private void ShowFormulaDialog()
        {
            UltraGridColumn column = this.FirstGridBand.Columns["UsageFormula"];
            if (column == null)
            {
                return;
            }

            this.ShowFormulaBuilderDialog(column as IFormulaProvider);

        }


        private void ShowFormulaBuilderDialog(IFormulaProvider formulaProvider)
        {
            // Declare a new FormulaBuilderDialog			
            FormulaBuilderDialog formulaBuilderDialog = null;

            try
            {
                formulaBuilderDialog = new FormulaBuilderDialog(formulaProvider);
                formulaBuilderDialog.OperandInitializing += new OperandInitializingEventHandler(this.formulaBuilder_OperandInitializing);
                formulaBuilderDialog.FunctionInitializing += new FunctionInitializingEventHandler(this.formulaBuilder_FunctionInitializing);

                // Show the dialog
                DialogResult dResult = formulaBuilderDialog.ShowDialog(this);

                // If the user cancelled, do nothing
                if (dResult == DialogResult.Cancel)
                    return;

                // Apply the formula
                formulaProvider.Formula = formulaBuilderDialog.Formula;
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
            finally
            {
                if (formulaBuilderDialog != null)
                {
                    // Whatever happens, make sure we disconnect from 
                    // the events
                    formulaBuilderDialog.OperandInitializing -= new OperandInitializingEventHandler(this.formulaBuilder_OperandInitializing);
                    formulaBuilderDialog.FunctionInitializing -= new FunctionInitializingEventHandler(this.formulaBuilder_FunctionInitializing);
                    formulaBuilderDialog.Dispose();
                    formulaBuilderDialog = null;
                }
            }
        }