In C# .NET 2 winforms application I need to set table header forecolor and backcolor properties:

using System.Windows.Forms;
DataGridTableStyle tableStyle = new DataGridTableStyle();
Desktop td = new Desktop();
td.GetColors(tableStyle.HeaderForeColor,
    tableStyle.HeaderBackColor);

However colors are not changed since it seems that parameters are passed by value.
Which is the best practice for change colors ?
I'll prefer to execute only one query in sql server and not to add additional properties, classes and structures to code.

Desktop class GetColors method contains:

public void GetColors(System.Drawing.Color foreColor,
			System.Drawing.Color backColor) {

IDataReader tableReader = ExecReader(
   "SELECT hforecol,hbackcol FROM desktop");
if (tableReader.Read()) {
	foreColor = GetColor(tableReader.GetDecimal(0));
	backColor = GetColor(tableReader.GetDecimal(1));
	}
tableReader.Close();
}