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Problem
I have a large grid with many rows and I would like to display rows with optimal height. How can I delay resizing the rows so that the row heights are only calculated before the row gets displayed?
Cause
Action
Please add the following declarations to your view:
| virtual int GetRowHeight(ROWCOL nRow); virtual long OnCalcRowHeightOnDemand(ROWCOL nRow); |
and the following code in the implementation .cpp file:
| class CMyParam : public CGXGridParam { |
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| friend class C1stGridView; | ||||
| };
int C1stGridView::GetRowHeight(ROWCOL nRow) |
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| CMyParam* pParam = (CMyParam*) GetParam();
// if height of this row is already computed if (!IsRowHidden(nRow) && !pParam->m_RowHeights.Lookup(nRow, nHeight)) |
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| pParam->m_RowHeights.SetAt(nRow, Height_DPtoLP(GetDefaultRowHeight()));
nHeight = OnCalcRowHeightOnDemand(nRow); pParam->m_RowHeights.SetAt(nRow, Height_DPtoLP(nHeight)); |
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| }
return CGXGridCore::GetRowHeight(nRow); |
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| }
long C1stGridView::OnCalcRowHeightOnDemand(ROWCOL nRow) |
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| // Compute height of this row // (code copied from ResizeRowHeightsToFit) CGXStyle* pStyleStandard = &StandardStyle(); CClientDC dc(m_pGridWnd); OnGridPrepareDC(&dc); // Select default font into for (ROWCOL nCol = GetHeaderCols()+1; nCol <= nColCount; nCol++) |
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| if (GetColWidth(nCol) > 0) { |
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| CGXStyle* pStyle = CreateStyle(); ComposeStyleRowCol(nRow, nCol, pStyle); CGXControl* pControl = GetRegisteredControl(pStyle->GetControl()); CSize size = pControl->CalcSize(&dc, nRow, nCol, *pStyle, pStyleStandard, TRUE); nHeight = max(nHeight, size.cy); // Style object recycling |
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| } | ||||
| }
if (pOldFont) |
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| dc.SelectObject(pOldFont); | ||||
| return nHeight; | ||||
| } | ||||
If necessary, you can force that all row heights will be recalculated by emptying pParam->m_RowHeights.
