods to change the model
@@ -202,12 +210,12 @@ public:
 
     virtual unsigned int GetColumnCount() const
     {
-        return 3;
+        return Col_Max;
     }
 
     virtual wxString GetColumnType( unsigned int col ) const
     {
-        if (col == 1)
+        if (col == Col_IconText)
             return wxT("wxDataViewIconText");
 
         return wxT("string");