Attempting to Change Color of Datagrid Cells [C#]

Given the following code [ds = dataset, dt = datatable, dg = datagrid];

ds.Tables.Add(dt);
DataGridTableStyle tableStyle = new DataGridTableStyle();
tableStyle.MappingName = "0";
int numCols = ds.Tables[0].Columns.Count;
DataGridColoredTextBoxColumn aColumnTextColumn;
for(int i = 0; i < numCols; ++i)
{
aColumnTextColumn = new DataGridColoredTextBoxColumn();
aColumnTextColumn.HeaderText = ds.Tables[0].Columns[i].ColumnName;

aColumnTextColumn.MappingName = ds.Tables[0].Columns[i].ColumnName;
tableStyle.GridColumnStyles.Add(aColumnTextColumn);
}

DG.TableStyles.Clear();
DG.TableStyles.Add(tableStyle);
DG.DataSource = ds.Tables[0];
}

public class DataGridColoredTextBoxColumn : DataGridTextBoxColumn
{
protected override void Paint(System.Drawing.Graphics g, System.Drawing.Rectangle bounds, System.Windows.Forms.CurrencyManager source, int rowNum, System.Drawing.Brush backBrush, System.Drawing.Brush foreBrush, bool alignToRight)
{
try
{
object o = this.GetColumnValueAtRow(source, rowNum);
if( o!= null)
{
backBrush = new SolidBrush(Color.Aquamarine);
foreBrush = new SolidBrush(Color.Blue);

catch(Exception ex){ /* empty catch */ }
finally
{
base.Paint(g, bounds, source, rowNum, backBrush, foreBrush, alignToRight);
}
}

I saw this code posted in many forums and help pages so assumed it would be the best to use, all I want is to change the color of my Datagrid Cell if the value does not match a default value provided.

This code is supposed to change all my Cells to the backBrush (aquamarine) and foreBrush (blue) however when I run the program nothing has changed [generates no errors either but Datagrid cells are all still black on white].

Any clues what I am doing wrong?

Note that my dataset [ds] is created dynamically by adding Rows/Columns, I am unsure about the “MappingName” and “ColumnName” properties [seeing as my ds was generated dynamically and not from a Database like SQL, all I did was .add Columns and .add Rows in For loops]