Changing the row color dinamically by using a delegate function that depends on row number

S

SammyBar

This is a helper class that enables to display the row back and fore color
on a per row basis. The color is specified by a delegate function that takes
the row number as a parameter. This is a small modification of the class
DataGridEvenOddRows published by Alex Feinman here:

http://www.opennetcf.org/Forums/topic.asp?TOPIC_ID=350



using System;

using System.Drawing;

using System.Collections;

using System.Windows.Forms;

using System.Data;

using System.Reflection;

namespace Conteo

{

/// <summary>

/// Summary description for DataGridEvenOddHandler.

/// </summary>

class DataGridRowColorHandler : IDisposable

{

public delegate Colors GetRowColor(int iRow);

private GetRowColor fGetRowColor;

private DataGrid m_grid;

private object m_r;

//private Color[] arrClr = new Color[] { Color.Cyan, Color.LightYellow };

//private Color[] arrClrText = new Color[] { Color.Black, Color.Black };

private SolidBrush brCell, brCellFore;

private FieldInfo m_fiRowVisibleFirst, m_fiRowVisibleLast,
m_fiColVisibleFirst, m_fiColVisibleLast;

private FieldInfo m_fiRowDrawFirst, m_fiRowDrawLast, m_fiColDrawFirst,
m_fiColDrawLast;

private FieldInfo m_fiRows;

private MethodInfo m_miDrawCells;

private DataGridCell currentCell;

private int iRowVisibleFirst, iRowVisibleLast, iColVisibleFirst,
iColVisibleLast;

private int RowIndex = -1;

public DataGridRowColorHandler(DataGrid grid, GetRowColor
aGetRowColorDelegateFunction)

{

m_grid = grid;

fGetRowColor = aGetRowColorDelegateFunction;

HookGrid();

}

private void HookGrid()

{

m_r = typeof(DataGrid).GetField("m_renderer", BindingFlags.NonPublic |
BindingFlags.GetField | BindingFlags.Instance).GetValue(m_grid);

m_fiRowDrawFirst = m_r.GetType().GetField("m_irowDrawFirst",
BindingFlags.NonPublic | BindingFlags.GetField | BindingFlags.Instance);

m_fiRowDrawLast = m_r.GetType().GetField("m_irowDrawLast",
BindingFlags.NonPublic | BindingFlags.GetField | BindingFlags.Instance);

m_fiColDrawFirst = m_r.GetType().GetField("m_icolDrawFirst",
BindingFlags.NonPublic | BindingFlags.GetField | BindingFlags.Instance);

m_fiColDrawLast = m_r.GetType().GetField("m_icolDrawLast",
BindingFlags.NonPublic | BindingFlags.GetField | BindingFlags.Instance);

m_fiRowVisibleFirst = typeof(DataGrid).GetField("m_irowVisibleFirst",
BindingFlags.NonPublic | BindingFlags.GetField | BindingFlags.Instance);

m_fiRowVisibleLast = typeof(DataGrid).GetField("m_irowVisibleLast",
BindingFlags.NonPublic | BindingFlags.GetField | BindingFlags.Instance);

m_fiColVisibleFirst = typeof(DataGrid).GetField("m_icolVisibleFirst",
BindingFlags.NonPublic | BindingFlags.GetField | BindingFlags.Instance);

m_fiColVisibleLast = typeof(DataGrid).GetField("m_icolVisibleLast",
BindingFlags.NonPublic | BindingFlags.GetField | BindingFlags.Instance);

m_fiRows = typeof(DataGrid).GetField("m_rlrow", BindingFlags.NonPublic |
BindingFlags.GetField | BindingFlags.Instance);

m_miDrawCells = m_r.GetType().GetMethod("_DrawCells", BindingFlags.NonPublic
| BindingFlags.Instance);

brCell = (SolidBrush)m_r.GetType().GetField("m_brushCellBack",
BindingFlags.NonPublic | BindingFlags.GetField |
BindingFlags.Instance).GetValue(m_r);

brCellFore = (SolidBrush)m_r.GetType().GetField("m_brushCellFore",
BindingFlags.NonPublic | BindingFlags.GetField |
BindingFlags.Instance).GetValue(m_r);

