void listBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
            PivotComputationInfo info = listBox1.SelectedItem as PivotComputationInfo;

            if (info != null)
            {
                this.textBoxDescription.Text = string.Format(pivotGrid.DefaultDescriptionFormat, info.CalculationName, ComputationInfo.FieldName);
            }
        }
        private void MoveComputationInfoFromForm()
        {
            this.ComputationInfo.Description = textBoxDescription.Text;
            this.ComputationInfo.Format      = textBoxFormat.Text;
            PivotComputationInfo info = listBox1.SelectedItem as PivotComputationInfo;

            if (info != null)
            {
                this.ComputationInfo.Summary = info.Summary;
                this.ComputationInfo.Pd      = info.Pd;
                //   this.ComputationInfo.FieldName = info.FieldName;  cnnot change the FieldName
                this.ComputationInfo.CalculationName = info.CalculationName;
            }
        }