Form1.cs

using System;
using DevExpress.XtraReports.Parameters;
using DevExpress.XtraReports.UI;

namespace ReportParameterExample {
    public partial class Form1 : DevExpress.XtraEditors.XtraForm {
        public Form1() {
            InitializeComponent();
        }

        private void simpleButton1_Click(object sender, EventArgs e) {
            // Create a report instance.
            XtraReport1 report = new XtraReport1();

            // Create a parameter and specify its name.
            Parameter param1 = new Parameter();
            param1.Name = "CatID";

            // Specify other parameter properties.
            param1.Type = typeof(System.Int32);
            param1.Value = 1;
            param1.Description = "Category: ";
            param1.Visible = true;

            // Add the parameter to the report.
            report.Parameters.Add(param1);

            // Specify the report's filter string.
            report.FilterString = "[CategoryID] = [Parameters.CatID]";

            // Force the report creation without previously 
            // requesting the parameter value from end-users.
            report.RequestParameters = false;

            // Show the parameter's value on a Report Header band.
            XRLabel label = new XRLabel();
            label.ExpressionBindings.Add(new ExpressionBinding("BeforePrint", "Text", "Category: [CategoryName]"));
            ReportHeaderBand reportHeader = new ReportHeaderBand();
            reportHeader.Controls.Add(label);
            report.Bands.Add(reportHeader);

            // Assign the report to a ReportPrintTool,
            // to hide the Parameters panel,
            // and show the report's print preview.
            ReportPrintTool pt = new ReportPrintTool(report);
            pt.AutoShowParametersPanel = true;
            pt.ShowPreviewDialog();
        }
    }
}