//currentCell = new DataGridCell(-1, -1);

VScrollBar vsb = (VScrollBar)typeof(DataGrid).GetField("m_sbVert",
BindingFlags.NonPublic | BindingFlags.GetField |
BindingFlags.Instance).GetValue(m_grid);

HScrollBar hsb = (HScrollBar)typeof(DataGrid).GetField("m_sbHorz",
BindingFlags.NonPublic | BindingFlags.GetField |
BindingFlags.Instance).GetValue(m_grid);

vsb.ValueChanged += new EventHandler(vsb_ValueChanged);

hsb.ValueChanged += new EventHandler(hsb_ValueChanged);

m_grid.Paint += new PaintEventHandler(grid_Paint);

m_grid.CurrentCellChanged += new EventHandler(grid_CurrentCellChanged);

currentCell = m_grid.CurrentCell;

iRowVisibleFirst = (int)m_fiRowVisibleFirst.GetValue(m_grid);

iRowVisibleLast = (int)m_fiRowVisibleLast.GetValue(m_grid);

iColVisibleFirst = (int)m_fiColVisibleFirst.GetValue(m_grid);

iColVisibleLast = (int)m_fiColVisibleLast.GetValue(m_grid);

}

private void UnhookGrid()

{

if (m_grid == null)

return;

VScrollBar vsb = (VScrollBar)typeof(DataGrid).GetField("m_sbVert",
BindingFlags.NonPublic | BindingFlags.GetField |
BindingFlags.Instance).GetValue(m_grid);

HScrollBar hsb = (HScrollBar)typeof(DataGrid).GetField("m_sbHorz",
BindingFlags.NonPublic | BindingFlags.GetField |
BindingFlags.Instance).GetValue(m_grid);

vsb.ValueChanged -= new EventHandler(vsb_ValueChanged);

hsb.ValueChanged -= new EventHandler(hsb_ValueChanged);

m_grid.Paint -= new PaintEventHandler(grid_Paint);

m_grid.CurrentCellChanged -= new EventHandler(grid_CurrentCellChanged);

}

//public Color OddRowColor

//{

// get { return arrClr[1]; }

// set { arrClr[1] = value; /*grid_Paint(null, null);*/ }

//}

//public Color EvenRowColor

//{

// get { return arrClr[0]; }

// set { arrClr[0] = value; /*grid_Paint(null, null); */}

//}

//public Color OddRowTextColor

//{

// get { return arrClrText[1]; }

// set { arrClrText[1] = value; /*grid_Paint(null, null);*/ }

//}

//public Color EvenRowTextColor

//{

// get { return arrClrText[0]; }

// set { arrClrText[0] = value; /*grid_Paint(null, null); */}

//}

private void ForceRepaintGridRow(Graphics g, int row)

{

Colors colors = fGetRowColor(row);

//brCell.Color = arrClr[row % 2];

//brCellFore.Color = arrClrText[row % 2];

brCell.Color = colors.BackColor;

brCellFore.Color = colors.ForeColor;

m_fiRowDrawFirst.SetValue(m_r, row);

m_fiRowDrawLast.SetValue(m_r, row);

m_miDrawCells.Invoke(m_r, new object[] { g });

}

private void ForceRepaintGridRows(Graphics g, int rowStart, int rowEnd)

{

for (int i = rowStart; i <= rowEnd; i++)

{

Colors colors = fGetRowColor(i);

//brCell.Color = arrClr[i % 2];

//brCellFore.Color = arrClrText[i % 2];

brCell.Color = colors.BackColor;

brCellFore.Color = colors.ForeColor;

m_fiRowDrawFirst.SetValue(m_r, i);

m_fiRowDrawLast.SetValue(m_r, i);

m_miDrawCells.Invoke(m_r, new object[] { g });

