return the correct number of columns from wxGridStringTable, even when we don't have any rows (closes #10818)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@60717 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/generic/grid.h

@@ -729,10 +729,10 @@ public:
 
     // these are pure virtual in wxGridTableBase
     //
-    int GetNumberRows();
+    virtual int GetNumberRows() { return m_data.size(); }
-    int GetNumberCols();
+    virtual int GetNumberCols() { return m_numCols; }
-    wxString GetValue( int row, int col );
+    virtual wxString GetValue( int row, int col );
-    void SetValue( int row, int col, const wxString& s );
+    virtual void SetValue( int row, int col, const wxString& s );
 
     // overridden functions from wxGridTableBase
     //
@@ -752,6 +752,12 @@ public:
 private:
     wxGridStringArray m_data;
 
+    // notice that while we don't need to store the number of our rows as it's
+    // always equal to the size of m_data array, we do need to store the number
+    // of our columns as we can't retrieve it from m_data when the number of
+    // rows is 0 (see #10818)
+    int m_numCols;
+
     // These only get used if you set your own labels, otherwise the
     // GetRow/ColLabelValue functions return wxGridTableBase defaults
     //

src/generic/grid.cpp

@@ -1127,11 +1127,14 @@ IMPLEMENT_DYNAMIC_CLASS( wxGridStringTable, wxGridTableBase )
 wxGridStringTable::wxGridStringTable()
         : wxGridTableBase()
 {
+    m_numCols = 0;
 }
 
 wxGridStringTable::wxGridStringTable( int numRows, int numCols )
         : wxGridTableBase()
 {
+    m_numCols = numCols;
+
     m_data.Alloc( numRows );
 
     wxArrayString sa;
@@ -1145,19 +1148,6 @@ wxGridStringTable::~wxGridStringTable()
 {
 }
 
-int wxGridStringTable::GetNumberRows()
-{
-    return m_data.GetCount();
-}
-
-int wxGridStringTable::GetNumberCols()
-{
-    if ( m_data.GetCount() > 0 )
-        return m_data[0].GetCount();
-    else
-        return 0;
-}
-
 wxString wxGridStringTable::GetValue( int row, int col )
 {
     wxCHECK_MSG( (row < GetNumberRows()) && (col < GetNumberCols()),
@@ -1327,6 +1317,8 @@ bool wxGridStringTable::InsertCols( size_t pos, size_t numCols )
         }
     }
 
+    m_numCols += numCols;
+
     if ( GetView() )
     {
         wxGridTableMessage msg( this,
@@ -1351,6 +1343,8 @@ bool wxGridStringTable::AppendCols( size_t numCols )
         m_data[row].Add( wxEmptyString, numCols );
     }
 
+    m_numCols += numCols;
+
     if ( GetView() )
     {
         wxGridTableMessage msg( this,
@@ -1404,16 +1398,23 @@ bool wxGridStringTable::DeleteCols( size_t pos, size_t numCols )
             m_colLabels.RemoveAt( colID, nToRm );
     }
 
-    for ( row = 0; row < curNumRows; row++ )
+    if ( numCols >= curNumCols )
     {
-        if ( numCols >= curNumCols )
+        for ( row = 0; row < curNumRows; row++ )
         {
             m_data[row].Clear();
         }
-        else
+
+        m_numCols = 0;
+    }
+    else // something will be left
+    {
+        for ( row = 0; row < curNumRows; row++ )
         {
             m_data[row].RemoveAt( colID, numCols );
         }
+
+        m_numCols -= numCols;
     }
 
     if ( GetView() )