HELP Sorting data in StringGrid

[Burtlancaster]

I have a data currently loaded in to a StringGrid, does anyone know how I can sort this data. For example the Grid has 3 columns (Name, Date, Time) and I need the ability to sort by the 3 columns whilst keep the data appended to its original string.

Thanks for looking.

 

[2ffat]

LastCyborg had a solution in thread101-872830. Maybe he can post more info here.

I've seen pascal code to do it but not C++.

James P. Cottingham

^{There's no place like 127.0.0.1.
There's no place like 127.0.0.1.}

 

[LastCyborg]

Ok, but as I said this is for TListView Components, I hope it helps.

First:
This is a library so just copy and paste it after that save it with any name (I suggest "ListManager.h").

#ifndef ListManagerH
#define ListManagerH
//---------------------------------------------------------------------------
template <class T> class ListViewManager : public TComponent
{
protected:
   TLVDeletedEvent     OldOnDelete;
   TLVCompareEvent     OldOnCompare;
   TLVColumnClickEvent OldOnColumnClick;
   int iCurrentSort;
public:
   TListView* lvList;
   __fastcall ListViewManager(TListView* pList);
   TListItem* AddObject(T* pObj);
   void RefreshObject(T* pObj);
   void RefreshItem(TListItem* item);
   void __fastcall OnListViewDeletion(TObject *Sender, TListItem *Item);
   void __fastcall OnListViewColumnClick(TObject *Sender, TListColumn *Column);
   void __fastcall OnListViewCompare(TObject *Sender, TListItem *Item1,
                                    TListItem *Item2, int Data, int &Compare);
};
//---------------------------------------------------------------------------
template <class T>
__fastcall ListViewManager<T>::ListViewManager(TListView* pList)
  : TComponent(pList)
{
   lvList = pList;
   iCurrentSort = -1;
   // Save previous event handlers defined in DFM
   OldOnDelete = lvList->OnDeletion;
   OldOnCompare = lvList->OnCompare;
   OldOnColumnClick = lvList->OnColumnClick;
   // Assign new event handlers
   lvList->OnDeletion    = OnListViewDeletion;
   lvList->OnCompare     = OnListViewCompare;
   lvList->OnColumnClick = OnListViewColumnClick;
}
//---------------------------------------------------------------------------
// This function updates the column text of the specified object
template<class T>
void ListViewManager<T>::RefreshObject(T* pObj)
{
   TListItem* pItem = FindObject(pObj);
   if (pItem)
      RefreshItem(pItem);
}
//---------------------------------------------------------------------------
// Function RefreshItem() updates the columns of text
// and the icon for an object in the listview.
template<class T>
void ListViewManager<T>::RefreshItem(TListItem* item)
{
   if (item)
   {
      T* pObject = (T*)(item->Data);
      if (pObject)
      {
         item->SubItems->Clear();
         for (int i = 0; i < lvList->Columns->Count; i++)
           if (i == 0)
             item->Caption = pObject->GetColumnString(i);
           else
             item->SubItems->Add(pObject->GetColumnString(i));
       }
   }
}
//---------------------------------------------------------------------------
// Function AddItem() adds an object to the listview and
// automatically sets the text of all the columns.
template <class T>
TListItem* ListViewManager<T>::AddObject(T* pObject)
{
   TListItem* item = lvList->Items->Add();
   item->Data = (TObject*)pObject;
   RefreshItem(item);
   return item;
}
//---------------------------------------------------------------------------
// This event ensures that the objects will get deleted
// when the listview is deleted.
template <class T>
void __fastcall ListViewManager<T>::OnListViewDeletion(TObject *Sender, TListItem *Item)
{
   T* pObject = (T*)(Item->Data);
   if (pObject)
   {
      delete pObject;
      Item->Data = NULL;
   }
}
//---------------------------------------------------------------------------
// This event handles automatic sorting.
template <class T>
void __fastcall ListViewManager<T>::OnListViewColumnClick( TObject *Sender,
                                                       TListColumn *Column)
{
   int iColumn = 0;
   for (int i = 0; i < lvList->Columns->Count; i++)
      if (lvList->Columns->Items[i] == Column)
      {
         iColumn = i;
         break;
      }
   lvList->CustomSort(NULL, iColumn);
   if (iCurrentSort == iColumn)
      iCurrentSort = -1;
   else
      iCurrentSort = iColumn;
   if (OldOnColumnClick)
      OldOnColumnClick(Sender, Column);
}
//---------------------------------------------------------------------------
// This event sorts columns by doing a string comparison.
template <class T>
void __fastcall ListViewManager<T>::OnListViewCompare( TObject *Sender,
                                                TListItem *Item1,
                                                TListItem *Item2,
                                                int Data,
                                                int &Compare)
{
   String sValue1;
   String sValue2;
   if (Data == 0)
   {
      sValue1 = Item1->Caption;
      sValue2 = Item2->Caption;
   }
   else
   {
      sValue1 = Item1->SubItems->Strings[Data - 1];
      sValue2 = Item2->SubItems->Strings[Data - 1];
   }
   Compare = sValue1.AnsiCompareIC(sValue2);
   if (iCurrentSort == Data)
   {
      Compare = -Compare;
   }
}
//---------------------------------------------------------------------------
#endif

Second:
Create a class like this:
The class will have as many attributes as elements you want to sort.
This class can be at the .cpp file

class LastCyborg
{
protected:
   AnsiString sName;
   AnsiString sDate;
   AnsiString sTime;
///   ... etc.

public:
   LastCyborg(AnsiString Name, AnsiString Date, AnsiString Time /*...etc. */);
   AnsiString GetColumnString(int iColumn);
};

LastCyborg::LastCyborg(AnsiString Name, AnsiString Date, AnsiString Time /*...etc. */);
{
   sName = Name;
   sDate = Date;
   sTime = Time;
}
//---------------------------------------------------------------------------
AnsiString LastCyborg::GetColumnString(int iColumn)
{
   switch (iColumn)
   {
      case 0: return sName;
      case 1: return sDate;
      case 2: return sTime;
      //...etc.
   }
   return "";
}
//---------------------------------------------------------------------------

Finally
Using the class
// the next code can be in any event handler

   ListView1->Clear();
   ListViewManager<LastCyborg> *List = new ListViewManager<LastCyborg>(ListView1);
List->AddObject(new LastCyborg(YourNameValue,YourDateValue,
YourTimeValue));
   delete List;

Doing that, is suppossed that if you press any of the Fixed buttons of the ListView the data will be sorted.

That code is just a piece of a program that I downloaded. so that is not mine I just took that part and I modified, but I hope it help you



--- LastCyborg ---