}

}

private void ForceRepaintGridRows(Graphics g, int[] range)

{

foreach (int i in range)

{

Colors colors = fGetRowColor(i);

//brCell.Color = arrClr[i % 2];

//brCellFore.Color = arrClrText[i % 2];

brCell.Color = colors.BackColor;

brCellFore.Color = colors.ForeColor;

m_fiRowDrawFirst.SetValue(m_r, i);

m_fiRowDrawLast.SetValue(m_r, i);

m_miDrawCells.Invoke(m_r, new object[] { g });

}

}

private void vsb_ValueChanged(object sender, EventArgs e)

{

int iRowFirst = (int)m_fiRowVisibleFirst.GetValue(m_grid);

int iRowLast = (int)m_fiRowVisibleLast.GetValue(m_grid);

Graphics g = m_grid.CreateGraphics();

if (iRowVisibleFirst > iRowFirst) //Scroll Up

{

ForceRepaintGridRows(g, iRowFirst, iRowVisibleFirst);

}

else

{

ForceRepaintGridRows(g, iRowVisibleLast, iRowLast);

}

iRowVisibleFirst = iRowFirst;

iRowVisibleLast = iRowLast;

//grid_Paint(null, null);

}

private void hsb_ValueChanged(object sender, EventArgs e)

{

grid_Paint(null, null);

}

#region IDisposable Members

public void Dispose()

{

UnhookGrid();

}

#endregion

private void grid_Paint(object sender, PaintEventArgs e)

{

int rowFirst, rowLast;

rowFirst = (int)m_fiRowVisibleFirst.GetValue(m_grid);

rowLast = (int)m_fiRowVisibleLast.GetValue(m_grid);

rowFirst = Math.Max(rowFirst, 0);

rowLast = Math.Max(rowLast, 0);

Color cl = brCell.Color;

Color clText = brCellFore.Color;

Graphics g;

g = m_grid.CreateGraphics();

ForceRepaintGridRows(g, rowFirst, rowLast);

brCell.Color = cl;

brCellFore.Color = clText;

}

private void grid_CurrentCellChanged(object sender, EventArgs e)

{

Color cl = brCell.Color;

Color clText = brCellFore.Color;

Graphics g = m_grid.CreateGraphics();

int nFirstVisibleRow = (int)m_fiRowVisibleFirst.GetValue(m_grid);

ArrayList Rows = (ArrayList)m_fiRows.GetValue(m_grid);

object Row;

FieldInfo fiSelected = Rows[0].GetType().GetField("m_fSelected",
BindingFlags.NonPublic | BindingFlags.GetField | BindingFlags.Instance);

if (RowIndex > -1)

{

Row = Rows[RowIndex];

if ((bool)fiSelected.GetValue(Row))

m_grid.Invalidate(_GetRowBounds(RowIndex));

else

ForceRepaintGridRow(g, RowIndex);

}

currentCell = m_grid.CurrentCell;

RowIndex = m_grid.CurrentRowIndex;

if (RowIndex > -1)

{

Row = Rows[RowIndex];

if ((bool)fiSelected.GetValue(Row))

m_grid.Invalidate(_GetRowBounds(RowIndex));

else

ForceRepaintGridRow(g, RowIndex);

}

brCell.Color = cl;

brCellFore.Color = clText;

}

private Rectangle _GetRowBounds(int iRow)

{

int colFirst = (int)m_fiColVisibleFirst.GetValue(m_grid);

int colLast = (int)m_fiColVisibleLast.GetValue(m_grid);

Rectangle r = m_grid.GetCellBounds(iRow, colFirst);

for (int i = colFirst; i <= colLast; i++)

{

Rectangle rNew = m_grid.GetCellBounds(iRow, i);

r.X = Math.Min(r.X, rNew.X);

r.Width = Math.Max(r.Right, rNew.Right) - Math.Min(r.X, rNew.X);

}

return r;

}

}

}
 

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