(C++ VCL) TStringGrid

Visual Component resembling a table for display and input.

Forward declaration:

namespace Grids { class TStringGrid; };

In the implementation (.cpp) file, #include grids.hpp:

include <grids.hpp>

How to: add a TComboBox to a TStringGrid

Modified from the Borland community, from the Delphi code at http://community.borland.com/article/0,1410,17434,00.html

__fastcall TForm1::TForm1(TComponent* Owner)
  : TForm(Owner)
{
  //The combobox height is not settable, so we will 
  //instead size the grid to fit the combobox! 
  StringGrid1->DefaultRowHeight = ComboBox1->Height; 
  //Hide the combobox 
  ComboBox1->Visible = False; 
}
//---------------------------------------------------------------------------
void __fastcall TForm1::ComboBox1Change(TObject *) 
{ 
  //Get the ComboBox selection and place in the grid 
  //Note that the lines below are NOT bulletproof. 
  //With some heavy clicking you can change Row and Col 
  //so it writes to another cell 
  if (StringGrid1->Col !=3 ) 
  { 
    StringGrid1->Col = 3; 
    ShowMessage("Prevention!"); 
  } 
  if (StringGrid1->Row <1 ) 
  { 
    StringGrid1->Row = 1; 
    ShowMessage("Prevention!"); 
  }
  StringGrid1->Cells[StringGrid1->Col][StringGrid1->Row] =
    ComboBox1->Items->operator [](ComboBox1->ItemIndex); 
  ComboBox1->Visible = False; 
  StringGrid1->SetFocus(); 
}
//---------------------------------------------------------------------------
void __fastcall TForm1::StringGrid1SelectCell(
  TObject *, int ACol, int ARow, bool &CanSelect) 
{ 
  if (ACol == 3 && ARow > 0) 
  { //Size and position the combo box to fit the cell 
    TRect R = StringGrid1->CellRect(ACol, ARow); 
    R.Left   += StringGrid1->Left; 
    R.Right  += StringGrid1->Left; 
    R.Top    += StringGrid1->Top; 
    R.Bottom += StringGrid1->Top; 
    ComboBox1->Left = R.Left + 1; 
    ComboBox1->Top = R.Top + 1; 
    ComboBox1->Width = (R.Right + 1) - R.Left; 
    ComboBox1->Height = (R.Bottom + 1) - R.Top; 
    //Show the combobox 
    ComboBox1->Visible = true; 
    ComboBox1->SetFocus(); 
  } 
  CanSelect = true; 
}

How to: let a StringGrid size itself to the text it contains?

void autoSize(TStringGrid * stringGrid)
{
  const int nCols = stringGrid->ColCount;
  const int nRows = stringGrid->RowCount;
  int sumWidth = 0;
  for (int x=0; x!=nCols; ++x)
  {
    int maxWidth = -1;
    for (int y=0; y!=nRows; ++y)
    {
      const int width = stringGrid->Cells[x][y].Length() * 8 + 5;
      if (width > maxWidth)
      {
        maxWidth = width;
      }
    }
    stringGrid->ColWidths[x] = maxWidth;
    sumWidth +=maxWidth;
  }
  stringGrid->Width = sumWidth + 7;
}

How to: Sort a StringGrid ?

Here's an implementation assuming the StringGrid is filled with integers.

void swapRows(TStringGrid * const stringGrid,const int& row1,const int& row2)
{
  const int nCols = stringGrid->ColCount;
  for (int j=0; j<nCols; ++j)
  {
    const String t = stringGrid->Cells[j][row1];
    stringGrid->Cells[j][row1] = stringGrid->Cells[j][row2];
    stringGrid->Cells[j][row2] = t;
  }
}
void sortStringGrid(TStringGrid * const grid, const int& col)
{
  const int fixedRows = grid->FixedRows;
  const int nRows     = grid->RowCount;
  //Sort the StringGrid
  for (int i=fixedRows; i!=nRows-1; ++i)
  {
    for (int y=fixedRows; y!=nRows-1; ++y)
    {
      const String upper = grid->Cells[col][y  ];
      const String lower = grid->Cells[col][y+1];
      if (upper.ToDouble() < lower.ToDouble()) { swapRows(grid,y,y+1); }
    }
  }
}

Convert a TStringGrid to a matrix

The matrix is implemented by a two dimensional std::vector.

include <cassert>


std::vector<std::vector<double> > Convert(const TStringGrid * const stringGridOriginal)
{
  //Need to cast away const as the VCL is not const-correct. Grumble, grumble...
  TStringGrid * const stringGrid = const_cast<TStringGrid*>(stringGridOriginal);
  assert(stringGrid!=0);
  assert(stringGrid->FixedCols == 0);
  assert(stringGrid->FixedRows == 0);
  const int maxx = stringGrid->ColCount;
  const int maxy = stringGrid->RowCount;
  std::vector<std::vector<double> > matrix(maxx,std::vector<double>(maxy,0.0));
  for (int y=0; y!=maxy; ++y)
  {
    for (int x=0; x!=maxx; ++x)
    {
      const String myString = stringGrid->Cells[x][y];
      double rDouble = 0.0;
      const bool success = TryStrToFloat(myString, rDouble);
      assert(success == true);
      matrix[x][y] = rDouble;
    }
  }
  return matrix;
}

Code links

'TStringGrid' links

C++ CLX
C++ Builder
Pascal VCL
Pascal CLX

last edited (December 20, 2006) by bilderbikkel, Number of views: 3631, Current Rev: 7 (Diff)

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