编程更改公式字段示例代码

using CrystalDecisions.CrystalReports.Engine;

namespace GMedicine
{
/// <summary>
/// FormGMedicine 的摘要说明。
/// </summary>
public class FormGMedicine : System.Windows.Forms.Form
{
private const string CR_PATH = @"../../RPTGMedicine.rpt";
private const string FORMULA_FIELD_NAME = @"Group";
private string[] FORMULA_FIELD_TEXT = {"{客户.国家和地区}", "{客户.城市}",
"{客户.联系人职位}", "{客户.地区}"};

private CrystalDecisions.Windows.Forms.CrystalReportViewer crvGMedicine;
private GMedicine.RPTGMedicine rptGMedicine;
private System.Windows.Forms.ComboBox cbxSelectGroup;

private void FormGMedicine_Load(object sender, System.EventArgs e)
{
LoadFormulaList();

crvGMedicine.ReportSource = rptGMedicine;

crvGMedicine.RefreshReport();
}

private void cbxSelectGroup_SelectedIndexChanged(object sender, System.EventArgs e)
{
FormulaFieldDefinition formulaField;

formulaField = GetFormulaField(rptGMedicine, FORMULA_FIELD_NAME);

formulaField.Text = cbxSelectGroup.SelectedItem.ToString();

crvGMedicine.RefreshReport();
}

private FormulaFieldDefinition GetFormulaField(ReportDocument Report, string formulaFieldName)
{
FormulaFieldDefinition formulaField;

// 按名称获取 FormulaFieldDefinition，
//并返回此对象。
formulaField = Report.DataDefinition.FormulaFields[formulaFieldName];
if (formulaField != null) return formulaField;
else return null;
}

private void LoadFormulaList()
{
foreach (string formula in FORMULA_FIELD_TEXT)
{
cbxSelectGroup.Items.Add(formula);
}
}
}
}