The method, string.Format, returns a string. The first argument for string.Format is a string that defines what the returned string should be. In this first argument, {x} where x in an integer, defines tokens that represent the values from the other items in the string.Format arguement list. So, {0} represents the value of the second argument in the string.Format argument list, {1} is the 3rd argument, and so on. GridRangeInfo.GetAlphaLabel is a function that accepts an integer and returns the corresponding letter of the alphabet that normally serves as the column header text for the particular column. So, GridRangeInfo.GetAlphaLabel(1) is "A", GridRangeInfo.GetAlphaLabel(2) is "B", and so on. The other method does the same except it returns a number that normally serves an teh row header text, "1", "2" etc.
One way to prevent the formula from displaying is to handle the CurrentCellStartEditing event and cancel it if it is a formula cell you don''t want to edit.
private void gridControl1_CurrentCellStartEditing(object sender, CancelEventArgs e)
{
GridCurrentCell cc = this.gridControl1.CurrentCell;
if(this.gridControl1[cc.RowIndex, cc.ColIndex].CellType == "FormulaCell")
e.Cancel = true;
}