XtraReport1.cs

using CustomReportParameterType.Services;
using DevExpress.XtraReports.Parameters;
using System.Collections.Generic;

public partial class XtraReport1 : DevExpress.XtraReports.UI.XtraReport
{
    public XtraReport1()
    {
        InitializeComponent();

        var staticListLookUpSettings1 = new StaticListLookUpSettings();
        var staticListLookUpSettings2 = new StaticListLookUpSettings();
        // 
        // customMailParameterLookup
        // 
        customMailParameterLookup.Description = "Custom Email Parameter";
        customMailParameterLookup.Name = "customMailParameterLookup";
        customMailParameterLookup.Type = typeof(CustomParameterType);
        var parameterLookUpValue1 = new CustomParameterType { Value = "MyFirtsMail@example.com" };
        var parameterLookUpValue2 = new CustomParameterType { Value = "MySecondMail@example.com" };
        staticListLookUpSettings1.LookUpValues.AddRange(new List<LookUpValue> {
            new LookUpValue(parameterLookUpValue1, "First Mail Value"),
            new LookUpValue(parameterLookUpValue2, "Second Mail Value")
        });
        customMailParameterLookup.ValueSourceSettings = staticListLookUpSettings1;
        // 
        // customMailParameterText
        // 
        customMailParameterText.Description = "Additional Custom Email Parameter";
        customMailParameterText.Name = "customMailParameterText";
        customMailParameterText.Type = typeof(CustomParameterType);
        customMailParameterText.Value = new CustomParameterType { Value = "SampleMail@example.com" };
        // 
        // customMailParameterMultivalue
        // 
        customMailParameterMultivalue.Description = "Multi-value Email Parameter";
        customMailParameterMultivalue.MultiValue = true;
        customMailParameterMultivalue.Name = "customMailParameterMultivalue";
        customMailParameterMultivalue.Type = typeof(CustomParameterType);
        customMailParameterMultivalue.Value = new List<CustomParameterType> {
            new CustomParameterType { Value = "FirstSampleMail@example.com" },
            new CustomParameterType { Value = "SecondSampleMail@example.com" }
        };
        // 
        // customMailParameterMultivalueLookup
        // 
        customMailParameterMultivalueLookup.Description = "Predefined multi-value Email parameter";
        customMailParameterMultivalueLookup.MultiValue = true;
        customMailParameterMultivalueLookup.Name = "customMailParameterMultivalueLookup";
        customMailParameterMultivalueLookup.Type = typeof(CustomParameterType);
        var parameterLookUpValue3 = new CustomParameterType { Value = "MyThirdMail@example.com" };
        var parameterLookUpValue4 = new CustomParameterType { Value = "MyFourthMail@example.com" };
        staticListLookUpSettings2.LookUpValues.AddRange(new List<LookUpValue> {
            new LookUpValue(parameterLookUpValue3, "Third Mail Value"),
            new LookUpValue(parameterLookUpValue4, "Fourth Mail Value")
        });
        customMailParameterMultivalueLookup.ValueSourceSettings = staticListLookUpSettings2;
    }
}